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Review continued in post #2 because of the 100,000 character limit per post.
In the final ranking, the 8 amps in 1st -5th place are close enough to be a tie, and my ranking is based on personal preference and features, not only sound.
3/14/08 - Initial Review Four USB DAC Amps: Tonight I compared SEVERAL USB DAC amps that I own. SEE UPDATES BELOW FOR ADDITIONAL AMPS - including the 2MOVE and HR Micro Stack, the D2 Boa, the Vivid Technology V1, iBasso D3 Python, Nuforce Icon Mobile, Practical Devices XM5, iBasso D10 and D4 in Post #2.
(1) RSA Predator #24 with 1100+ hours, reviewed by Skylab last month
(2) Pico #11 formerly owned by Asr and broken in
(3) iBasso D2 with 183 hours
(4) Headstage Lyrix with 400+ hours
PHONES: I reviewed them using my ALO modded Vampire wire HFI-780's which have 450 hours on them - these have excellent frequency response and transparency, and are ruthless in exposing a bad source or amp, and fantastic at exploiting a good source or amp.
SOURCE: Listening was via USB on a Macbook with Apple lossless files as the source. At any one time, two of the four amps were connected via USB, and I would switch ports via the sound control panel, then quickly swap the headphone plug out. All amps were on low gain - and I tried to match volumes by ear - the Lyrix and D2 volume knobs were at 1:30 o'clock, the Pico was at 1 o'clock, and the Predator was at 3:30 (but it is the only one with three gain levels).
MUSIC: Apple lossless files - Tsuyoshi Yamamoto "Autumn in Seattle", FIM "This is K2 HD CD" and "Jazz at the Pawnshop", Diana Krall "Girl in the Other Room" Dual-Disc.
FINDINGS: They are all very good, but have differences. You would not be dissatisfied with any of them, but you can tell which are the $500 amps and which are the $200 amps. If the money is there, I would give it up for the more expensive ones; not because of the cost, but because of the open windows into the music they provide.
FIRST: The Predator is still my current favorite for sounding like a full size amp (so far), but I have more sources and phones to try all the amps with. The bass is deep without being boomy, and the mids and highs are warm and smooth, with good transparency. It does have a just a little bit less treble extension than the Pico, which is fine with the ALO modded HFI780's and most headphones. I have tried high gain before, and it drives HD600 with no strain at all.
The Predator strikes me as being different, in the same way that a wood Grado has a different timbre than a plastic or metal Grado - with the Predator being wood with warm natural timbre and the Pico being the "not-wood" or more neutral one.
SECOND: As a very close second is the Pico S/N #11 which was the one used in Asr's loaner tests (many hours on it) and it just arrived today. It was nice, but with maybe/possibly a little tipped up extreme ends of the bass and treble, adding a slight brightness but not sibilance. Otherwise it is pretty neutral and powerful, but slightly colder than the Predator. Both are equally detailed, however the PICO soundstage is a tad larger or slightly more open sounding.
I would bet that some of my headphones might appreciate the neutrality a little more, and I will explore that. However, I can see why many people are using these as a volume controlled DAC, because it doesn't seem to have much of a flavor of it's own. I will try it as a DAC to my tube amplifier, and report back later.
THIRD: [SEE UPDATE BELOW, AFTER BURN-IN AND NEW OPAMPS D2 VIPER MOVED TO SECOND] In 3rd is the iBasso D2. It has a very similar sound signature and frequency response as the Pico - but maybe tiny bit boomy in the bass, a tiny bit less volume in the mids and a little bit brighter in the treble (more U-shaped). It was not quite as smooth in the treble or as transparent as the PICO (D2 has 183 hours on it).
The bass has gone up and down over the past 48 hours, and for a while it was too much, but it is leveling out now but still slightly more than needed. I expect it to continue to refine itself with more hours under the belt.
FOURTH: Then there is the Headstage Lyrix Total Pro USB. Fourth place doesn't mean last place, since it is still a very good amp. It sounds very similar to the D2 in frequency response, but with a little less transparency than the D2. Switching between the Pico on one USB port and Lyrix on the other USB, then the decrease in transparency even more apparent. It is still a very detailed and clean amp, but with less air around the instruments vs the other amps when driven by it's limited PCM2704 DAC. The bass was not boomy unless the bass boost was switched on, but it was slightly less than the D2 when off. In no way was the bass inadequate, rather the D2 is just a smidge much (is that a word?).
This amp has loads of features, like 9v re-chargable or Alkaline compatable, with charge circuit off-switch, bass boost, crossfeed. BUT, it is also twice as big as the other three (sorry no pic, it got left out in my wife's car when she took my daughter to girl scouts). It has been relegated to being the desktop amp for the iMac in our kitchen because it is still too good to sell.
WHAT'S MISSING: You may ask, where is the iBasso D1? Well... Blutarsky had sold off all his portable amps, and I loaned him my D1 two weeks ago to try with his ALO vampire wire 780's. I had recently rolled the opamps to AD743/LMH6643/LTC6241 which synergized very well with them. Somehow, last weekend I left his house owning all of his headphones except his Darths and my HP-1000 and D1, which stayed with him. From memory I am going to say it sounded similar to the PICO, when I was using it with the Mac Audio Midi set in 24bit/48Khz mode via optical out. Not quite as warm as a Predator, but powerful clear and neutral like the PICO.
PLANNED FOR THE FUTURE: I plan to try all 4 amps with several headphones this weekend, and will also try their analog inputs with my iMod and ALOaudio Jumbo Cryo Silver X LOD. Cheers, and happy listening!
...and sorry about your wallet!
UPDATE #1: I should mention that the RSA Predator takes a huge amount of time to burn-in. It wasn't so great sounding right out of the box, I mean it was good but not spectacular. By 300 hours it had gradually changed till it sounded nothing like it did fresh out of the box, and a veil was starting to lift. By 600 hours it was a whole new amp again, with real meat to the bass - and again this was via gradual slow changes (and not bouncing around like the D2 did). By 1,000 hours it seemed to me to be fully matured, with no changes between 1,000 and 1,100 hours. At that point, the Predator was shipped off to Skylab for his review in February.
UPDATE #2, 3/15/08 1:00AM: The D1 as I mentioned most recently had the AD743/LMH6643/LTC6241HV opamps in it. Previously it was warmer with more bass, and closer to the Predator, when it had the AD797/AD8397/AD6241HV in the LR/BUFFER/DAC opamps in place. That was before I rolled the opamps for the HFI-780. I suspect I'll be able to similarly tune the D2 and Lyrix which have socket opamps as well. I am not in a rush to do so yet.
UPDATE #3, 3/20/08 11:45PM - D2 VIPER STOCK MAKES POSITIVE GAINS AFTER 300 HOURS.
I have 311 hours on the D2, and I am now using my Woodied HF-1 with APS V3 cable at the moment, and all amps were driven by the USB DAC as before. So, I am revisiting it as promised with an extra 125 hours or so on it. I listened a lot on Monday and Tuesday with my Grados and Edition 9, and then took a 48 hour break while it burned in the final bit to reach 310 hours.
While the D2 initially had a very similar sound signature to the Pico, my 183 hour impression of the D2 was that the bass was a bit boomy and uncontrolled, and it seemed a little brighter than the Pico. Now the bass has indeed tightened up since the last time I listened on the 18th when I compared the amps with more headphones. Not only is the D2 bass now less boomy and more controlled, but the high's are a little smoother too (but maybe still a tad brighter).
With the extra hours on it, the D2 is clearly closer to the Pico than it is the Lyrix now, as the Lyrix DAC is seeming to hold it back now. But, there is that final bit of transparency and smoothness that the Pico holds over D2 still. I would say the top three amps are within a few percentage points of each other, when listening with the HF-1 APS re-cabled woodies. There is just something about warm full bodied sound of the Predator that keeps me coming back for more.
So, I give the Predator a 10/10. I'll give the Pico a 9.7/10 for opening the soundstage a bit and crisp detail, but with a cooler more analytical sound. The D2 has moved up from a 9.0 to a 9.4/10 for the D2 now, while still missing some of the warmth of the Predator and the final bit of transparency of the Pico. I have to give the Lyrix a 8.8/10 now. To me anything above an 8/10 is great but might not be a keeper if I have more than one amp sitting above 9/10.
I would put the D1 (with the newest round of opamps) right up there with the D2 now (sound is quite close), except that I got it back after 2 weeks with a channel imbalance, so I have to open it up and swap opamps and determine if the problem is my fault, or I have to contact iBasso. The right channel is louder using the DAC by a good 3db or more, but with the analog input the L/R channels are balanced. It currently has the AD743x2 in it for main, LMH6643 buffers, and LTC6241HV in the DAC.
UPDATE #4, 3/26/08 2:00AM - 2MOVE and MODIFIED D2 WITH NEW OPAMPS
I just spent the last 9-10 hours with all the amps, and a well burned in 2MOVE from Skylab. I first listened them all with the ALO modded HFI-780, but my current sinus infection must be boosting the vampire wire 780's bass a bit too much vs 7-10 days ago. So, I switched to my APS re-cabled RS-1 for more detail and layering, and more balanced bass, and listened to everything again. Having just gotten the APS re-cabled RS-1 and also re-cabled my Edition 9, it is an eye opener into hearing that the ALO modded HFI-780 are darker and bassier and less open at quiet volumes than I remember with the first part of the review (they do open up at higher volumes but louder make my sinus headache worse). Right now I am preferring the RS-1 and Edition 9 vs my 780's with 666 hours on them (don't laugh, that's how many hours they have
).
All Amps were reviewed as before, using only their USB DAC as source, via Macbook. The D2 was also tested with new opamps, with a LM6172 replacing the LT1364, and a THS4032 replacing the NE5532.
I used the same music as in the first test, but had to add a few more items: "Handel Messiah" conductor Christopher Hogwood, William Orbit "The Best of Strange Cargo", James Asher "Shaman Drums", Guinea Pig "Cool Cats", Jack Johnson. I also threw in various pop artists from my kid's music in 128kbps to test with poor sources.
The 2MOVE sounded closer to the Predator than the PICO, but with a little more treble extension and what I would call a slight midbass hump that I did not hear in the Predator other amps. The 2MOVE was what I would call warm and mellow - but not dark as it had a little bit more treble up top, in between the Predqtor and PICO (like the D2). The Predator seems to have a little better bass presence, especially helpful with the RS-1 which I feel are usually a little bass shy with bowls. The Predator's high end was also more suited to the RS-1 and HFI-780's which already have a strong treble presence. Bass and treble were not overpowering with any of the amps with the RS-1.
The 2MOVE was more forward and up front than the Predator or Pico, which didn't help the soundstage with Handel's Messiah when listening via the RS-1. The 2MOVE still has excellent ambience and detail of the large venue, but you are definitely closer to the choir. The Predator's bigger soundstage was itself beaten by the Pico by a small margin, which produced a more 3D Cathedral space. With one small studio recording (Tsuyoshi Yamamoto on FIM XRCD), I can almost hear the drums and cymbals echo off the walls with the 2MOVE, but that coloration does not appear to be there with any of the other amps.
The 2MOVE with piano and saxophone was sweet and seductive, like the Predator, where you could hear the warmth and the reedyness both at the same time. Where the 2MOVE also excelled was in acoustic music like Jack Johnson, like in "Badfish" on Look at the Love We Found, or "Times Like These" from the "On and On" album.
ALL the amps did electronic music well, like William Orbit, Chris Spheeris, James Asher. And ALL the amps are particularly ruthless with poor quality Mp3, revealing the poor dynamics and compression artifacts. With ALL of the amps I heard a grating quality with my kids' 128kbps pop/hip hop like Plain White T's. The Fray, Cartel, Avril Lavigne, Boys like Girls, Chris Brown, Wyclef Jean, Rihanna, Fergie, etc, which rubbed me the wrong way.
Back to the good stuff. What surprised me was listening to Diana Krall - the PICO just sounds more natural and transparent with songs from "Girl in the Other Room". This album gets included every time I do a review because it is mastered with some sibilance or harsh highs still remaining, so it makes a good test album to see how the amps or headphones handle it. While the Pico handles this the best, just above the Predator, I thought the 2MOVE was the most irritating of the amps with this partitcular album, and this hurt it's score. However, with the low-bitrate kid's music above, it was no more irritating than any of the other amps.
Now we get to the D2 with rolled opamps, using the LM6172 and THS4032 opamps, which would be about $25-30. The opamp change definitely changes the character if the amp, and it is less "Pico-Like" and more 2MOVE-like, except that it handles the one Diana Krall CD a little better/smoother, and it is slightly less forward, and the midbass hump is less. So, I guess that makes it more predator-like then?
The D2 does Saxophones VERY well now vs stock. It is like magic, wave the wand, and the D2 is transmorgrified into something else.
Having picked out the areas where one amp excels over the others, or falls behind the others, it makes it even harder to rank the top 4 amps. The Predator, 2MOVE and modified D2 sound the closest to each other's sound signature or flavor. While the Pico and stock D2 sound the closest to each other's sound signature. A similar sound signature is a "reminds me of" NOT a "sounds just like". That puts the amps in 2 camps, yet makes all the rankings fall between a 9.4/10 and a 10/10, and in my opinion too close to call based on sound alone.
The D2 with rolled opamps I feel is a little better than the 2MOVE, while the 2MOVE is better than the stock D2. So, my initial ranking has a tie for 3rd, and a tie for 4th...
1. RSA Predator (good bass and soundstage, more body, organic, full)
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1)
4. D1 with rolled opamps (AD743 main/LMH6643 buffer/LTC6241HV DAC - powerful, punchy, energetic, alive)
4. D2 stock (thin in the middle, neutral with good bass,)
5. Lyrix (good frequency balance, lacking details and air vs the others)
6. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant)
Quote:
UPDATE - 05/06/08 11:50PM: 7 USB DAC AMPS - ADDED HR Micro Stack Portable
(1) The Headroom Micro DAC and Micro AMP, 2006 version, AKA HR Micro Stack portable:
The HR Micro Stack came into my possession the first week of March, and I initially considered including it in this review, but I wanted to focus on the newer smaller combination portable USB DAC/amps first. Headroom now has a 2007 Micro portable DAC/Amp for $598; but the DAC chip is different, and they admit that the new Analog Devices DAC is a slight downgrade from the 2006 portable with Cirrus Logic CS4398 chip (they claim the 2007 desktop Micros with the CS4398 are still as good or better, but without 9v battery power).
This is a fairly large (for portable) two-piece set, with a separate DAC and matching Amp section. When strapped together with the optional Micro-Strap they act as one large unit and take up a 3W"x4D"x3H" piece of desktop. That is bigger than the iBasso D1, so it certainly wont fit in your pocket (not even a coat pocket), and is really what I would call transportable. Even worse, this means you get two medium-to-large sized power bricks, with proprietary connectors on the amp and DAC side, and no internal charging circuit. You have to buy a separate battery charger, and the one I have can only do two 9v at a time. Yikes. I haven't tested battery life, but I have read tales of the amp chewing through a pair of 9v re-chargables in 8 hours, and the DAC lasting maybe twice that. I will try to test out the 9.6v re-chargables that HeadRoom sells soon. See a recent previous post for battery life of the other amps reviewed.
I now have about 400 hours on the Micro Stack, about half from just regular use of music and not running it 24/7 after the first 180 hours. And I just feel that I need to add this to my review, and to let people know what to expect if they buy a used one down the line. There are a fair number of these out there, and they don't go up for sale used very often, and there is a good reason for that - they sound good.
I did my comparison against the Pico, and planned to pull out one of the other amps should the Headroom fall above or below the Pico, but I made a lucky guess and found them to be fairly equivalent. I used all the same program material, and listened with my RS-1 and D2000 (my HFI-780 were with mrarroyo at the time).
The HR Micro Stack via USB reproduces vocals and real acoustic instruments well, with no colorations and drop outs. Diana Krall was smooth, without sibilance, but female vocals and saxophones were just ever-so-slightly cooler than I like. Pianos were sharp with quick attack and smooth decay, and were not piercing. The sound does not seem boosted or sucked out in any areas.
There is a nice sense of ambience and space around the instruments, without making the venue sound cavernous (or microscopic). Rather, it is just right. With classical music I dare say it can recreate the large hall ambience slightly better than the Predator, and it reproduced the Cathedral-sized venue for Handel's Messiah as well as the Pico did. With smaller nightclub venues, and studio recordings, the ambience and dynamic range was good as well. I did not hear the sound of the instruments or the echos disappear too fast like with the Lyrix USB DAC (or Travagans Green).
Switching to optical digital, I can hear slightly better air and ambience with Headroom's optical input and my Macbook. I should note that while optical is a little more transparent, the USB performance is still pretty darn close to optical. Even when playing native 24/96 program material from Linnrecords.com Hi-res downloads, and setting the Macbook optical output to 24/96, the differences in sound between the HR optical input and the USB input of both the HR and Pico were fairly small (maybe a 5% improvement).
So, what about all my previous postings about the Micro Stack being a warmer and more musical setup, if it really sounds like a Pico? Well, I use the Micro Stack with crossfeed switched on 90% of the time. And the HR Micro Amp's sound warms up when you hit the crossfeed, even more than the Lyrix does with crossfeed. Whether it is better that way depends on the listener, the source, the program material and the headphones. With crossfeed off, there is very little difference in sound between the Headroom Micro Stack via USB and the Pico via USB. However, the HR Micro Stack is just a bit richer in the mids than the Pico when crossfeed is on, but also sounds slightly rolled off in the highs with crossfeed (more rolled off than the Predator). To my ears, the Lyrix and HeadFive tend to lose a little of their air and ambience when crossfeed is on; but the HR with crossfeed still seems to retain decent space and ambience, despite the slight rolled off highs.
Basically, via USB the $598 HR Micro Stack's performance and sound signature were similar enough to the $499 Pico to call it a draw. But, the optical S/PDIF digital input adds a small additional layer of ambience and transparency to the sound. The trade-offs for the gains with optical are bigger size, inconvenience of recharging batteries externally, out of production and higher cost. This is great for my iRiver and Sony portable CD Player with optical at the bedside. But if you are putting together a computer only rig and just wont use the S/PDIF inputs, then there are better choices reviewed here that will give you great sound in a smaller and more convenient package. If you need the crossfeed on a computer-only rig, get the 2MOVE - although it's affect was more subtle than Headroom or Headfive, it did not seem to affect the sound signature much, or cause a roll-off in the highs.
(2) Some notes about the Lyrix Pro USB Total, Lyrix Pro (and it's little brother the Caffeine Pro):
I've had several inquiries about the Lyrix, whether it is the DAC or the Amp that holds it back. I believe it is the DAC that holds it back, even though the DAC sounds better than headphone out of a 5.5G iPod or Macbook (which not surprisingly sound similar to each other and could use improving). It also confirmed for me how important burn-in is with these small amps, as I got to compare a new vs 500 hours side-by-side.
Let me preface by saying the Lyrix Total Pro needed about 70 hours burn-in to open up and smooth out, then about 200 hours burn-in to get to 95% of it's potential, and after 300 hours there were few if any changes to the refined smooth accurate sound they produce. Interestingly, I couldn't hear much change when flipping on the crossfeed when new out of the box, or even in the first 70 hours. By the time I had 200 hours on it, the effect was more audible. Other people have reported the same findings with the Lyrix crossfeed vs burn-in.
When I got an extra Lyrix Pro for my son a couple of weeks ago, my Caffeine Pro (basically the same amp) and Lyrix Pro USB Total had over 500 hours each. In comparing the new one I could hear the constriction in soundstage, less warmth in the lower mids, and a slight coarseness in the highs. Now, at 150+ hours it is pretty hard to tell the differences between Lyrix Pro and the Caffeine Pro, while there is still a slightly more refined quality to the sound of the Lyrix Total. The warmth in the lower mids doesn't seem to develop in the Lyrix till after 150+ hours of burn-in, and while it is still a little behind that of the Predator, Pico, 2MOVE or Headroom, the amp section by itself is close to the HeadSix and still ahead of the stock iBasso D1 or D2.
(3) Because of all the questions about whether the main differences in my review are from the DAC or the Amp section, after I got my D1 back from iBasso I briefly listened to most of them with analog input from an iMod, instead of via USB DAC. (except the 2MOVE which I don't have)
People keep forgetting how close they are already, as I've said many times, and I love them all. There isn't a big difference between an amp rated 9.4/10 and a 10/10 (which is where most of them sit). So, as expected the sound quality of most of the amps via analog input is just as close as when using their internal DAC (the exception is the Lyrix amp-only is now better than a stock D1 or D2).
Although their basic sound signatures remain mostly unchanged, using the same source (the iMod's DAC) slightly lessens the differences into just their own essence or flavor, what we call sound signature. The differences in sound quality would still be in the single digit percentage points, and subject to personal preferences (except the stock D1 with analog input is not terribly impressive - it really needs the DAC or new opamps to wow you).
Newest Ranking 05/06/08:
1. RSA Predator (good bass and soundstage, more body, organic, full)
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1)
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off)
4. D1 with rolled opamps (AD743 main/LMH6643 buffer/LTC6241HV DAC - powerful, punchy, energetic, alive)
4. D2 stock (thin in the middle, neutral with good bass,)
5. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great)
6. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant)
Newest Ranking 05/12/08:
Today I had to change opamps in the D1 in order to ship to someone, and I needed to rob 4 screws from the D2 temporarily (a long story), so while the D2 was open I returned the D2 back to stock just for a quick listen. So, I compared the D1 with AD797 main, LMH6643 buffers, and LT6234 in the DAC vs the stock D2 with LT1364 + NE5532.
The D1 with the above opamps is clearly better via USB than the stock D2, so I changed the rank from the stock D2 tied with the modded D1 for 4th, and moved the stock D2 to 5th place. The D1 with the above opamps is so good that it almost ties the Pico and HR Micro Stack for 3rd, but not quite (however via optical it might move up).
1. RSA Predator (good bass and soundstage, more body, organic, full)
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. 7/5/08: With my IEM I found it sounded best with the LM6172 and THS4032 swapped and the LM6172 in the ground channel. With the LM6172 in ground, the THS4032, AD8397, ISL55002, and LM1364 all sounded good in the main socket, although the LT1364 is slightly rolled off in the highs this way. This second option was good with all my full size except RS-1 seem a bit bright.)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1)
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off)
4. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241)
5. D2 stock (thin in the middle, neutral with good bass,)
6. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great)
7. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 6th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 7th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
Newest Ranking 07/31/08: Added iBasso D2 Boa. Comments below in Red were added 8/11/08.
I received a D2 Boa from iBasso and gave it 300 hours of burn-in like the Viper needed, and then I have used it another 20 hours for music over the past week listening to music. I listened with my Proline 2500, D2000, RS-1, Edition 9, Livewires, Freq Show, Klipsch Image and Sleek SA6. I compared it to most of the amps from before, except I do not have the loaner 2MOVE, or my iBasso D1 or Lyrix Total Pro any more. However, my Lyrix Pro with USB DAC Cable sounds the same as the Lyrix Total Pro, so I can use that for comparison if something is close in rank to it. The Boa was high enough in the ranking that I didn't need to bring out the Lyrix.
The Boa is a pleasant amp to listen to. As far as timbre and tone and frequency balance it is certainly better sounding than the stock D2 Viper to my ears. It does not sound as hollow in the mids as the stock Viper, so the Proline 2500 for example sound better with the Boa than with the Pico or stock Viper.
Listening to the saxophone in Tsuyoshi Yamamoto "Somewhere over the Rainbow" it had the pleasing warm-breathy and reedy-air sound at the same time, just the way I like it with the Predator, modded Viper, and 2MOVE. However, listening to Diana Krall "Temptation" I noticed that the lower mids seemed to be a little over-emphasized in her voice. With many of my headphones, the Boa could be a little too forward in the 250Hz range and could make pianos resonate a little in my ears. Because of this I did not like the Boa with my Freq Show customs or Klipsch Image as much as the other top three amps, but it was still acceptable.
With string bass, the D2 Viper with LM6172 in the main amp produced noticeably more powerful bass with much better impact. However, vs the stock Viper opamps I felt the bass was similar. The treble in the Boa seemed slightly less extended than the Viper, Pico or even Predator. However, at times the highs could seem smoother than with the Predator, which sounded slightly more aggressive when listened to side by side.
The Boa seemed to be lacking some of the transparency found in the the 1st-3rd place amps, as the air and ambience hasn't fully developed yet to what I think it's potential could be (based on what I hear in the Viper). I am hoping that this will get better with more hours, as the other top amps have 500-2000 hours on them. It is fairly transparent, but just not quite to the degree of the others, and this is still the case when fed by my iMod and Vcap dock. However, the Boa did open up and gain more air and ambience, to approach the level of the other top ranked amps by 575 hours of burn-in.
The Boa also seemed to have a slightly smaller soundstage than the other top amps at first. With the D2 Viper opamps swapped to the THS4032 in the main amp, the Viper has the most air and space to the musical venue, followed by the Pico and then the Predator, with the Boa somewhat behind those but catching up to the size of the Predator's soundstage by 575 hours of burn-in. Even with the more forward sounding LM6172 in the Viper main amp section, the size of the soundstage was slightly bigger than the Boa until 575 hours, and similar to the Predator.
Some last thoughts. I briefly tried the Boa with my HD600 and Yamaha HP-1 orthodynamics and wished for a little more power, but it was usable - but with the 600 ohm AKG K240M forget about it. There was no problem driving any of my other headphones. The USB charging feature is a major plus for the Boa, as is the doubled battery life vs my Viper.
I would take the Boa over a stock D1 or D2 Viper or Headstage Lyrix. If it wasn't for the extra power and optical DAC of the Headroom, the Boa might have placed above that too. Lately I have been using the Predator the most with my 3G Nano, the Viper with my iMod and IEMs, the Micro Stack at my bedside, and the Pico with the laptop but feeding it into other amps. Since the soundstage and transparency have developed and matured more over time with more hours on it, the Boa may well get used as much as the Predator, Viper or Pico.
Here is the ranking - see comments included: Comments in Red were added 8/11/08
1. RSA Predator (good bass and soundstage, more body, organic, full. Seems to do well with all my headphones, and not bad with any).
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. With my IEM I found it sounded best with the LM6172 and THS4032 swapped. This second opamp configuration was good with all my IEM, and not bad with my full size phones, except the RS-1 seem a bit bright and the Proline 2500 lacked fullness in the mids.)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1. It really seems to shine with my re-cabled Denon D2000, Klipsch Image, Freq Show customs, but doesn't sound bad with anything but my Proline 2500).
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off).
4. D2 Boa (Sonic signature slightly warmer than the Pico, and between the D2 Viper with LM6172 in the main amp (warmer) vs THS4032 in the main amp and LM6172 in the ground (cooler). Timbre and tone was good, and mids were slightly forward and rich, and highs had slightly less extension than the D2 Viper, Pico and Predator (in that order). The sense of space with live performances was superior with the D2 Viper, Pico and Predator (in that order), and LESS with the Boa at 300 hours of burn-in. However, the Boa did open up and gain more air and ambience on the level of the other top ranked amps by 575 hours of burn-in. Listening to Diana Krall "Girl in the Other Room" (Temptation and other songs) seemed to indicate more of a low mids hump than the other amps, which also caused problems with Pianos and realism on that CD. The problems reproducing this particular CD remained after 575 hours of burn-in, however with other CD's like Jazz at the Pawnshop, Handel Messiah and Tsuyoshi Yamamoto the D2 Boa demonstrated improved transparency and realism with the extra burn-in. And with other music it seems the bass extension is slightly less than the others in the top ranks, but by 575 hours of burn-in (with my RS-1) the 16Hz audio tones on Binks Audio Test CD were clearly audible, and the volume of the 20Hz tone caught me by surprise, while 25Hz was a little disorienting!
5. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241. The D2 Boa moved up a little with more burn-in, but it wasn't quite good enough to rise up to a 3rd place tie. So the modded D1 and everything else had to move down a slot. The D1 via USB isn't as good as via optical, which is why it is not tied with the D2 Boa once the Boa improved with extended burn-in.
6. D2 stock (thin in the middle, neutral with good bass - it was sound signature and not level of detail that held it back with the stock opamps.)
7. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great)
8. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 7th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 8th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
Newest Update 09/08/08: Added Vivid Technology V1 - long with pre-burn-in and post burn-in comments.
The Vivid Technology V1 USB DAC portable amp is an AD8397 opamp driven amp, with TL2426 railsplitter for ground, which is similar to the Headstage and Penguinamp choice. The DAC Chip is the PCM2704. The battery is 900mAH 3.6V, but the amplifier always runs off a boosted 5.5V supply. The Lithium Ion battery charger is a smart charger that stops charging when the battery is full. The amp always takes power from the battery in all cases (like the Pico), is trickle charged by the USB port, and can be charged 3x faster with the optional wall wart. I ran the V1 for 15-16 hours on battery via analog input and went to bed with it still running, and when I checked it after 22 hours the battery was dead. I get 15 hours from the stock D2 Viper (7-9 hours with various new opamps), over 20 hours with the Pico, over 24 hours with the Boa (never tried longer) and over 48 hours with the Predator (neck paid attention for longer).
The ABS case is 2.6"(66mm) x 2.6"(66mm) x 1.1"(28mm), so held next to the Predator and eyeballing it, it looks about 1cm deeper and taller, and about 1.5cm wider (still smaller than the Headstage). It fits under the 3G nano well, only sticking out about 4 mm on either side of the Nano when the nano is in a leather case. You can visit vividaudiotech.com - Headphone Amplifiers to read up on the specs and amp, and see pictures.
Here is the claimed power output of the V1 (using 1KHz tone, no THD specified) vs the Firestone Cute Beyond.
600 ohm - 50mW
300 ohm - 100mW
200 ohm - 150mW
100 ohm - 200mW
32 ohm - 780mW
16 ohm - 1.5W
Cute Beyond published power output:
600 ohm - 60mw (AKG K240M = 106 db)
300 ohm - 120mw (HD600 = 118 db)
120 ohm - 300mw (AKG501 = 119 db)
75 ohm - 480mw (AKG 270S = 119 db)
32 ohm - 320mw (Grado SR60/80 = 121 db)
This is an amp that clearly benefits from burn-in, and at 350 hours it will sound much better than it did out of the box. Taken from my notes on 8/23/08, using the MS-1 with the amp right out of the box, I felt the upper mids were just a little strident/prominent. It sounded punchy with good bass, good separation and detail, but soundstage somewhat was somewhat constricted. There was some obvious sibilance with Diana Krall "Girl in the Other Room" and a few other songs. The volume knob was around 11 o'clock for normal listening. Without any burn-in, even my Creative Xmod with 200 hours was smoother and more transparent/natural with bigger soundstage.
With less than 15 minutes on the amp and a 2 hour break, I came back and switched to the RS-1. The cymbals shimmer and hang with nice decay, but there is still sibilance on Diana Krall. The upper mids are still prominent but it is more transparent with the RS-1. With bowls bass should be a little stronger than it is, while flats improve the bass and sibilance but shrink the soundstage. Volume with RS-1 is now around 10 o'clock for normal listening, and I will never listen as loud as it gets at 12 o'clock. Trying some test tomes, out of the box the 20Hz tone is in-audible and missing, 25Hz okay, 31.5Hz strong. I had to EQ out 2 db at 2Khz, and 3 db out at 4Khz and 8Khz to fix the prominent upper mids.
At 40 hours of burn-in using 20 min pink noise alternating with 2 min silence I switched to HD600, which adds about 1 hour to the volume knob and I have it at 11 for normal listening and 1 o'clock for very loud music. The sound was nice and warm but clear, crisp and detailed. The HD600 really sounds better with the V1 than with my earlier tests with RS-1 or MS-1. At 60 hours with HD600 I notice a big jump in bass, almost too much midbass, but at the same time it is a little smoother upper mids too. With that kind of change, I decided to wait until the DAC was burned in at the halfway point thru the 300 hour recommended burn-in before listening again. At 164 hours with the RS-1 again, I was able to reduce the EQ settings in half vs the out of box EQ settings above. I then moved it over to my iRiver to finish burn-in via the analog input as recommended by the manufacturer, who stated the DAC and anolog inputs use different circuits and I should split the 300 hours between them. (note: I have over 2000 hours on Predator, over 1000 on Viper, over 600 hours on Pico Boa and Micro Amp and Lyrix with USB DAC Cable, and 350 on V1 for the review).
By 9/7/08 the V1 has 350 hours (164 on DAC), and I am ready for listening. Since it is not quite up to the level of the Predator, D2 Viper with rolled opamps or Pico, I returned the D2 Viper to the stock opamps for the comparisons. The day before I had run the test tones again with RS-1 to compare to out of the box results, and 20Hz is now clearly audible on the V1 while 25Hz is only slightly rolled off vs out of the box where it was not as good. The Pico and Predator are audible to 16Hz, and have more energy at 20Hz than V1, with D2 Boa slightly behind those. The V1 bass extension is similar to the Boa and superior to the stock D2 Viper which is noticeably rolled off at 20Hz. After testing the bass extension with the RS-1 vs out of the box, I had to take a break for my daughter's 15th birthday and come back the next day to start listening to music, so I burned it in an extra 24 hours.
I started with the HD600 and stock cable and found that the tonal balance and Timbre is nice, with good bass, mids and treble. There is no boosted bass, just flat and extended and almost as strong as the Predator but not quite. Certainly no lack in bass, and not bass light. With Infected Mushroom "Dancing with the Kadafi" the bass is rockin', punchy and hits hard. That was my first WoW! moment with the V1 amp (goosebumps and all when I was at 164 hours), which is why I chose to start with HD600. Switching to string bass, it is not supposed to hit hard and it sounds like it should - crisp and quick and present. So it isn't over-boosting the bass levels but it is bangin' when it is supposed to be.
Mids are rich and warm, and not very peaky or resonating in the ears or head, although there does seem to be a mild low mids "boxy" coloration that is very similar to that of the D2 Boa, especially with close miked female vocals. This makes some female vocals like Shelby Lynn in "Just a little Lovin" or Diana Krall in "Girl in the Other Room" sound slightly artificial or less transparent vs Predator/Pico/D2 Viper/HR MicroAmp. Similar to the D2 Boa, I have a hard time noticing this coloration with acoustic and wind instruments or electronic program material, as it's mostly only an issue with vocals. And, this is not with all vocals - switching to Herbie Hancock "River:The Joni Letters" with Nora Jones singing the first track, her voice seems more natural with both the V1 and D2 Boa, and male vocals like Jack Johnson "Sleep Through the Sttaic sound fine with them too.
Treble has a nice sparkle, shimmer and decay to cymbals, and pianos have a sharp quick attack but do not drill into the head. With HD600 the V1 does not accentuate the sibilance present in the Diana Krall recording above, which is a test album I use for that purpose. I also use the "Girl in the Other Room" to test for lower midrange coloration as Diana Krall is very close mike'd and it is easy to push the lower mids over the top as above (which is exactly what I heard).
The soundstage is similar to the 2MOVE, not too close and not too distant, although it is somewhat more forward than the Predator (making it closer to that of the 2MOVE). It is certainly more forward sounding than the Pico, D2 Viper and D2 Boa or HR Micro Amp, while the other amps have a larger more open soundstage vs the V1. Listening via the USB DAC for the entire review, despite being somewhat forward sounding there is still a good sense of space and ambience - but there is a little less transparency than with the Predator or other amps, like watching through a clean window instead of an open window. It does seem to be a little more micro-detailed than the Headstage Lyrix USB DAC or iBasso D1 USB DAC were. The V1 DAC is also not as smooth sounding as the Pico (or the other amps to some degree), but I wonder how much of that is the Pico and other amps being less forward and not having the slightly more pronounced upper mids (2KHz-8Khz) of the V1.
A nice loud but enjoyable volume level setting with HD600 and the Macbook is about 11-1 o'clock, depending on the program material. I find listening to most music at 2 o'clock is too loud for me, and 3 o'clock just starts to clip a little with no change going higher than 3 o'clock. Again, I would likely never want to listen loud enough to clip with HD600. The V1 has no problem driving the HD600, and the same volume at 11 o'clock with the V1 needs 1:30 o'clock in high gain with the D2 Boa. 5 o'clock (max) on the Boa is like 1:30 - 2 o'clock on the V1, and it sounds like the V1 can double the power of the Boa by 3 o'clock (sounds a good 3-4 db louder). On quiet classical music with wide dynamic range, this is a big plus over the Boa and stock D2 Viper.
This amp really seems to have some nice synergy with the HD600, and for $99 is a screamin' deal for you HD600 owners. It makes the HD600 sound good with all types of music - even if the Predator and Pico are a little better, they may not be $400 better for many people. The D2 Viper with rolled opamps and 2MOVE and Micro Amp are also slightly better with HD600, but still 2-3x the cost. This is a $99 amp that competes well with $170-180 amps driving HD600 (Stock Viper, Boa and Headstage). But switching from HD600 to the RS-1 (APS V3 cable and bowls) while I was listening to Jack Johnson is where those prominent uppers mids (2KHz - 8KHz) become more noticeable. After a few hours with the HD600 and stock cable, switching to the RS-1 with APS V3 cable was almost a shock to me.
As mentioned before, with the V1 fresh out of the box and driving the RS-1 I had to EQ out about 3 db at 2, 4 and 8Khz, but with the stock HD600 I needed NO EQ. After 164 hours of burn-in I had found that the amount of EQ needed with RS-1 and bowls had decreased to only removing 1 or 1.5 db at those frequencies, which is when I switched to burning it in without the DAC (so no EQ). Hoping to be able to make due without any EQ, I decided to get my ears acclimated to the RS-1 by listening to only the RS-1 for a while. I also switched to some non-vocal jazz music again - Guinea Pig "Kool Kats".
This was much less glaring, and the sax, trombone, trumpet, bass, drums and cymbals sounded much better and I could enjoy it with no EQ at all; although the EQ would bring it more in line with the other amps. Switching to Tsuyoshi Yamamoto "Smooth Jazz Festival" 'Somewhere Over the Rainbow' had the saxophone sounding a little edgier than the Predator, Pico or Boa until I applied the EQ again, although I could enjoy it without EQ. Pianos on this Tsuyoshi Yamamoto were not quite as enjoyable without the EQ as the other music. Moving back to some vocals with Shelby Lynn "Just a Little Lovin" (once my ears were acclimated) I found it sounded better with no EQ. But Jack Johnson still sounded a bit edgy. Most Jazz and Classical as well as electronic and new age sounded fine with the RS-1 and bowls driven by the V1, and for those albums that didn't sound their best, using the mild EQ brings them into balance and then it sounds very good with RS-1.
A light bulb went off in my head, and I switched the RS-1 back to flats like I tried whn out of the box, and voila - much better! This also helped somewhat with the lower mids coloration that I heard. I definitely prefer using the Grado flat pads with the RS-1 and V1 amp, which reduced ANY need for EQ of the upper mids. At this point the RS-1 became much more enjoyable with the V1, and it was almost up to the level of the D2 Viper and Boa with the RS-1, but not quite. Jack Johnson was now pleasant with no EQ. Even with the flat pads, many classical recordings such as "Handel's Messiah" still retained a good sense of space and ambience, despite the smaller soundstage with the flats. In doing the volume comparisons using RS-1, I found that a volume setting of 11 o'clock on the V1 with Infected Mushroom corresponded to a 1 o'clock in high gain on the stock D2 Viper. 12 o'clock was quite loud and rockin' with the V1 and electronica!
Switching to the Ultrasone Edition 9, the V1 was back in its element again, and paired well with these headphones. I enjoyed the V1 with the Edition 9 as much as I enjoyed it with the HD600, although I noticed the Pico has more bass with the Edition 9 than the V1, as did the Predator, D2 Viper and Boa. A little experimentation showed me that I can play the V1 louder with the Edition 9 without being over-whealmed with bass (which is easy for me due to my chronic tinnitus, which wasn't helped any by firing a firearm at a charging bear two weeks ago). However one of the advantages that the Edition 9 have over other my headphones is not having to play them loudly to get a good frequency response and liveliness. With Edition 9 and some music like Infected Mushroom "Dancing with the Kadafi" from the B.P. Empire album, I thought the V1 was better than the Pico, but with live jazz and classical music on the Edition 9 I found the Predator and Pico were the best again, followed by the Micro Amp and the two D2 amps. I don't have the loaner 2MOVE to compare, and didn't have time to roll the D2 Viper opamps again.
Typically with the Edition 9 and Pico, Viper or Boa the normal listening level is with the volume knob at 10 o'clock in HI gain, and it is at 9:30 with the V1. The Predator HI gain with Edition 9 puts the volume knob at about 9 o'clock! As a point of reference, medium gain on Predator puts the volume at 10 o'clock and low gain puts it at 12 o'clock.
I do not have my Denon D2000 while they are being re-terminated as balanced 4-pin (with SE adapter), so I tried my 600 ohm AKG K240M that used to be owned by Stevie Wonder (eBay seller bought them from his ex-wife, and he was selling all kinds of stereo equipment and DAT with brail dots on them, and they smell like his hair gel
). Anyway, these are quite difficult to drive. Moderate and good volume levels can be obtained at max volume without clipping the V1 (5 o'clock). The V1 can play much louder with the AKG K240M than the stock D2 Viper, which I maxed out in high gain at 5 0'clock and still found the D2 Viper to be about 5-6 db quieter. The D2 Boa was maybe 1-2 db louder than the Viper with these 600 ohm AKG, but it still couldn't attain the higher levels of the V1 when at max volume. The Predator in high gain at 3 o'clock could beat the stock Viper volume and match the Boa in volume, but it would clip at anything past 3 o'clock with the 240M. Only the Pico could exceed the V1 volume levels with these headphones, by at least another 2-3 db! With the Pico and V1, maybe 10% of my music had a high enough input signal to make me back down the volume knob by half an hour from max volume to avoid clipping. And, transparency with the AKG was quite good, possibly even better than with the HD600 which were previously my favorite with this amp! (although the bass is not as strong as the HD600). All the amps were very transparent with the AKG K240M and these are great headphones, but only the Pico and V1 could really do them any justice without resorting to a desktop amp, with the Pico still a clear lead. Wow again, to be in second place with these headphones was a big surprise!
Next were IEM. I switched to Klipsh Image X10 IEM which can be a little harder to drive vs my high sensitivity Custom IEM's. The volume for normal listening was 9:30 on the V1, and by 10 o'clock it was moderately loud volumes and higher than I typically listen at. 11 o'clock was louder than I will ever use, and clipping started at 12 o'clock with extremely loud volume levels. I hear no hiss with music paused until I get past 10:30 o'clock, so it isn't likely that I will ever hear hiss between songs when listening to the Image at loud volumes. With analog input and the music paused I don't hear any hiss until 11:30 o'clock (using iRiver H140). The power switch is built into the volume knob, like the Pico and Ibasso D2 amps, but there is less channel imbalance at low volume settings in the V1 vs those other amps - so I can play it very quietly with the Image X10 without problems, like when going to sleep or for background music. The D2 Boa could not play the Image quite as loud, and was clipping in low gain by 2 o'clock. I thought the V1 had good synergy with the Image X10, and was very enjoyable - tight strong bass, warm mids, crisp sparkly highs (using shallow insertion of the Image into ear canals). The lower mids were a little more pronounced with the Image on vocals than I liked, but were acceptable.
Last ones to try were my Freq Show custom IEM, which are so sensitive that I actually hear music with the V1 volume all the down and just above the power-on setting! I turned up the volume to 10:30 and heard hiss with the music paused, and backed down to 10 o'clock where the hiss went away. I un-paused the music and was blasted out of my skull by the loud music! I will never listen to the Freq Show at 10 o'clock, with 9 to 9:15 o'clock being a normal listening level and 9:30 to 9:45 is fairly loud. Again, I can play them very quietly without a channel imbalance, but not as quietly as I could the less sensitive Image. Still, it was acceptable for low level "go to sleep music" volumes.
The sound with the Freq Show was not bad with some music, very good with others, and a big problem with others - this being the fault of the IEM not the amp. Similar to the problems with using my Freq Show with the Meier Headsix or D2 with LM6172 opamp, vocals like Shelby Lynn "Just a Little Lovin" or Diana Krall "Girl in the Other Room" had the lower mids too pronounced and caused my ears to ring and roar. For those of you whom have read my reviews linked in my public profile (about me section), you know that with my ears the Freq Show are very picky about amps, and I almost returned these IEM for a refund. A few other people have reported the Freq causing ringing and roaring in their ears as well, not just me, although it is a very small minority of people. For example, my Headsix (lo gain) is great with Livewires but I didn't like it with my Freq; while Germania loved her Freq Show with her Headsix, so I do think it is "ear" dependent with these IEM. I picked these IEM for the review because they are popular and are the most fickle ones I own in regards to which amp I choose. With the Jack Johnson "Sleep Through the Static" they sounded good, and with non-vocal jazz and classical music I also have no problem with the resonance and ringing, but some (not all) acoustic guitar and piano music would ring in my ears too.
Again, THIS IS A PROBLEM WITH MY FREQ SHOW, not the amp - but the V1 amp doesn't help the problem any. This problem being uncommon to other people made me decide that it will not affect it's ranking below. I usually have to use either my Pico or Predator, or D2 Viper with rolled opamps for these IEM, or I have to play them very quietly if I don't have the right amp available. That being said, at very quiet volume levels like 9:00 - 9:15 o'clock then Shelby Lynn or pianos do sound nice with the Freq. My highly sensitive Livewires custom IEM are out in my car and not tested, but they sound good with every amp I have tried so I have no fear using them with the V1.
NEW AMP RANKING 09/08/2008 - Adding Vivid Technology V1.
Here is the ranking - see comments included if you haven't read the entire review:
1. RSA Predator (good bass and soundstage, more body, organic, full. Seems to do well with all my headphones, and not bad with any).
2. D2 with rolled opamps (LTC6241HV/LMH6622 sounds like 98% of the Predator with 7 hour battery life. LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. With my IEM I found it sounded best with the LM6172 and THS4032 swapped. This second opamp configuration was good with all my IEM, and not bad with my full size phones, except the RS-1 seem a bit bright and the Proline 2500 lacked fullness in the mids.)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1. It really seems to shine with my re-cabled Denon D2000, Klipsch Image, Freq Show customs, but doesn't sound bad with anything but my Proline 2500).
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off).
4. D2 Boa (Sonic signature slightly warmer than the Pico, and between the D2 Viper with LM6172 in the main amp (warmer) vs THS4032 in the main amp and LM6172 in the ground (cooler). Timbre and tone was good, and mids were slightly forward and rich, and highs had slightly less extension than the D2 Viper, Pico and Predator (in that order). The sense of space with live performances was superior with the D2 Viper, Pico and Predator (in that order), and LESS with the Boa at 300 hours of burn-in. However, the Boa did open up and gain more air and ambience on the level of the other top ranked amps by 575 hours of burn-in. Listening to Diana Krall "Girl in the Other Room" (Temptation and other songs) seemed to indicate more of a low mids hump than the other amps, which also caused problems with Pianos and realism on that CD. The problems reproducing this particular CD remained after 575 hours of burn-in, however with other CD's like Jazz at the Pawnshop, Handel Messiah and Tsuyoshi Yamamoto the D2 Boa demonstrated improved transparency and realism with the extra burn-in. And with other music it seems the bass extension is slightly less than the others in the top ranks, but by 575 hours of burn-in (with my RS-1) the 16Hz audio tones on Binks Audio Test CD were clearly audible, and the volume of the 20Hz tone caught me by surprise, while 25Hz was a little disorienting!
5. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241. The D2 Boa moved up a little with more burn-in, but it wasn't quite good enough to rise up to a 3rd place tie. So the modded D1 and everything else had to move down a slot. The D1 via USB isn't as good as via optical, which is why it is not tied with the D2 Boa after the Boa improved with extended burn-in. With optical input would beat the Boa easily.
6. Vivid Technology V1 (very good synergy with HD600 and AKG K240M 600 ohm, nice and fun with Edition 9 and Klipsch Image X10, acceptable with RS-1 IF switching to flats but bowls are not recommended, unacceptable with my Freq Show but not the amp's fault. DAC with slightly more micro-detal than stock D1 via USB or Headstage Lyrix, slightly less than either D2 Viper/Boa or the other amps. The most forward of all the amps. Can be near 3rd or 4th place with HD600 and 2nd with K240M, but 9th place with Grado RS-1 and bowls.)
6. D2 stock - tied (thin in the middle, neutral with good bass - it was sound signature and power but not level of detail that held it back with the stock opamps.) Sounds good with Freq Show and most of my IEM, fairly good with HD600 and Edition 9 but lacks power, not bad with RS-1 but can't properly drive AKG K240M 600 ohm. Sounds better with re-cabled modded ATH-AD900 than the Boa or V1.
7. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great with analog input.)
8. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 7th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 8th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
11/1/08 - iBasso D3 Python added:
I received the iBasso D3 Python review sample on 10/15 and started the burn-in right away, to reach 300 hours and do my review. I have used some popular headphones and the top 4 phones all have APureSound cable on them, including Grado RS-1, Denon AH-D2000, Sennheiser HD600 (silver mesh) and Ultrasone Edition 9. I also tested with Livewires custom IEM, and Klipsch Image X10 IEM. It sounded fantastic with everything, even right out of the box. Without any burn-in it sounded as good as my 1500+ hour D2 Viper with LM4562 opamp in the main socket and LM6172 in the ground.
I used 5xAAA Energizer batteries in the D3 and I got 123 hours out of the batteries before they became too weak to play loud without distortion today. The next set last 113 hours. The third set was Rayovac Hybrid NiMH long lasting re-chargeables which went over 96 hours on a charge (it was still running strong at 96 hours at 2am even though the LED had become dim, and it was dead at 10am when I got up). During burn-in I used my Denon D2000 with a pillow between the ear cups and listened intermittently each day, without a lot of changes during that time. I just finished charging the batteries, and with 332 hours on the D3 I am starting my review (10/29/08).
My first listening had been with Denon D2000 and this was the first time to try the Grado RS-1 with bowls, so I started there. I had previously compared the D3 Python out of the box vs my D2 Viper (see above) and felt I could not tell which was which with my eyes closed, so this time I started my comparison vs the D2 Boa (while the Viper and Predator are being charged). I put on some Shelby Lynn "Just a Little Lovin" and felt that the D2 Boa sounded nice. After 3-4 tracks on the Shelby Lynn album, I switched to Guinea Pig "Kool Cats", and Tsuyoshi Yamamoto "Smooth Jazz Festival", Jazz at the Pawnshop, Handel "Messiah", Arvo Part "Tabula Rasa", Sibelius (assorted), Infected Mushroom "B.P. Empire", We the Kings "We the Kings", Metro Station "Metro Station", and Jack Johnson "Sleep Through the Static". After that I just randomly picked music from my library that I wanted to hear.
Switching between the D2 Boa to the D3 Python produced a noticeable change - the soundstage opened up a bit and became bigger, and the highs brightened up a little. The D3 Python seems a little more clear and sparkly than the D2 Boa. The third thing I noticed was the D3 Python's seems a little more solid and focused than the Boa. This not to say the D2 Boa doesn't have treble presence or good bass, just that the D3 Python is better. The next thing I noticed was the D2 Boa at 800 hours has lost a little more of the lower mids hump that it used to have in female vocals - this brought it up to being less colored than before, and closer to being neutral like the D3. If you recall from previously, it took 600 hours for the Boa's soundstage to open up as much as it did, and it was still changing for a long time like the Predator which took 1000 hours - so it is reasonable to me that the D2 Boa sound has further improved with time. On the other hand, the D2 Viper only took 300 hours to fully burn-in, and the D3 Python seems like it needed even less time. Nevertheless, the D3 is an upgrade over the Boa in the areas I mentioned.
Next was comparing the D3 to the Pico, still with the RS-1. Now if you have read all of my review from the beginning, you will see that while I gave the Predator a slight edge in personal preference, I have always said the Pico was very good and I enjoy it (9.7/10 vs 10/10). I have also posted in another thread that the Pico's sound had become warmer after I put an additional 300-400 hours on it, after Asr had owned it and broken it in already. Most recently I had decided that I now like the Pico as much as my D2 Viper with rolled opamps, and have been planning to move it up to a second place tie. It's still my favorite to use as a USB DAC Pre-amp to feed a full sized amp. So while comparing the D3 Python to the Pico with the Grado RS-1 tonight I thought the Pico was slightly smoother in the upper mids - but in regards to soundstage and air and ambience and micro-detail I think they are on a very similar level, with only the very slightest edge going to the Pico. The upper mids did not cause trouble with the RS-1 and rock music like I had found with the Vivid V1, so it was still enjoyable with bowls or flats won the RS-1.
Switching to the Denon D2000 I felt the Pico's advantage in the smoothness of the upper mids went away. I have previously said I really like the Synergy between the Pico and D2000, and I think the D3 has it there in spades too. With the D2000 I can tell that the two amps do sound a little different - the D3 bass was slightly less in quantity than with the Pico (like maybe only 1 db), but maybe it was a little more taught with the D3 Python. Again, the soundstage remained open and airy with good detail; and with both amps and I could place Shelby Lynn and the various instruments on stage - same with other pieces like Jazz at the Pawnshop where the D3/D2000 combo was very transparent with excellent soundstage and instrument placement. Interestingly I was then surprised with some classical music where I found it a little bit too wide, where sometimes I felt the result left a hole in the middle (Sibelius: Finlandia, En Saga, Karelia Suite, Etc.). This didn't occur with the D3 and RS-1 or D3/HD600, or with the Pico and D2000 where I found a more cohesive soundstage from ear to ear with no hole. With Arvo Part "Tabula Rasa" the hole was much smaller in the center of the soundstage but not entirely gone. With Handel: Messiah the hole went away completely with the D2000, just by changing the program material. Since the issue wasn't apparent with the D3/RS-1 or D3/HD600, it is also possible that it's the fault of the D2000 since I haven't done the markl mods and stuffed the earpads to tilt the cans and drivers more. I would again put the D3 and Pico on about the same level with all my other program material, as it was difficult to find any other material that gave a hole in the soundstage with the D2000. One other test I ran was test tones since the D2000 has such excellent sub-bass, and the D3 has solid bass down to 20Hz with the D2000 (and 16Hz is audible).
Listening with the HD600 the D3 had good synergy and sounded very similar to the Pico again, and it has plenty of power to drive them to high volumes as well. The power output with these 300 ohm cans is very good, and better than the Predator and D2 Boa in terms of sheer clean volume. The power output with HD600 is very similar to the Pico and Vivid V1. I found nothing to complain about with the D3 and HD600, and would be happy to listen to the combo anytime. Female and male vocals are still very good like with the other headphones, and I liked the D3 with all genres out of the HD600. The bass was powerful but detailed, the mids smooth and the highs sparkly, just the way I like it. The D3/HD600 was just as exciting with Infected Mushroom "Dancing with the Kadafi" as with the Pico and V1 in my earlier reviews, and I could achieve the same volume levels with the D3 at 4 o'clock as the Pico at 3 o'clock, but past that either amp would start clipping. With the HD600 the D2 Boa was well behind in volume and punch, with at least 4-5 db less output. There were NO soundstage defects with the HD600, and the soundstage was centered in front of my forehead and running from in front of my head to inside of my head, and width was good as well. Again, this was reminiscent of the Pico soundstage. However, the Pico does still seem be a little clearer in the ambient cues and very slightly more detailed in complex passages.
With the Edition 9 I was really impressed with the D3 - it does a good job controlling the bass and defining it like with the D2000, so it doesn't over power the rest of the sound spectrum. It was clean and alive sounding, and very quick and punchy. Soundstage, tone, transparency and frequency balance are all a good match for the Edition 9. Normal listening levels were at 10 o'clock and it could play very loudly at 12 o'clock, reaching the same volume levels that I would achieve with the HD600 maxed out at 4 o'clock! Clipping would not begin until past 2 o'clock with the Ediiton 9, at volume levels much higher than I could ever use, and I could feel my ears and jaw shaking at max clean volumes - thank God for the ear plugs! The Pico still manages to out-power the D3 with Edition 9, by probably a noticeable 2 db louder, even though they could both play to the same volume with HD600.
The last ones to try were some IEM. I felt the D3 was very good with my Livewires, SE530 in Custom Shells, Freq Show and Klipsch Image X10. However, I could easily hear that the D3 is picking up some RF interference from NORAD and Cheyenne Mountain that are in my backyard, along all the local radio station towers are up the mountain too! I could actually hear FM stations being picked up by the D3, which made it very difficult to use with IEM and USB. With my iMod or analog input there was no such RF interference, and it only occurred with a USB cable plugged into the back of the D3, even if not connected to a computer. And it was only heard with headphones plugged into the amp when the amp is turned on, but not heard in the DAC line out. I had a similar problem with my Meier HA-1 Mk2 headphone amp, but only with headphones plugged into the low impedance headphone jack, and sure enough this RF improves in the basement like the HA-1 did when I moved it there. I will be taking my amps to a Colorado Head-fi meet Saturday 11/1 in Denver, and will listen again for any RF interference, but I'm pretty sure the fault is Cheyenne Mountain - because of them we had to change all of our garage door frequencies because NORAD was blocking the remote door openers.
Fortunately it only occurs between 8 o'clock and 9 o'clock on the volume knob, almost like the D3 uses an active volume control. And it gets better in some parts of the house where the radio towers that are on the mountain behind my house don't seem to reach as well. I hadn't noticed it before because I was only using the volume between 9-12 o'clock to listen to music with full size headphones. None of my other amps pick up radio stations, but the D3 Python and D2 Viper are also very susceptible to chattering from my iPhone if it is anywhere near the amps.
Finally - Ranking, with a caveat: I want to first clarify a little about some changes my personal tastes and preferences. One big area that is becoming more important to me over time is not just having those rich warm seductive mids for vocals and saxophone or other acoustic instruments, but also having good transparency with larger soundstage and good ambience and space, ALL AT THE SAME TIME. My home amps have spoiled me and I am becoming more demanding in my expectations as well.
Summarizing what I was thinking previously - The 2MOVE that I initially ranked slightly above the Pico was very detailed and warm and rich. But it lacked some space and air or ambience vs many of the other amps, creating a more forward intimate setting that I REALLY dug at the time I reviewed it. Some of this soundstage was due to the amp section itself, as feeding it with a better DAC still felt more close and intimate (just not quite as much). I do not have a 2MOVE anymore to compare to the D3 DAC, but I do have most of the other amps that I previously compared the 2MOVE against. Having listened to all of them again (except 2MOVE), I think that at this point I am happier with the Pico than I would have been if I had owned the 2MOVE. As a matter of fact, I haven't used my Meier Headsix in months, which has a similar sound signature and soundstage as the 2MOVE. I have been using the Predator, Pico and D2 Viper the most out of all of them.
Now, the Predator via DAC was more spacious than 2MOVE, while the Pico would project an even bigger more spacious and airy soundstage above and beyond all the others. The D2 Viper with the first round of rolled opamps (LM6172/THS4032) was in between the Pico and Predator in rank, but closer to the Predator in soundstage - what I considered a good compromise. The whole reason the Pico fell behind the others despite it's audibly superior DAC was the lack of fullness in the lower mids and the way a hard strike on the piano keys would bite my ears. Both of those problems were not audible when using it as a DAC/pre-amp instead of driving headphones - but when I listen with headphones now, those issues have also improved over the months since my initial review (the same ones as back in March).
However, the old D2 Viper top-pick opamp combo had a problem with sucking down the battery in 7 hours, and with being too forward with many of my IEM, allowing the Pico to pass it up with IEM. So I made changes and currently the D2 Viper has the LM4562/LM6172 in it, which is more clear and open and spacious (plus battery life climbed from 7 hours to 17). I would say it is now closer to the detail and space and ambience of the Pico, and I would put the D3 in that category as well. This is good, because they are also rich and not thin sounding in the mids. Seriously, the Predator, Pico and D3 are just so close that I might be ready to be put out to pasture and give up doing these reviews - but I still put the Predator just slightly ahead in how it conveys the emotion of the music in it's tone, although I like the soundstage and space of the Pico a little more.
So, even if the 2MOVE were here today I suspect that I would rank the Predator first, followed closely by a tie for second with Pico, D2 Viper (LM4562/LM6172), and Micro Stack, and I'd have the 2MOVE as a close 3rd. I suspect that all along I should have placed the 2MOVE there because otherwise I would have bought one by now (my 2MOVE loan was way back in April). That leaves me in a quandary as to where to put the D3 Python because while I like it very much, the RF problem makes it difficult for me to place it higher ranked than those in 1st - 3rd place above. And it can't tie with the Pico because the Pico also now has a very slight advantage of smoother upper mids with the RS-1, and slightly more ambient cues and micro-detail in complex passages.
At this point, while sounding closer to my second place picks when I can find a quiet spot in my house, I have to say it is tied with 2MOVE in 3rd. Although I'd rather listen to D3 than 2MOVE at this stage of the game, the RF interference wont let me rank it higher. I recognize that the RF is due to my particular location, and it may not affect anyone else out there like it has for me (will find out tomorrow). Such are the hazards of putting together a subjective review like this, when based on their technical merits either none of them are losers and personal preferences can change, or where personal preferences makes one decide to ignore technical faults. It was like Goldilocks saying this bed is too hard, and this one is too soft, but this one is just right. Who am I to say what you "sleep number" should be. I do think I need to be approaching any reviews in the future with a more objective eye (or should I say, ear), as I feel I am losing some of that here.
Nevertheless, I am now considering parting with the D2 Viper because the D3 sounds just as good, has 7x more battery life, and it also sounds great as a DAC-only when I feed a full size amp (without needing any batteries). While the D2 Viper can be made to sound similar to a Predator with the right opamps, and closer to the Pico with others, the D3 Python splits the difference well enough that it doesn't matter. Despite the nice DAC in the D3, I'm pretty sure right now that the D3 will spend most of it's time replacing the D2 viper as my "iMod amp". The Predator remains paired with my 3G Nano as the combo is pretty wicked sounding for such a small package. And the Pico will continue to be used the most with my Macbook and either powering headphones or used as a DAC/preamp feeding a desktop amp. If it wasn't for the nasty RF problem in my neighborhood caused by the radio towers right behind my house, I'd maybe use the D3 for the macbook instead because of the improved battery life.
UPDATE 11/6/08: Cannot fit the ranking in the first post after the D3 review without exceeding the 100,000 character limit. See 01/04/09 or newer rankings in the second post.
UPDATE 12/15/08 - CANNOT FIT MY FULL NUFORCE ICON REVIEW BELOW INTO THE FIRST POST, EXCEEDING 100000 CHARACTER LIMIT - SEE SECOND POST FOR FULL BODY OF NUFORCE REVIEW:
HEADPHONES USED: Westone 3, Klipsch Image X10, Denon C700, Nuforce NE-7M, ATH-ESW10JPN, APS V3 cabled HD600, APS V3 cabled RS-1, APS V3 cabled markl Woodied Denon D2000, and APS V3 cabled Edition.
MUSIC USED: Michael Knowles "Bink Audio Test CD", Nils Lofgren "Acoustic Live", Arne Domnerus "Antiphone Blues" and "Jazz at the Pawnshop", Infected Mushroom "B.P. Empire", Tord Gustavsen Trio "Being There", Pat Metheny "Day Trip", Tsuyoshi Yamamoto "Autumn in Seattle" and "Smooth Jazz Festival", B.B. King and Eric Clapton "Riding With the King", Shelby Lynn "Just a Little Lovin'", Nora Jones "Not Too Late", Arvo Part "Tabula Rasa", Jack Johnson "Sleep Through the Static" and "In Between Dreams", Elaine Elias "Something for You", Gary Karr "Super Double-bass", Guinea Pig "Kool Cats", Christopher Hogwood "Handel Messiah", Pink Floyd "DSOT", The Beatles "Love", Beck "Sea Change", Diana Krall "Girl in the Other Room", Coldplay "Viva La Vida", and Skillet "Comatose".
The Nuforce Icon Mobile is a $99 entry level portable USB DAC/Amp, which has more of a flat form factor that is amenable to being stacked under an iPod without adding too much size to the overall package. It is about the same width and depth as the iBasso D2 Boa, but almost half as tall/thick, so you can almost stack two Icon Mobile on top of each other to achieve the thickness of one D2 Boa. When plugged into the Macbook's USB port the DAC shows up as a "C-Media USB Headphone Set". The Nuforce has some unique features including two headphone out jacks which switch on the power when a headphone plug is inserted, with the jack closer the center being a special jack that works with 4-conductor headsets with stereo headphones and a built-in microphone, like the Nuforce NE-7M iPhone IEM (or other iPhone IEM). This allows the NE-7M to be used as a headset with telephony applications, instant messaging and Skype, and probably for gaming as well. I have not been able to test this telephony feature, but the mic did show up in my Mac's Audio MIDI setup application as the left channel only microphone. The analog input is on the same end of the amp as the two outputs (we'll call it the top end), and all three jacks are slightly recessed by about 0.5 mm along one edge of the amp...
Post is too large to edit... SEE POST #2 FOR THE FULL REVIEW and RANKING - http://www.head-fi.org/forums/3947073-post2.html
UPDATE 01/04/09 - XM5 USB DAC Amp by Practical Devices Corporation CANNOT FIT REVIEW INTO POST #1, FULL REVIEW IS IN POST #2:
I used my usual playlist of lossless songs and typical rotation of headphones with the XM5, and I really like the XM5 - the quality of sound it puts out deserves the $245-$325 that it sells for (depending on options like optional BUF634, or AD8397 kit, or Li rechargable vs Alkaline). Based on the sound, I assume this dual mono amp has to be a major upgrade from the XM4, not just an evolution. It comes stock with a pair of OPA134 opamps, which are single channel opamps, and it has a pair of buffer sockets for improved current output by using optional BUF634 chips, or another opamp like AD8397 in the buffers. It come standard with using a 9v alkaline battery (50 hours), and a charging circuit for rechargables is optional (40 hours).
SEE POST #2 FOR THE FULL REVIEW and MOST RECENT RANKING - http://www.head-fi.org/forums/3947073-post2.html
RANKING: I HATE THE RANKING BECAUSE NOW I HAVE TOO MANY 3RD PLACE TIES, ALTHOUGH FOR DIFFERENT REASONS, and I would not wish to part with any of the amps in 3rd or higher because they all have an area where they excel. (except D2 Viper which could sound like a Predator or a Pico but was redundant with poor battery life and was sold). Anything in 4th and below is expendable, even if very good sounding. I previously moved the 2MOVE to 4th because I couldn't remember how good it sounded, having not listened to one in months. Now I have a 3MOVE which sounds like a 2MOVE with an upgraded case, and I can fix my ranking. See additional comments included if you haven't read the entire review:
1. RSA Predator (good bass and soundstage, more body, organic, full. Seems to do well with all my headphones, and not bad with any. Gobs of power with RS-1, D2000 and Edition 9 but Could use a little more power with HD600 - very underpowered for AKG K240M 600 ohm. DAC is not as good as the Pico, but the sound of the amp makes up for it)
2. D2 Viper with rolled opamps (with LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. With my IEM I found it sounded better with the LM6172 and THS4032 swapped. This second opamp configuration was good with all my IEM, and not bad with my full size phones, except the RS-1 seem a bit bright and the Proline 2500 lacked fullness in the mids. With LTC6241HV/LMH6622 sounds like 98% of the Predator with only 7 hour battery life. Later I discovered the LM4562 main/LM6172 ground, and this works very well for full size phones and IEM - very open and spacious and detailed, sounding closer to the Pico without losing any warmth or rich tone. And battery life was bumped from 7 hours to 17 hours!)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1. It really seems to shine with my re-cabled Denon D2000, Klipsch Image, Freq Show customs, but doesn't sound bad with anything but my Proline 2500). Over the past few months the Pico has really been growing on me, and it no longer seems to lack warmth with my RS-1 or other headphones (especially since I sold the PL2500). The DAC's space and ambience and soundstage still stand out as slightly superior, as before, and it seems to do well with most IEM but not all)
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off).
3. 2MOVE/3MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy, sounds as good as Pico but it's a different sound, sometimes too forward. NO iPhone Buzz. Auditory memory fades as I hadn't listened to the 2MOVE since April, so I bought a B-stock 3MOVE and found I do still enjoy it very much. Since I am liking open and spacious sound a little more now, the Pico moved up to tie the 3MOVE rather than move the 3MOVE down. I did add listening to the Westone 3 with this amp and they are fantastic together. 3MOVE is a better match for the D2000 and RS-1 than XM5, while I liked the XM5 more with HD600, Edition 9 and ESW10, even though 3MOVE had more power for HD600)
3. Practical Devices XM5 (amp section better than D3 and rivals higher ranked amps, but DAC not as good as the D3 - so it evens out. Gets along better with more of my headphones than D3 and with all of my IEM, and I am having no iPhone buzzing with it so far. A chameleon - many times it sounds like my Predator, and other times it sounds more like the 3MOVE, and the amp section really shines with iMod or an external DAC)
4. D3 Python (very sensitive to RF interference from Cheyenne Mountain and NORAD. The sound is very close to the 3rd place amps, and I like it very much, being only slightly less smooth in the upper mids with Grado than Pico, and very slightly less micro-detail in ambient cues and complex passages, dropped in rank because of RFI problems)
5. Nuforce Icon Mobile (More forward than D2 Boa and closer to Vivid V1 and 2MOVE in that regard, has good synergy with Westone 3, Klipsch X10, Nuforce NE-7M, Denon C700, ATH-ESW10, D2000, and Edition 9 - sounded nice with HD600 but a bit under powered with HD600 and not worth trying with 600 ohm AKG K240M. With RS-1 occasionally had a similar upper mids coloration like Vivid V1 and sometimes needed to switch to the flats to enjoy them more, so not first choice for Grado but would not avoid the amp because one owns Grados, good midrange detail but not as full and rich sounding as the top tier amps above except with D2000, Edition 9 and Westone 3 which bring that to the table on their own)
5. D2 Boa (Sonic signature slightly warmer than the Pico, and between the D2 Viper with LM6172 in the main amp (warmer) vs THS4032 in the main amp and LM6172 in the ground (cooler). Timbre and tone was good, and lower mids were slightly forward and rich, and highs had slightly less extension than the D2 Viper or Pico and Predator (in that order). The sense of space with live performances was superior with the D2 Viper, Pico and Predator (in that order), and LESS with the Boa at 300 hours of burn-in. However, the Boa did open up and gain more air and ambience on the level of the other top ranked amps by 575 hours of burn-in. Listening to Diana Krall "Girl in the Other Room" (Temptation and other songs) seemed to indicate more of a low mids hump than the other amps, which also caused problems with Pianos and realism on that CD. The problems reproducing this particular CD remained after 575 hours of burn-in, however with other CD's like Jazz at the Pawnshop, Handel Messiah and Tsuyoshi Yamamoto the D2 Boa demonstrated improved transparency and realism with the extra burn-in. And with other music it seems the bass extension is slightly less than the others in the top ranks, but by 575 hours of burn-in (with my RS-1) the 16Hz audio tones on Binks Audio Test CD were clearly audible, and the volume of the 20Hz tone caught me by surprise, while 25Hz was a little disorienting! With over 800 hours the lower mids hump is less noticeable with female and male vocals now, but the middle mids and upper mids now seem to be more withdrawn instead.
6. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241. The D2 Boa moved up a little with more burn-in, but it wasn't quite good enough to rise up to a 3rd place tie. So the modded D1 and everything else had to move down a slot. The D1 via USB isn't as good as via optical, which is why it is not tied with the D2 Boa after the Boa improved with extended burn-in. With optical input would beat the Boa easily.
7. Vivid Technology V1 (very good synergy with HD600 and AKG K240M 600 ohm, nice and fun with Edition 9 and Klipsch Image X10, acceptable with RS-1 IF switching to flats but bowls are not recommended, unacceptable with my Freq Show but not the amp's fault. DAC with slightly more micro-detal than stock D1 via USB or Headstage Lyrix, slightly less than either D2 Viper/Boa or the other amps. The most forward of all the amps. Can be near 3rd place with HD600 and Edition 9 or 2nd with K240M, but 8th place with Grado RS-1 and bowls and last with Freq Show)
8. D2 stock - tied (thin in the middle, neutral with good bass - it was sound signature and power but not level of detail that held it back with the stock opamps.) Sounds good with Freq Show and most of my IEM, fairly good with HD600 and Edition 9 but lacks power, not bad with RS-1 but can't properly drive AKG K240M 600 ohm. Sounds better with re-cabled modded ATH-AD900 than the Boa or V1.
8. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great with analog input.)
9. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 7th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 8th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
I should note that any of these amps are very pleasing sounding.
Feb 22, 2009 UPDATE - iBasso D10 REVIEW AND REVISED RANKING:
This 1st post is at the limit - see review in post #2 below: UPDATED 01/04 REVIEW 12 USB DAC amps - Predator, Pico, 2/3MOVE, D3 D2 Viper/Boa D1, Lyrix, MicroAmp, Vivid V1, Nuforce, XM5 - Head-Fi: Covering Headphones, Earphones and Portable Audio
Jan 29, 2010 UPDATE - iBasso D4 IMPRESSIONS, PENDING FULL REVIEW. Will try to post a more complete review in post #2 as soon as I can. At this point, I put the D4 in my top spot for features and sound combined, although if battery life along with a high end DAC is important to you then the D10 still makes more sense.:
FIRST IMPRESSIONS - http://www.head-fi.org/forums/6146137-post932.html and http://www.head-fi.org/forums/6147003-post934.html
D4 vs D10 and others, with opamp rolling - http://www.head-fi.org/forums/6264269-post962.html
More Comparisons - http://www.head-fi.org/forums/6274204-post972.html
In the final ranking, the 8 amps in 1st -5th place are close enough to be a tie, and my ranking is based on personal preference and features, not only sound.
3/14/08 - Initial Review Four USB DAC Amps: Tonight I compared SEVERAL USB DAC amps that I own. SEE UPDATES BELOW FOR ADDITIONAL AMPS - including the 2MOVE and HR Micro Stack, the D2 Boa, the Vivid Technology V1, iBasso D3 Python, Nuforce Icon Mobile, Practical Devices XM5, iBasso D10 and D4 in Post #2.
(1) RSA Predator #24 with 1100+ hours, reviewed by Skylab last month
(2) Pico #11 formerly owned by Asr and broken in
(3) iBasso D2 with 183 hours
(4) Headstage Lyrix with 400+ hours
PHONES: I reviewed them using my ALO modded Vampire wire HFI-780's which have 450 hours on them - these have excellent frequency response and transparency, and are ruthless in exposing a bad source or amp, and fantastic at exploiting a good source or amp.
SOURCE: Listening was via USB on a Macbook with Apple lossless files as the source. At any one time, two of the four amps were connected via USB, and I would switch ports via the sound control panel, then quickly swap the headphone plug out. All amps were on low gain - and I tried to match volumes by ear - the Lyrix and D2 volume knobs were at 1:30 o'clock, the Pico was at 1 o'clock, and the Predator was at 3:30 (but it is the only one with three gain levels).
MUSIC: Apple lossless files - Tsuyoshi Yamamoto "Autumn in Seattle", FIM "This is K2 HD CD" and "Jazz at the Pawnshop", Diana Krall "Girl in the Other Room" Dual-Disc.
FINDINGS: They are all very good, but have differences. You would not be dissatisfied with any of them, but you can tell which are the $500 amps and which are the $200 amps. If the money is there, I would give it up for the more expensive ones; not because of the cost, but because of the open windows into the music they provide.
FIRST: The Predator is still my current favorite for sounding like a full size amp (so far), but I have more sources and phones to try all the amps with. The bass is deep without being boomy, and the mids and highs are warm and smooth, with good transparency. It does have a just a little bit less treble extension than the Pico, which is fine with the ALO modded HFI780's and most headphones. I have tried high gain before, and it drives HD600 with no strain at all.
The Predator strikes me as being different, in the same way that a wood Grado has a different timbre than a plastic or metal Grado - with the Predator being wood with warm natural timbre and the Pico being the "not-wood" or more neutral one.
SECOND: As a very close second is the Pico S/N #11 which was the one used in Asr's loaner tests (many hours on it) and it just arrived today. It was nice, but with maybe/possibly a little tipped up extreme ends of the bass and treble, adding a slight brightness but not sibilance. Otherwise it is pretty neutral and powerful, but slightly colder than the Predator. Both are equally detailed, however the PICO soundstage is a tad larger or slightly more open sounding.
I would bet that some of my headphones might appreciate the neutrality a little more, and I will explore that. However, I can see why many people are using these as a volume controlled DAC, because it doesn't seem to have much of a flavor of it's own. I will try it as a DAC to my tube amplifier, and report back later.
THIRD: [SEE UPDATE BELOW, AFTER BURN-IN AND NEW OPAMPS D2 VIPER MOVED TO SECOND] In 3rd is the iBasso D2. It has a very similar sound signature and frequency response as the Pico - but maybe tiny bit boomy in the bass, a tiny bit less volume in the mids and a little bit brighter in the treble (more U-shaped). It was not quite as smooth in the treble or as transparent as the PICO (D2 has 183 hours on it).
The bass has gone up and down over the past 48 hours, and for a while it was too much, but it is leveling out now but still slightly more than needed. I expect it to continue to refine itself with more hours under the belt.
FOURTH: Then there is the Headstage Lyrix Total Pro USB. Fourth place doesn't mean last place, since it is still a very good amp. It sounds very similar to the D2 in frequency response, but with a little less transparency than the D2. Switching between the Pico on one USB port and Lyrix on the other USB, then the decrease in transparency even more apparent. It is still a very detailed and clean amp, but with less air around the instruments vs the other amps when driven by it's limited PCM2704 DAC. The bass was not boomy unless the bass boost was switched on, but it was slightly less than the D2 when off. In no way was the bass inadequate, rather the D2 is just a smidge much (is that a word?).
This amp has loads of features, like 9v re-chargable or Alkaline compatable, with charge circuit off-switch, bass boost, crossfeed. BUT, it is also twice as big as the other three (sorry no pic, it got left out in my wife's car when she took my daughter to girl scouts). It has been relegated to being the desktop amp for the iMac in our kitchen because it is still too good to sell.
WHAT'S MISSING: You may ask, where is the iBasso D1? Well... Blutarsky had sold off all his portable amps, and I loaned him my D1 two weeks ago to try with his ALO vampire wire 780's. I had recently rolled the opamps to AD743/LMH6643/LTC6241 which synergized very well with them. Somehow, last weekend I left his house owning all of his headphones except his Darths and my HP-1000 and D1, which stayed with him. From memory I am going to say it sounded similar to the PICO, when I was using it with the Mac Audio Midi set in 24bit/48Khz mode via optical out. Not quite as warm as a Predator, but powerful clear and neutral like the PICO.
PLANNED FOR THE FUTURE: I plan to try all 4 amps with several headphones this weekend, and will also try their analog inputs with my iMod and ALOaudio Jumbo Cryo Silver X LOD. Cheers, and happy listening!
...and sorry about your wallet!
UPDATE #1: I should mention that the RSA Predator takes a huge amount of time to burn-in. It wasn't so great sounding right out of the box, I mean it was good but not spectacular. By 300 hours it had gradually changed till it sounded nothing like it did fresh out of the box, and a veil was starting to lift. By 600 hours it was a whole new amp again, with real meat to the bass - and again this was via gradual slow changes (and not bouncing around like the D2 did). By 1,000 hours it seemed to me to be fully matured, with no changes between 1,000 and 1,100 hours. At that point, the Predator was shipped off to Skylab for his review in February.
UPDATE #2, 3/15/08 1:00AM: The D1 as I mentioned most recently had the AD743/LMH6643/LTC6241HV opamps in it. Previously it was warmer with more bass, and closer to the Predator, when it had the AD797/AD8397/AD6241HV in the LR/BUFFER/DAC opamps in place. That was before I rolled the opamps for the HFI-780. I suspect I'll be able to similarly tune the D2 and Lyrix which have socket opamps as well. I am not in a rush to do so yet.
UPDATE #3, 3/20/08 11:45PM - D2 VIPER STOCK MAKES POSITIVE GAINS AFTER 300 HOURS.
I have 311 hours on the D2, and I am now using my Woodied HF-1 with APS V3 cable at the moment, and all amps were driven by the USB DAC as before. So, I am revisiting it as promised with an extra 125 hours or so on it. I listened a lot on Monday and Tuesday with my Grados and Edition 9, and then took a 48 hour break while it burned in the final bit to reach 310 hours.
While the D2 initially had a very similar sound signature to the Pico, my 183 hour impression of the D2 was that the bass was a bit boomy and uncontrolled, and it seemed a little brighter than the Pico. Now the bass has indeed tightened up since the last time I listened on the 18th when I compared the amps with more headphones. Not only is the D2 bass now less boomy and more controlled, but the high's are a little smoother too (but maybe still a tad brighter).
With the extra hours on it, the D2 is clearly closer to the Pico than it is the Lyrix now, as the Lyrix DAC is seeming to hold it back now. But, there is that final bit of transparency and smoothness that the Pico holds over D2 still. I would say the top three amps are within a few percentage points of each other, when listening with the HF-1 APS re-cabled woodies. There is just something about warm full bodied sound of the Predator that keeps me coming back for more.
So, I give the Predator a 10/10. I'll give the Pico a 9.7/10 for opening the soundstage a bit and crisp detail, but with a cooler more analytical sound. The D2 has moved up from a 9.0 to a 9.4/10 for the D2 now, while still missing some of the warmth of the Predator and the final bit of transparency of the Pico. I have to give the Lyrix a 8.8/10 now. To me anything above an 8/10 is great but might not be a keeper if I have more than one amp sitting above 9/10.
I would put the D1 (with the newest round of opamps) right up there with the D2 now (sound is quite close), except that I got it back after 2 weeks with a channel imbalance, so I have to open it up and swap opamps and determine if the problem is my fault, or I have to contact iBasso. The right channel is louder using the DAC by a good 3db or more, but with the analog input the L/R channels are balanced. It currently has the AD743x2 in it for main, LMH6643 buffers, and LTC6241HV in the DAC.
UPDATE #4, 3/26/08 2:00AM - 2MOVE and MODIFIED D2 WITH NEW OPAMPS
I just spent the last 9-10 hours with all the amps, and a well burned in 2MOVE from Skylab. I first listened them all with the ALO modded HFI-780, but my current sinus infection must be boosting the vampire wire 780's bass a bit too much vs 7-10 days ago. So, I switched to my APS re-cabled RS-1 for more detail and layering, and more balanced bass, and listened to everything again. Having just gotten the APS re-cabled RS-1 and also re-cabled my Edition 9, it is an eye opener into hearing that the ALO modded HFI-780 are darker and bassier and less open at quiet volumes than I remember with the first part of the review (they do open up at higher volumes but louder make my sinus headache worse). Right now I am preferring the RS-1 and Edition 9 vs my 780's with 666 hours on them (don't laugh, that's how many hours they have
All Amps were reviewed as before, using only their USB DAC as source, via Macbook. The D2 was also tested with new opamps, with a LM6172 replacing the LT1364, and a THS4032 replacing the NE5532.
I used the same music as in the first test, but had to add a few more items: "Handel Messiah" conductor Christopher Hogwood, William Orbit "The Best of Strange Cargo", James Asher "Shaman Drums", Guinea Pig "Cool Cats", Jack Johnson. I also threw in various pop artists from my kid's music in 128kbps to test with poor sources.
The 2MOVE sounded closer to the Predator than the PICO, but with a little more treble extension and what I would call a slight midbass hump that I did not hear in the Predator other amps. The 2MOVE was what I would call warm and mellow - but not dark as it had a little bit more treble up top, in between the Predqtor and PICO (like the D2). The Predator seems to have a little better bass presence, especially helpful with the RS-1 which I feel are usually a little bass shy with bowls. The Predator's high end was also more suited to the RS-1 and HFI-780's which already have a strong treble presence. Bass and treble were not overpowering with any of the amps with the RS-1.
The 2MOVE was more forward and up front than the Predator or Pico, which didn't help the soundstage with Handel's Messiah when listening via the RS-1. The 2MOVE still has excellent ambience and detail of the large venue, but you are definitely closer to the choir. The Predator's bigger soundstage was itself beaten by the Pico by a small margin, which produced a more 3D Cathedral space. With one small studio recording (Tsuyoshi Yamamoto on FIM XRCD), I can almost hear the drums and cymbals echo off the walls with the 2MOVE, but that coloration does not appear to be there with any of the other amps.
The 2MOVE with piano and saxophone was sweet and seductive, like the Predator, where you could hear the warmth and the reedyness both at the same time. Where the 2MOVE also excelled was in acoustic music like Jack Johnson, like in "Badfish" on Look at the Love We Found, or "Times Like These" from the "On and On" album.
ALL the amps did electronic music well, like William Orbit, Chris Spheeris, James Asher. And ALL the amps are particularly ruthless with poor quality Mp3, revealing the poor dynamics and compression artifacts. With ALL of the amps I heard a grating quality with my kids' 128kbps pop/hip hop like Plain White T's. The Fray, Cartel, Avril Lavigne, Boys like Girls, Chris Brown, Wyclef Jean, Rihanna, Fergie, etc, which rubbed me the wrong way.
Back to the good stuff. What surprised me was listening to Diana Krall - the PICO just sounds more natural and transparent with songs from "Girl in the Other Room". This album gets included every time I do a review because it is mastered with some sibilance or harsh highs still remaining, so it makes a good test album to see how the amps or headphones handle it. While the Pico handles this the best, just above the Predator, I thought the 2MOVE was the most irritating of the amps with this partitcular album, and this hurt it's score. However, with the low-bitrate kid's music above, it was no more irritating than any of the other amps.
Now we get to the D2 with rolled opamps, using the LM6172 and THS4032 opamps, which would be about $25-30. The opamp change definitely changes the character if the amp, and it is less "Pico-Like" and more 2MOVE-like, except that it handles the one Diana Krall CD a little better/smoother, and it is slightly less forward, and the midbass hump is less. So, I guess that makes it more predator-like then?
Having picked out the areas where one amp excels over the others, or falls behind the others, it makes it even harder to rank the top 4 amps. The Predator, 2MOVE and modified D2 sound the closest to each other's sound signature or flavor. While the Pico and stock D2 sound the closest to each other's sound signature. A similar sound signature is a "reminds me of" NOT a "sounds just like". That puts the amps in 2 camps, yet makes all the rankings fall between a 9.4/10 and a 10/10, and in my opinion too close to call based on sound alone.
The D2 with rolled opamps I feel is a little better than the 2MOVE, while the 2MOVE is better than the stock D2. So, my initial ranking has a tie for 3rd, and a tie for 4th...
1. RSA Predator (good bass and soundstage, more body, organic, full)
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1)
4. D1 with rolled opamps (AD743 main/LMH6643 buffer/LTC6241HV DAC - powerful, punchy, energetic, alive)
4. D2 stock (thin in the middle, neutral with good bass,)
5. Lyrix (good frequency balance, lacking details and air vs the others)
6. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant)
Quote:
| Originally Posted by Raw notes jotted down while listening: Predator - ALO 780 = less treble extension, best bass Predator - RS-1 Handel mellow, good soundstage Yamamoto piano good Diana Krall voice smoother than 2move Jazz at Pawn - smooth, natural live William Orbit - punchy 2MOVE - ALO 780 like Predator with more treble, mid bass hump 2MOVE RS-1 Handel mellow forward Yamamoto good piano Diana Krall good bass, voice grating Jazz at Pawn sax sweet William Orbit - punchy PICO - ALO 780 clean bass, transparent PICO RS-1 Handel more 3D soundstage, clear airy Yamamoto bright piano, wrong Diana Krall best voice Jazz at Pawn - saxaphone thin William Orbit - punchy D2 modded - ALO 780 like MOVE but not as bright & less midbass hump D2 modded RS-1 Handel open slt more highs, violins closer than singer? Yamamoto less bright vs pico Diana Krall not bad at all Jazz at Pawn - sax sweet/magical William Orbit - punchy |
UPDATE - 05/06/08 11:50PM: 7 USB DAC AMPS - ADDED HR Micro Stack Portable
(1) The Headroom Micro DAC and Micro AMP, 2006 version, AKA HR Micro Stack portable:
The HR Micro Stack came into my possession the first week of March, and I initially considered including it in this review, but I wanted to focus on the newer smaller combination portable USB DAC/amps first. Headroom now has a 2007 Micro portable DAC/Amp for $598; but the DAC chip is different, and they admit that the new Analog Devices DAC is a slight downgrade from the 2006 portable with Cirrus Logic CS4398 chip (they claim the 2007 desktop Micros with the CS4398 are still as good or better, but without 9v battery power).
This is a fairly large (for portable) two-piece set, with a separate DAC and matching Amp section. When strapped together with the optional Micro-Strap they act as one large unit and take up a 3W"x4D"x3H" piece of desktop. That is bigger than the iBasso D1, so it certainly wont fit in your pocket (not even a coat pocket), and is really what I would call transportable. Even worse, this means you get two medium-to-large sized power bricks, with proprietary connectors on the amp and DAC side, and no internal charging circuit. You have to buy a separate battery charger, and the one I have can only do two 9v at a time. Yikes. I haven't tested battery life, but I have read tales of the amp chewing through a pair of 9v re-chargables in 8 hours, and the DAC lasting maybe twice that. I will try to test out the 9.6v re-chargables that HeadRoom sells soon. See a recent previous post for battery life of the other amps reviewed.
I now have about 400 hours on the Micro Stack, about half from just regular use of music and not running it 24/7 after the first 180 hours. And I just feel that I need to add this to my review, and to let people know what to expect if they buy a used one down the line. There are a fair number of these out there, and they don't go up for sale used very often, and there is a good reason for that - they sound good.
I did my comparison against the Pico, and planned to pull out one of the other amps should the Headroom fall above or below the Pico, but I made a lucky guess and found them to be fairly equivalent. I used all the same program material, and listened with my RS-1 and D2000 (my HFI-780 were with mrarroyo at the time).
The HR Micro Stack via USB reproduces vocals and real acoustic instruments well, with no colorations and drop outs. Diana Krall was smooth, without sibilance, but female vocals and saxophones were just ever-so-slightly cooler than I like. Pianos were sharp with quick attack and smooth decay, and were not piercing. The sound does not seem boosted or sucked out in any areas.
There is a nice sense of ambience and space around the instruments, without making the venue sound cavernous (or microscopic). Rather, it is just right. With classical music I dare say it can recreate the large hall ambience slightly better than the Predator, and it reproduced the Cathedral-sized venue for Handel's Messiah as well as the Pico did. With smaller nightclub venues, and studio recordings, the ambience and dynamic range was good as well. I did not hear the sound of the instruments or the echos disappear too fast like with the Lyrix USB DAC (or Travagans Green).
Switching to optical digital, I can hear slightly better air and ambience with Headroom's optical input and my Macbook. I should note that while optical is a little more transparent, the USB performance is still pretty darn close to optical. Even when playing native 24/96 program material from Linnrecords.com Hi-res downloads, and setting the Macbook optical output to 24/96, the differences in sound between the HR optical input and the USB input of both the HR and Pico were fairly small (maybe a 5% improvement).
So, what about all my previous postings about the Micro Stack being a warmer and more musical setup, if it really sounds like a Pico? Well, I use the Micro Stack with crossfeed switched on 90% of the time. And the HR Micro Amp's sound warms up when you hit the crossfeed, even more than the Lyrix does with crossfeed. Whether it is better that way depends on the listener, the source, the program material and the headphones. With crossfeed off, there is very little difference in sound between the Headroom Micro Stack via USB and the Pico via USB. However, the HR Micro Stack is just a bit richer in the mids than the Pico when crossfeed is on, but also sounds slightly rolled off in the highs with crossfeed (more rolled off than the Predator). To my ears, the Lyrix and HeadFive tend to lose a little of their air and ambience when crossfeed is on; but the HR with crossfeed still seems to retain decent space and ambience, despite the slight rolled off highs.
Basically, via USB the $598 HR Micro Stack's performance and sound signature were similar enough to the $499 Pico to call it a draw. But, the optical S/PDIF digital input adds a small additional layer of ambience and transparency to the sound. The trade-offs for the gains with optical are bigger size, inconvenience of recharging batteries externally, out of production and higher cost. This is great for my iRiver and Sony portable CD Player with optical at the bedside. But if you are putting together a computer only rig and just wont use the S/PDIF inputs, then there are better choices reviewed here that will give you great sound in a smaller and more convenient package. If you need the crossfeed on a computer-only rig, get the 2MOVE - although it's affect was more subtle than Headroom or Headfive, it did not seem to affect the sound signature much, or cause a roll-off in the highs.
(2) Some notes about the Lyrix Pro USB Total, Lyrix Pro (and it's little brother the Caffeine Pro):
I've had several inquiries about the Lyrix, whether it is the DAC or the Amp that holds it back. I believe it is the DAC that holds it back, even though the DAC sounds better than headphone out of a 5.5G iPod or Macbook (which not surprisingly sound similar to each other and could use improving). It also confirmed for me how important burn-in is with these small amps, as I got to compare a new vs 500 hours side-by-side.
Let me preface by saying the Lyrix Total Pro needed about 70 hours burn-in to open up and smooth out, then about 200 hours burn-in to get to 95% of it's potential, and after 300 hours there were few if any changes to the refined smooth accurate sound they produce. Interestingly, I couldn't hear much change when flipping on the crossfeed when new out of the box, or even in the first 70 hours. By the time I had 200 hours on it, the effect was more audible. Other people have reported the same findings with the Lyrix crossfeed vs burn-in.
When I got an extra Lyrix Pro for my son a couple of weeks ago, my Caffeine Pro (basically the same amp) and Lyrix Pro USB Total had over 500 hours each. In comparing the new one I could hear the constriction in soundstage, less warmth in the lower mids, and a slight coarseness in the highs. Now, at 150+ hours it is pretty hard to tell the differences between Lyrix Pro and the Caffeine Pro, while there is still a slightly more refined quality to the sound of the Lyrix Total. The warmth in the lower mids doesn't seem to develop in the Lyrix till after 150+ hours of burn-in, and while it is still a little behind that of the Predator, Pico, 2MOVE or Headroom, the amp section by itself is close to the HeadSix and still ahead of the stock iBasso D1 or D2.
(3) Because of all the questions about whether the main differences in my review are from the DAC or the Amp section, after I got my D1 back from iBasso I briefly listened to most of them with analog input from an iMod, instead of via USB DAC. (except the 2MOVE which I don't have)
People keep forgetting how close they are already, as I've said many times, and I love them all. There isn't a big difference between an amp rated 9.4/10 and a 10/10 (which is where most of them sit). So, as expected the sound quality of most of the amps via analog input is just as close as when using their internal DAC (the exception is the Lyrix amp-only is now better than a stock D1 or D2).
Although their basic sound signatures remain mostly unchanged, using the same source (the iMod's DAC) slightly lessens the differences into just their own essence or flavor, what we call sound signature. The differences in sound quality would still be in the single digit percentage points, and subject to personal preferences (except the stock D1 with analog input is not terribly impressive - it really needs the DAC or new opamps to wow you).
Newest Ranking 05/06/08:
1. RSA Predator (good bass and soundstage, more body, organic, full)
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1)
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off)
4. D1 with rolled opamps (AD743 main/LMH6643 buffer/LTC6241HV DAC - powerful, punchy, energetic, alive)
4. D2 stock (thin in the middle, neutral with good bass,)
5. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great)
6. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant)
Newest Ranking 05/12/08:
Today I had to change opamps in the D1 in order to ship to someone, and I needed to rob 4 screws from the D2 temporarily (a long story), so while the D2 was open I returned the D2 back to stock just for a quick listen. So, I compared the D1 with AD797 main, LMH6643 buffers, and LT6234 in the DAC vs the stock D2 with LT1364 + NE5532.
The D1 with the above opamps is clearly better via USB than the stock D2, so I changed the rank from the stock D2 tied with the modded D1 for 4th, and moved the stock D2 to 5th place. The D1 with the above opamps is so good that it almost ties the Pico and HR Micro Stack for 3rd, but not quite (however via optical it might move up).
1. RSA Predator (good bass and soundstage, more body, organic, full)
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. 7/5/08: With my IEM I found it sounded best with the LM6172 and THS4032 swapped and the LM6172 in the ground channel. With the LM6172 in ground, the THS4032, AD8397, ISL55002, and LM1364 all sounded good in the main socket, although the LT1364 is slightly rolled off in the highs this way. This second option was good with all my full size except RS-1 seem a bit bright.)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1)
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off)
4. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241)
5. D2 stock (thin in the middle, neutral with good bass,)
6. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great)
7. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 6th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 7th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
Newest Ranking 07/31/08: Added iBasso D2 Boa. Comments below in Red were added 8/11/08.
I received a D2 Boa from iBasso and gave it 300 hours of burn-in like the Viper needed, and then I have used it another 20 hours for music over the past week listening to music. I listened with my Proline 2500, D2000, RS-1, Edition 9, Livewires, Freq Show, Klipsch Image and Sleek SA6. I compared it to most of the amps from before, except I do not have the loaner 2MOVE, or my iBasso D1 or Lyrix Total Pro any more. However, my Lyrix Pro with USB DAC Cable sounds the same as the Lyrix Total Pro, so I can use that for comparison if something is close in rank to it. The Boa was high enough in the ranking that I didn't need to bring out the Lyrix.
The Boa is a pleasant amp to listen to. As far as timbre and tone and frequency balance it is certainly better sounding than the stock D2 Viper to my ears. It does not sound as hollow in the mids as the stock Viper, so the Proline 2500 for example sound better with the Boa than with the Pico or stock Viper.
Listening to the saxophone in Tsuyoshi Yamamoto "Somewhere over the Rainbow" it had the pleasing warm-breathy and reedy-air sound at the same time, just the way I like it with the Predator, modded Viper, and 2MOVE. However, listening to Diana Krall "Temptation" I noticed that the lower mids seemed to be a little over-emphasized in her voice. With many of my headphones, the Boa could be a little too forward in the 250Hz range and could make pianos resonate a little in my ears. Because of this I did not like the Boa with my Freq Show customs or Klipsch Image as much as the other top three amps, but it was still acceptable.
With string bass, the D2 Viper with LM6172 in the main amp produced noticeably more powerful bass with much better impact. However, vs the stock Viper opamps I felt the bass was similar. The treble in the Boa seemed slightly less extended than the Viper, Pico or even Predator. However, at times the highs could seem smoother than with the Predator, which sounded slightly more aggressive when listened to side by side.
The Boa seemed to be lacking some of the transparency found in the the 1st-3rd place amps, as the air and ambience hasn't fully developed yet to what I think it's potential could be (based on what I hear in the Viper). I am hoping that this will get better with more hours, as the other top amps have 500-2000 hours on them. It is fairly transparent, but just not quite to the degree of the others, and this is still the case when fed by my iMod and Vcap dock. However, the Boa did open up and gain more air and ambience, to approach the level of the other top ranked amps by 575 hours of burn-in.
The Boa also seemed to have a slightly smaller soundstage than the other top amps at first. With the D2 Viper opamps swapped to the THS4032 in the main amp, the Viper has the most air and space to the musical venue, followed by the Pico and then the Predator, with the Boa somewhat behind those but catching up to the size of the Predator's soundstage by 575 hours of burn-in. Even with the more forward sounding LM6172 in the Viper main amp section, the size of the soundstage was slightly bigger than the Boa until 575 hours, and similar to the Predator.
Some last thoughts. I briefly tried the Boa with my HD600 and Yamaha HP-1 orthodynamics and wished for a little more power, but it was usable - but with the 600 ohm AKG K240M forget about it. There was no problem driving any of my other headphones. The USB charging feature is a major plus for the Boa, as is the doubled battery life vs my Viper.
I would take the Boa over a stock D1 or D2 Viper or Headstage Lyrix. If it wasn't for the extra power and optical DAC of the Headroom, the Boa might have placed above that too. Lately I have been using the Predator the most with my 3G Nano, the Viper with my iMod and IEMs, the Micro Stack at my bedside, and the Pico with the laptop but feeding it into other amps. Since the soundstage and transparency have developed and matured more over time with more hours on it, the Boa may well get used as much as the Predator, Viper or Pico.
Here is the ranking - see comments included: Comments in Red were added 8/11/08
1. RSA Predator (good bass and soundstage, more body, organic, full. Seems to do well with all my headphones, and not bad with any).
2. D2 with rolled opamps (LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. With my IEM I found it sounded best with the LM6172 and THS4032 swapped. This second opamp configuration was good with all my IEM, and not bad with my full size phones, except the RS-1 seem a bit bright and the Proline 2500 lacked fullness in the mids.)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1. It really seems to shine with my re-cabled Denon D2000, Klipsch Image, Freq Show customs, but doesn't sound bad with anything but my Proline 2500).
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off).
4. D2 Boa (Sonic signature slightly warmer than the Pico, and between the D2 Viper with LM6172 in the main amp (warmer) vs THS4032 in the main amp and LM6172 in the ground (cooler). Timbre and tone was good, and mids were slightly forward and rich, and highs had slightly less extension than the D2 Viper, Pico and Predator (in that order). The sense of space with live performances was superior with the D2 Viper, Pico and Predator (in that order), and LESS with the Boa at 300 hours of burn-in. However, the Boa did open up and gain more air and ambience on the level of the other top ranked amps by 575 hours of burn-in. Listening to Diana Krall "Girl in the Other Room" (Temptation and other songs) seemed to indicate more of a low mids hump than the other amps, which also caused problems with Pianos and realism on that CD. The problems reproducing this particular CD remained after 575 hours of burn-in, however with other CD's like Jazz at the Pawnshop, Handel Messiah and Tsuyoshi Yamamoto the D2 Boa demonstrated improved transparency and realism with the extra burn-in. And with other music it seems the bass extension is slightly less than the others in the top ranks, but by 575 hours of burn-in (with my RS-1) the 16Hz audio tones on Binks Audio Test CD were clearly audible, and the volume of the 20Hz tone caught me by surprise, while 25Hz was a little disorienting!
5. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241. The D2 Boa moved up a little with more burn-in, but it wasn't quite good enough to rise up to a 3rd place tie. So the modded D1 and everything else had to move down a slot. The D1 via USB isn't as good as via optical, which is why it is not tied with the D2 Boa once the Boa improved with extended burn-in.
6. D2 stock (thin in the middle, neutral with good bass - it was sound signature and not level of detail that held it back with the stock opamps.)
7. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great)
8. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 7th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 8th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
Newest Update 09/08/08: Added Vivid Technology V1 - long with pre-burn-in and post burn-in comments.
The Vivid Technology V1 USB DAC portable amp is an AD8397 opamp driven amp, with TL2426 railsplitter for ground, which is similar to the Headstage and Penguinamp choice. The DAC Chip is the PCM2704. The battery is 900mAH 3.6V, but the amplifier always runs off a boosted 5.5V supply. The Lithium Ion battery charger is a smart charger that stops charging when the battery is full. The amp always takes power from the battery in all cases (like the Pico), is trickle charged by the USB port, and can be charged 3x faster with the optional wall wart. I ran the V1 for 15-16 hours on battery via analog input and went to bed with it still running, and when I checked it after 22 hours the battery was dead. I get 15 hours from the stock D2 Viper (7-9 hours with various new opamps), over 20 hours with the Pico, over 24 hours with the Boa (never tried longer) and over 48 hours with the Predator (neck paid attention for longer).
The ABS case is 2.6"(66mm) x 2.6"(66mm) x 1.1"(28mm), so held next to the Predator and eyeballing it, it looks about 1cm deeper and taller, and about 1.5cm wider (still smaller than the Headstage). It fits under the 3G nano well, only sticking out about 4 mm on either side of the Nano when the nano is in a leather case. You can visit vividaudiotech.com - Headphone Amplifiers to read up on the specs and amp, and see pictures.
Here is the claimed power output of the V1 (using 1KHz tone, no THD specified) vs the Firestone Cute Beyond.
600 ohm - 50mW
300 ohm - 100mW
200 ohm - 150mW
100 ohm - 200mW
32 ohm - 780mW
16 ohm - 1.5W
Cute Beyond published power output:
600 ohm - 60mw (AKG K240M = 106 db)
300 ohm - 120mw (HD600 = 118 db)
120 ohm - 300mw (AKG501 = 119 db)
75 ohm - 480mw (AKG 270S = 119 db)
32 ohm - 320mw (Grado SR60/80 = 121 db)
This is an amp that clearly benefits from burn-in, and at 350 hours it will sound much better than it did out of the box. Taken from my notes on 8/23/08, using the MS-1 with the amp right out of the box, I felt the upper mids were just a little strident/prominent. It sounded punchy with good bass, good separation and detail, but soundstage somewhat was somewhat constricted. There was some obvious sibilance with Diana Krall "Girl in the Other Room" and a few other songs. The volume knob was around 11 o'clock for normal listening. Without any burn-in, even my Creative Xmod with 200 hours was smoother and more transparent/natural with bigger soundstage.
With less than 15 minutes on the amp and a 2 hour break, I came back and switched to the RS-1. The cymbals shimmer and hang with nice decay, but there is still sibilance on Diana Krall. The upper mids are still prominent but it is more transparent with the RS-1. With bowls bass should be a little stronger than it is, while flats improve the bass and sibilance but shrink the soundstage. Volume with RS-1 is now around 10 o'clock for normal listening, and I will never listen as loud as it gets at 12 o'clock. Trying some test tomes, out of the box the 20Hz tone is in-audible and missing, 25Hz okay, 31.5Hz strong. I had to EQ out 2 db at 2Khz, and 3 db out at 4Khz and 8Khz to fix the prominent upper mids.
At 40 hours of burn-in using 20 min pink noise alternating with 2 min silence I switched to HD600, which adds about 1 hour to the volume knob and I have it at 11 for normal listening and 1 o'clock for very loud music. The sound was nice and warm but clear, crisp and detailed. The HD600 really sounds better with the V1 than with my earlier tests with RS-1 or MS-1. At 60 hours with HD600 I notice a big jump in bass, almost too much midbass, but at the same time it is a little smoother upper mids too. With that kind of change, I decided to wait until the DAC was burned in at the halfway point thru the 300 hour recommended burn-in before listening again. At 164 hours with the RS-1 again, I was able to reduce the EQ settings in half vs the out of box EQ settings above. I then moved it over to my iRiver to finish burn-in via the analog input as recommended by the manufacturer, who stated the DAC and anolog inputs use different circuits and I should split the 300 hours between them. (note: I have over 2000 hours on Predator, over 1000 on Viper, over 600 hours on Pico Boa and Micro Amp and Lyrix with USB DAC Cable, and 350 on V1 for the review).
By 9/7/08 the V1 has 350 hours (164 on DAC), and I am ready for listening. Since it is not quite up to the level of the Predator, D2 Viper with rolled opamps or Pico, I returned the D2 Viper to the stock opamps for the comparisons. The day before I had run the test tones again with RS-1 to compare to out of the box results, and 20Hz is now clearly audible on the V1 while 25Hz is only slightly rolled off vs out of the box where it was not as good. The Pico and Predator are audible to 16Hz, and have more energy at 20Hz than V1, with D2 Boa slightly behind those. The V1 bass extension is similar to the Boa and superior to the stock D2 Viper which is noticeably rolled off at 20Hz. After testing the bass extension with the RS-1 vs out of the box, I had to take a break for my daughter's 15th birthday and come back the next day to start listening to music, so I burned it in an extra 24 hours.
I started with the HD600 and stock cable and found that the tonal balance and Timbre is nice, with good bass, mids and treble. There is no boosted bass, just flat and extended and almost as strong as the Predator but not quite. Certainly no lack in bass, and not bass light. With Infected Mushroom "Dancing with the Kadafi" the bass is rockin', punchy and hits hard. That was my first WoW! moment with the V1 amp (goosebumps and all when I was at 164 hours), which is why I chose to start with HD600. Switching to string bass, it is not supposed to hit hard and it sounds like it should - crisp and quick and present. So it isn't over-boosting the bass levels but it is bangin' when it is supposed to be.
Mids are rich and warm, and not very peaky or resonating in the ears or head, although there does seem to be a mild low mids "boxy" coloration that is very similar to that of the D2 Boa, especially with close miked female vocals. This makes some female vocals like Shelby Lynn in "Just a little Lovin" or Diana Krall in "Girl in the Other Room" sound slightly artificial or less transparent vs Predator/Pico/D2 Viper/HR MicroAmp. Similar to the D2 Boa, I have a hard time noticing this coloration with acoustic and wind instruments or electronic program material, as it's mostly only an issue with vocals. And, this is not with all vocals - switching to Herbie Hancock "River:The Joni Letters" with Nora Jones singing the first track, her voice seems more natural with both the V1 and D2 Boa, and male vocals like Jack Johnson "Sleep Through the Sttaic sound fine with them too.
Treble has a nice sparkle, shimmer and decay to cymbals, and pianos have a sharp quick attack but do not drill into the head. With HD600 the V1 does not accentuate the sibilance present in the Diana Krall recording above, which is a test album I use for that purpose. I also use the "Girl in the Other Room" to test for lower midrange coloration as Diana Krall is very close mike'd and it is easy to push the lower mids over the top as above (which is exactly what I heard).
The soundstage is similar to the 2MOVE, not too close and not too distant, although it is somewhat more forward than the Predator (making it closer to that of the 2MOVE). It is certainly more forward sounding than the Pico, D2 Viper and D2 Boa or HR Micro Amp, while the other amps have a larger more open soundstage vs the V1. Listening via the USB DAC for the entire review, despite being somewhat forward sounding there is still a good sense of space and ambience - but there is a little less transparency than with the Predator or other amps, like watching through a clean window instead of an open window. It does seem to be a little more micro-detailed than the Headstage Lyrix USB DAC or iBasso D1 USB DAC were. The V1 DAC is also not as smooth sounding as the Pico (or the other amps to some degree), but I wonder how much of that is the Pico and other amps being less forward and not having the slightly more pronounced upper mids (2KHz-8Khz) of the V1.
A nice loud but enjoyable volume level setting with HD600 and the Macbook is about 11-1 o'clock, depending on the program material. I find listening to most music at 2 o'clock is too loud for me, and 3 o'clock just starts to clip a little with no change going higher than 3 o'clock. Again, I would likely never want to listen loud enough to clip with HD600. The V1 has no problem driving the HD600, and the same volume at 11 o'clock with the V1 needs 1:30 o'clock in high gain with the D2 Boa. 5 o'clock (max) on the Boa is like 1:30 - 2 o'clock on the V1, and it sounds like the V1 can double the power of the Boa by 3 o'clock (sounds a good 3-4 db louder). On quiet classical music with wide dynamic range, this is a big plus over the Boa and stock D2 Viper.
This amp really seems to have some nice synergy with the HD600, and for $99 is a screamin' deal for you HD600 owners. It makes the HD600 sound good with all types of music - even if the Predator and Pico are a little better, they may not be $400 better for many people. The D2 Viper with rolled opamps and 2MOVE and Micro Amp are also slightly better with HD600, but still 2-3x the cost. This is a $99 amp that competes well with $170-180 amps driving HD600 (Stock Viper, Boa and Headstage). But switching from HD600 to the RS-1 (APS V3 cable and bowls) while I was listening to Jack Johnson is where those prominent uppers mids (2KHz - 8KHz) become more noticeable. After a few hours with the HD600 and stock cable, switching to the RS-1 with APS V3 cable was almost a shock to me.
As mentioned before, with the V1 fresh out of the box and driving the RS-1 I had to EQ out about 3 db at 2, 4 and 8Khz, but with the stock HD600 I needed NO EQ. After 164 hours of burn-in I had found that the amount of EQ needed with RS-1 and bowls had decreased to only removing 1 or 1.5 db at those frequencies, which is when I switched to burning it in without the DAC (so no EQ). Hoping to be able to make due without any EQ, I decided to get my ears acclimated to the RS-1 by listening to only the RS-1 for a while. I also switched to some non-vocal jazz music again - Guinea Pig "Kool Kats".
This was much less glaring, and the sax, trombone, trumpet, bass, drums and cymbals sounded much better and I could enjoy it with no EQ at all; although the EQ would bring it more in line with the other amps. Switching to Tsuyoshi Yamamoto "Smooth Jazz Festival" 'Somewhere Over the Rainbow' had the saxophone sounding a little edgier than the Predator, Pico or Boa until I applied the EQ again, although I could enjoy it without EQ. Pianos on this Tsuyoshi Yamamoto were not quite as enjoyable without the EQ as the other music. Moving back to some vocals with Shelby Lynn "Just a Little Lovin" (once my ears were acclimated) I found it sounded better with no EQ. But Jack Johnson still sounded a bit edgy. Most Jazz and Classical as well as electronic and new age sounded fine with the RS-1 and bowls driven by the V1, and for those albums that didn't sound their best, using the mild EQ brings them into balance and then it sounds very good with RS-1.
A light bulb went off in my head, and I switched the RS-1 back to flats like I tried whn out of the box, and voila - much better! This also helped somewhat with the lower mids coloration that I heard. I definitely prefer using the Grado flat pads with the RS-1 and V1 amp, which reduced ANY need for EQ of the upper mids. At this point the RS-1 became much more enjoyable with the V1, and it was almost up to the level of the D2 Viper and Boa with the RS-1, but not quite. Jack Johnson was now pleasant with no EQ. Even with the flat pads, many classical recordings such as "Handel's Messiah" still retained a good sense of space and ambience, despite the smaller soundstage with the flats. In doing the volume comparisons using RS-1, I found that a volume setting of 11 o'clock on the V1 with Infected Mushroom corresponded to a 1 o'clock in high gain on the stock D2 Viper. 12 o'clock was quite loud and rockin' with the V1 and electronica!
Switching to the Ultrasone Edition 9, the V1 was back in its element again, and paired well with these headphones. I enjoyed the V1 with the Edition 9 as much as I enjoyed it with the HD600, although I noticed the Pico has more bass with the Edition 9 than the V1, as did the Predator, D2 Viper and Boa. A little experimentation showed me that I can play the V1 louder with the Edition 9 without being over-whealmed with bass (which is easy for me due to my chronic tinnitus, which wasn't helped any by firing a firearm at a charging bear two weeks ago). However one of the advantages that the Edition 9 have over other my headphones is not having to play them loudly to get a good frequency response and liveliness. With Edition 9 and some music like Infected Mushroom "Dancing with the Kadafi" from the B.P. Empire album, I thought the V1 was better than the Pico, but with live jazz and classical music on the Edition 9 I found the Predator and Pico were the best again, followed by the Micro Amp and the two D2 amps. I don't have the loaner 2MOVE to compare, and didn't have time to roll the D2 Viper opamps again.
Typically with the Edition 9 and Pico, Viper or Boa the normal listening level is with the volume knob at 10 o'clock in HI gain, and it is at 9:30 with the V1. The Predator HI gain with Edition 9 puts the volume knob at about 9 o'clock! As a point of reference, medium gain on Predator puts the volume at 10 o'clock and low gain puts it at 12 o'clock.
I do not have my Denon D2000 while they are being re-terminated as balanced 4-pin (with SE adapter), so I tried my 600 ohm AKG K240M that used to be owned by Stevie Wonder (eBay seller bought them from his ex-wife, and he was selling all kinds of stereo equipment and DAT with brail dots on them, and they smell like his hair gel
Next were IEM. I switched to Klipsh Image X10 IEM which can be a little harder to drive vs my high sensitivity Custom IEM's. The volume for normal listening was 9:30 on the V1, and by 10 o'clock it was moderately loud volumes and higher than I typically listen at. 11 o'clock was louder than I will ever use, and clipping started at 12 o'clock with extremely loud volume levels. I hear no hiss with music paused until I get past 10:30 o'clock, so it isn't likely that I will ever hear hiss between songs when listening to the Image at loud volumes. With analog input and the music paused I don't hear any hiss until 11:30 o'clock (using iRiver H140). The power switch is built into the volume knob, like the Pico and Ibasso D2 amps, but there is less channel imbalance at low volume settings in the V1 vs those other amps - so I can play it very quietly with the Image X10 without problems, like when going to sleep or for background music. The D2 Boa could not play the Image quite as loud, and was clipping in low gain by 2 o'clock. I thought the V1 had good synergy with the Image X10, and was very enjoyable - tight strong bass, warm mids, crisp sparkly highs (using shallow insertion of the Image into ear canals). The lower mids were a little more pronounced with the Image on vocals than I liked, but were acceptable.
Last ones to try were my Freq Show custom IEM, which are so sensitive that I actually hear music with the V1 volume all the down and just above the power-on setting! I turned up the volume to 10:30 and heard hiss with the music paused, and backed down to 10 o'clock where the hiss went away. I un-paused the music and was blasted out of my skull by the loud music! I will never listen to the Freq Show at 10 o'clock, with 9 to 9:15 o'clock being a normal listening level and 9:30 to 9:45 is fairly loud. Again, I can play them very quietly without a channel imbalance, but not as quietly as I could the less sensitive Image. Still, it was acceptable for low level "go to sleep music" volumes.
The sound with the Freq Show was not bad with some music, very good with others, and a big problem with others - this being the fault of the IEM not the amp. Similar to the problems with using my Freq Show with the Meier Headsix or D2 with LM6172 opamp, vocals like Shelby Lynn "Just a Little Lovin" or Diana Krall "Girl in the Other Room" had the lower mids too pronounced and caused my ears to ring and roar. For those of you whom have read my reviews linked in my public profile (about me section), you know that with my ears the Freq Show are very picky about amps, and I almost returned these IEM for a refund. A few other people have reported the Freq causing ringing and roaring in their ears as well, not just me, although it is a very small minority of people. For example, my Headsix (lo gain) is great with Livewires but I didn't like it with my Freq; while Germania loved her Freq Show with her Headsix, so I do think it is "ear" dependent with these IEM. I picked these IEM for the review because they are popular and are the most fickle ones I own in regards to which amp I choose. With the Jack Johnson "Sleep Through the Static" they sounded good, and with non-vocal jazz and classical music I also have no problem with the resonance and ringing, but some (not all) acoustic guitar and piano music would ring in my ears too.
Again, THIS IS A PROBLEM WITH MY FREQ SHOW, not the amp - but the V1 amp doesn't help the problem any. This problem being uncommon to other people made me decide that it will not affect it's ranking below. I usually have to use either my Pico or Predator, or D2 Viper with rolled opamps for these IEM, or I have to play them very quietly if I don't have the right amp available. That being said, at very quiet volume levels like 9:00 - 9:15 o'clock then Shelby Lynn or pianos do sound nice with the Freq. My highly sensitive Livewires custom IEM are out in my car and not tested, but they sound good with every amp I have tried so I have no fear using them with the V1.
NEW AMP RANKING 09/08/2008 - Adding Vivid Technology V1.
Here is the ranking - see comments included if you haven't read the entire review:
1. RSA Predator (good bass and soundstage, more body, organic, full. Seems to do well with all my headphones, and not bad with any).
2. D2 with rolled opamps (LTC6241HV/LMH6622 sounds like 98% of the Predator with 7 hour battery life. LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. With my IEM I found it sounded best with the LM6172 and THS4032 swapped. This second opamp configuration was good with all my IEM, and not bad with my full size phones, except the RS-1 seem a bit bright and the Proline 2500 lacked fullness in the mids.)
3. 2MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1. It really seems to shine with my re-cabled Denon D2000, Klipsch Image, Freq Show customs, but doesn't sound bad with anything but my Proline 2500).
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off).
4. D2 Boa (Sonic signature slightly warmer than the Pico, and between the D2 Viper with LM6172 in the main amp (warmer) vs THS4032 in the main amp and LM6172 in the ground (cooler). Timbre and tone was good, and mids were slightly forward and rich, and highs had slightly less extension than the D2 Viper, Pico and Predator (in that order). The sense of space with live performances was superior with the D2 Viper, Pico and Predator (in that order), and LESS with the Boa at 300 hours of burn-in. However, the Boa did open up and gain more air and ambience on the level of the other top ranked amps by 575 hours of burn-in. Listening to Diana Krall "Girl in the Other Room" (Temptation and other songs) seemed to indicate more of a low mids hump than the other amps, which also caused problems with Pianos and realism on that CD. The problems reproducing this particular CD remained after 575 hours of burn-in, however with other CD's like Jazz at the Pawnshop, Handel Messiah and Tsuyoshi Yamamoto the D2 Boa demonstrated improved transparency and realism with the extra burn-in. And with other music it seems the bass extension is slightly less than the others in the top ranks, but by 575 hours of burn-in (with my RS-1) the 16Hz audio tones on Binks Audio Test CD were clearly audible, and the volume of the 20Hz tone caught me by surprise, while 25Hz was a little disorienting!
5. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241. The D2 Boa moved up a little with more burn-in, but it wasn't quite good enough to rise up to a 3rd place tie. So the modded D1 and everything else had to move down a slot. The D1 via USB isn't as good as via optical, which is why it is not tied with the D2 Boa after the Boa improved with extended burn-in. With optical input would beat the Boa easily.
6. Vivid Technology V1 (very good synergy with HD600 and AKG K240M 600 ohm, nice and fun with Edition 9 and Klipsch Image X10, acceptable with RS-1 IF switching to flats but bowls are not recommended, unacceptable with my Freq Show but not the amp's fault. DAC with slightly more micro-detal than stock D1 via USB or Headstage Lyrix, slightly less than either D2 Viper/Boa or the other amps. The most forward of all the amps. Can be near 3rd or 4th place with HD600 and 2nd with K240M, but 9th place with Grado RS-1 and bowls.)
6. D2 stock - tied (thin in the middle, neutral with good bass - it was sound signature and power but not level of detail that held it back with the stock opamps.) Sounds good with Freq Show and most of my IEM, fairly good with HD600 and Edition 9 but lacks power, not bad with RS-1 but can't properly drive AKG K240M 600 ohm. Sounds better with re-cabled modded ATH-AD900 than the Boa or V1.
7. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great with analog input.)
8. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 7th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 8th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
11/1/08 - iBasso D3 Python added:
I received the iBasso D3 Python review sample on 10/15 and started the burn-in right away, to reach 300 hours and do my review. I have used some popular headphones and the top 4 phones all have APureSound cable on them, including Grado RS-1, Denon AH-D2000, Sennheiser HD600 (silver mesh) and Ultrasone Edition 9. I also tested with Livewires custom IEM, and Klipsch Image X10 IEM. It sounded fantastic with everything, even right out of the box. Without any burn-in it sounded as good as my 1500+ hour D2 Viper with LM4562 opamp in the main socket and LM6172 in the ground.
I used 5xAAA Energizer batteries in the D3 and I got 123 hours out of the batteries before they became too weak to play loud without distortion today. The next set last 113 hours. The third set was Rayovac Hybrid NiMH long lasting re-chargeables which went over 96 hours on a charge (it was still running strong at 96 hours at 2am even though the LED had become dim, and it was dead at 10am when I got up). During burn-in I used my Denon D2000 with a pillow between the ear cups and listened intermittently each day, without a lot of changes during that time. I just finished charging the batteries, and with 332 hours on the D3 I am starting my review (10/29/08).
My first listening had been with Denon D2000 and this was the first time to try the Grado RS-1 with bowls, so I started there. I had previously compared the D3 Python out of the box vs my D2 Viper (see above) and felt I could not tell which was which with my eyes closed, so this time I started my comparison vs the D2 Boa (while the Viper and Predator are being charged). I put on some Shelby Lynn "Just a Little Lovin" and felt that the D2 Boa sounded nice. After 3-4 tracks on the Shelby Lynn album, I switched to Guinea Pig "Kool Cats", and Tsuyoshi Yamamoto "Smooth Jazz Festival", Jazz at the Pawnshop, Handel "Messiah", Arvo Part "Tabula Rasa", Sibelius (assorted), Infected Mushroom "B.P. Empire", We the Kings "We the Kings", Metro Station "Metro Station", and Jack Johnson "Sleep Through the Static". After that I just randomly picked music from my library that I wanted to hear.
Switching between the D2 Boa to the D3 Python produced a noticeable change - the soundstage opened up a bit and became bigger, and the highs brightened up a little. The D3 Python seems a little more clear and sparkly than the D2 Boa. The third thing I noticed was the D3 Python's seems a little more solid and focused than the Boa. This not to say the D2 Boa doesn't have treble presence or good bass, just that the D3 Python is better. The next thing I noticed was the D2 Boa at 800 hours has lost a little more of the lower mids hump that it used to have in female vocals - this brought it up to being less colored than before, and closer to being neutral like the D3. If you recall from previously, it took 600 hours for the Boa's soundstage to open up as much as it did, and it was still changing for a long time like the Predator which took 1000 hours - so it is reasonable to me that the D2 Boa sound has further improved with time. On the other hand, the D2 Viper only took 300 hours to fully burn-in, and the D3 Python seems like it needed even less time. Nevertheless, the D3 is an upgrade over the Boa in the areas I mentioned.
Next was comparing the D3 to the Pico, still with the RS-1. Now if you have read all of my review from the beginning, you will see that while I gave the Predator a slight edge in personal preference, I have always said the Pico was very good and I enjoy it (9.7/10 vs 10/10). I have also posted in another thread that the Pico's sound had become warmer after I put an additional 300-400 hours on it, after Asr had owned it and broken it in already. Most recently I had decided that I now like the Pico as much as my D2 Viper with rolled opamps, and have been planning to move it up to a second place tie. It's still my favorite to use as a USB DAC Pre-amp to feed a full sized amp. So while comparing the D3 Python to the Pico with the Grado RS-1 tonight I thought the Pico was slightly smoother in the upper mids - but in regards to soundstage and air and ambience and micro-detail I think they are on a very similar level, with only the very slightest edge going to the Pico. The upper mids did not cause trouble with the RS-1 and rock music like I had found with the Vivid V1, so it was still enjoyable with bowls or flats won the RS-1.
Switching to the Denon D2000 I felt the Pico's advantage in the smoothness of the upper mids went away. I have previously said I really like the Synergy between the Pico and D2000, and I think the D3 has it there in spades too. With the D2000 I can tell that the two amps do sound a little different - the D3 bass was slightly less in quantity than with the Pico (like maybe only 1 db), but maybe it was a little more taught with the D3 Python. Again, the soundstage remained open and airy with good detail; and with both amps and I could place Shelby Lynn and the various instruments on stage - same with other pieces like Jazz at the Pawnshop where the D3/D2000 combo was very transparent with excellent soundstage and instrument placement. Interestingly I was then surprised with some classical music where I found it a little bit too wide, where sometimes I felt the result left a hole in the middle (Sibelius: Finlandia, En Saga, Karelia Suite, Etc.). This didn't occur with the D3 and RS-1 or D3/HD600, or with the Pico and D2000 where I found a more cohesive soundstage from ear to ear with no hole. With Arvo Part "Tabula Rasa" the hole was much smaller in the center of the soundstage but not entirely gone. With Handel: Messiah the hole went away completely with the D2000, just by changing the program material. Since the issue wasn't apparent with the D3/RS-1 or D3/HD600, it is also possible that it's the fault of the D2000 since I haven't done the markl mods and stuffed the earpads to tilt the cans and drivers more. I would again put the D3 and Pico on about the same level with all my other program material, as it was difficult to find any other material that gave a hole in the soundstage with the D2000. One other test I ran was test tones since the D2000 has such excellent sub-bass, and the D3 has solid bass down to 20Hz with the D2000 (and 16Hz is audible).
Listening with the HD600 the D3 had good synergy and sounded very similar to the Pico again, and it has plenty of power to drive them to high volumes as well. The power output with these 300 ohm cans is very good, and better than the Predator and D2 Boa in terms of sheer clean volume. The power output with HD600 is very similar to the Pico and Vivid V1. I found nothing to complain about with the D3 and HD600, and would be happy to listen to the combo anytime. Female and male vocals are still very good like with the other headphones, and I liked the D3 with all genres out of the HD600. The bass was powerful but detailed, the mids smooth and the highs sparkly, just the way I like it. The D3/HD600 was just as exciting with Infected Mushroom "Dancing with the Kadafi" as with the Pico and V1 in my earlier reviews, and I could achieve the same volume levels with the D3 at 4 o'clock as the Pico at 3 o'clock, but past that either amp would start clipping. With the HD600 the D2 Boa was well behind in volume and punch, with at least 4-5 db less output. There were NO soundstage defects with the HD600, and the soundstage was centered in front of my forehead and running from in front of my head to inside of my head, and width was good as well. Again, this was reminiscent of the Pico soundstage. However, the Pico does still seem be a little clearer in the ambient cues and very slightly more detailed in complex passages.
With the Edition 9 I was really impressed with the D3 - it does a good job controlling the bass and defining it like with the D2000, so it doesn't over power the rest of the sound spectrum. It was clean and alive sounding, and very quick and punchy. Soundstage, tone, transparency and frequency balance are all a good match for the Edition 9. Normal listening levels were at 10 o'clock and it could play very loudly at 12 o'clock, reaching the same volume levels that I would achieve with the HD600 maxed out at 4 o'clock! Clipping would not begin until past 2 o'clock with the Ediiton 9, at volume levels much higher than I could ever use, and I could feel my ears and jaw shaking at max clean volumes - thank God for the ear plugs! The Pico still manages to out-power the D3 with Edition 9, by probably a noticeable 2 db louder, even though they could both play to the same volume with HD600.
The last ones to try were some IEM. I felt the D3 was very good with my Livewires, SE530 in Custom Shells, Freq Show and Klipsch Image X10. However, I could easily hear that the D3 is picking up some RF interference from NORAD and Cheyenne Mountain that are in my backyard, along all the local radio station towers are up the mountain too! I could actually hear FM stations being picked up by the D3, which made it very difficult to use with IEM and USB. With my iMod or analog input there was no such RF interference, and it only occurred with a USB cable plugged into the back of the D3, even if not connected to a computer. And it was only heard with headphones plugged into the amp when the amp is turned on, but not heard in the DAC line out. I had a similar problem with my Meier HA-1 Mk2 headphone amp, but only with headphones plugged into the low impedance headphone jack, and sure enough this RF improves in the basement like the HA-1 did when I moved it there. I will be taking my amps to a Colorado Head-fi meet Saturday 11/1 in Denver, and will listen again for any RF interference, but I'm pretty sure the fault is Cheyenne Mountain - because of them we had to change all of our garage door frequencies because NORAD was blocking the remote door openers.
Fortunately it only occurs between 8 o'clock and 9 o'clock on the volume knob, almost like the D3 uses an active volume control. And it gets better in some parts of the house where the radio towers that are on the mountain behind my house don't seem to reach as well. I hadn't noticed it before because I was only using the volume between 9-12 o'clock to listen to music with full size headphones. None of my other amps pick up radio stations, but the D3 Python and D2 Viper are also very susceptible to chattering from my iPhone if it is anywhere near the amps.
Finally - Ranking, with a caveat: I want to first clarify a little about some changes my personal tastes and preferences. One big area that is becoming more important to me over time is not just having those rich warm seductive mids for vocals and saxophone or other acoustic instruments, but also having good transparency with larger soundstage and good ambience and space, ALL AT THE SAME TIME. My home amps have spoiled me and I am becoming more demanding in my expectations as well.
Summarizing what I was thinking previously - The 2MOVE that I initially ranked slightly above the Pico was very detailed and warm and rich. But it lacked some space and air or ambience vs many of the other amps, creating a more forward intimate setting that I REALLY dug at the time I reviewed it. Some of this soundstage was due to the amp section itself, as feeding it with a better DAC still felt more close and intimate (just not quite as much). I do not have a 2MOVE anymore to compare to the D3 DAC, but I do have most of the other amps that I previously compared the 2MOVE against. Having listened to all of them again (except 2MOVE), I think that at this point I am happier with the Pico than I would have been if I had owned the 2MOVE. As a matter of fact, I haven't used my Meier Headsix in months, which has a similar sound signature and soundstage as the 2MOVE. I have been using the Predator, Pico and D2 Viper the most out of all of them.
Now, the Predator via DAC was more spacious than 2MOVE, while the Pico would project an even bigger more spacious and airy soundstage above and beyond all the others. The D2 Viper with the first round of rolled opamps (LM6172/THS4032) was in between the Pico and Predator in rank, but closer to the Predator in soundstage - what I considered a good compromise. The whole reason the Pico fell behind the others despite it's audibly superior DAC was the lack of fullness in the lower mids and the way a hard strike on the piano keys would bite my ears. Both of those problems were not audible when using it as a DAC/pre-amp instead of driving headphones - but when I listen with headphones now, those issues have also improved over the months since my initial review (the same ones as back in March).
However, the old D2 Viper top-pick opamp combo had a problem with sucking down the battery in 7 hours, and with being too forward with many of my IEM, allowing the Pico to pass it up with IEM. So I made changes and currently the D2 Viper has the LM4562/LM6172 in it, which is more clear and open and spacious (plus battery life climbed from 7 hours to 17). I would say it is now closer to the detail and space and ambience of the Pico, and I would put the D3 in that category as well. This is good, because they are also rich and not thin sounding in the mids. Seriously, the Predator, Pico and D3 are just so close that I might be ready to be put out to pasture and give up doing these reviews - but I still put the Predator just slightly ahead in how it conveys the emotion of the music in it's tone, although I like the soundstage and space of the Pico a little more.
So, even if the 2MOVE were here today I suspect that I would rank the Predator first, followed closely by a tie for second with Pico, D2 Viper (LM4562/LM6172), and Micro Stack, and I'd have the 2MOVE as a close 3rd. I suspect that all along I should have placed the 2MOVE there because otherwise I would have bought one by now (my 2MOVE loan was way back in April). That leaves me in a quandary as to where to put the D3 Python because while I like it very much, the RF problem makes it difficult for me to place it higher ranked than those in 1st - 3rd place above. And it can't tie with the Pico because the Pico also now has a very slight advantage of smoother upper mids with the RS-1, and slightly more ambient cues and micro-detail in complex passages.
At this point, while sounding closer to my second place picks when I can find a quiet spot in my house, I have to say it is tied with 2MOVE in 3rd. Although I'd rather listen to D3 than 2MOVE at this stage of the game, the RF interference wont let me rank it higher. I recognize that the RF is due to my particular location, and it may not affect anyone else out there like it has for me (will find out tomorrow). Such are the hazards of putting together a subjective review like this, when based on their technical merits either none of them are losers and personal preferences can change, or where personal preferences makes one decide to ignore technical faults. It was like Goldilocks saying this bed is too hard, and this one is too soft, but this one is just right. Who am I to say what you "sleep number" should be. I do think I need to be approaching any reviews in the future with a more objective eye (or should I say, ear), as I feel I am losing some of that here.
Nevertheless, I am now considering parting with the D2 Viper because the D3 sounds just as good, has 7x more battery life, and it also sounds great as a DAC-only when I feed a full size amp (without needing any batteries). While the D2 Viper can be made to sound similar to a Predator with the right opamps, and closer to the Pico with others, the D3 Python splits the difference well enough that it doesn't matter. Despite the nice DAC in the D3, I'm pretty sure right now that the D3 will spend most of it's time replacing the D2 viper as my "iMod amp". The Predator remains paired with my 3G Nano as the combo is pretty wicked sounding for such a small package. And the Pico will continue to be used the most with my Macbook and either powering headphones or used as a DAC/preamp feeding a desktop amp. If it wasn't for the nasty RF problem in my neighborhood caused by the radio towers right behind my house, I'd maybe use the D3 for the macbook instead because of the improved battery life.
UPDATE 11/6/08: Cannot fit the ranking in the first post after the D3 review without exceeding the 100,000 character limit. See 01/04/09 or newer rankings in the second post.
UPDATE 12/15/08 - CANNOT FIT MY FULL NUFORCE ICON REVIEW BELOW INTO THE FIRST POST, EXCEEDING 100000 CHARACTER LIMIT - SEE SECOND POST FOR FULL BODY OF NUFORCE REVIEW:
HEADPHONES USED: Westone 3, Klipsch Image X10, Denon C700, Nuforce NE-7M, ATH-ESW10JPN, APS V3 cabled HD600, APS V3 cabled RS-1, APS V3 cabled markl Woodied Denon D2000, and APS V3 cabled Edition.
MUSIC USED: Michael Knowles "Bink Audio Test CD", Nils Lofgren "Acoustic Live", Arne Domnerus "Antiphone Blues" and "Jazz at the Pawnshop", Infected Mushroom "B.P. Empire", Tord Gustavsen Trio "Being There", Pat Metheny "Day Trip", Tsuyoshi Yamamoto "Autumn in Seattle" and "Smooth Jazz Festival", B.B. King and Eric Clapton "Riding With the King", Shelby Lynn "Just a Little Lovin'", Nora Jones "Not Too Late", Arvo Part "Tabula Rasa", Jack Johnson "Sleep Through the Static" and "In Between Dreams", Elaine Elias "Something for You", Gary Karr "Super Double-bass", Guinea Pig "Kool Cats", Christopher Hogwood "Handel Messiah", Pink Floyd "DSOT", The Beatles "Love", Beck "Sea Change", Diana Krall "Girl in the Other Room", Coldplay "Viva La Vida", and Skillet "Comatose".
The Nuforce Icon Mobile is a $99 entry level portable USB DAC/Amp, which has more of a flat form factor that is amenable to being stacked under an iPod without adding too much size to the overall package. It is about the same width and depth as the iBasso D2 Boa, but almost half as tall/thick, so you can almost stack two Icon Mobile on top of each other to achieve the thickness of one D2 Boa. When plugged into the Macbook's USB port the DAC shows up as a "C-Media USB Headphone Set". The Nuforce has some unique features including two headphone out jacks which switch on the power when a headphone plug is inserted, with the jack closer the center being a special jack that works with 4-conductor headsets with stereo headphones and a built-in microphone, like the Nuforce NE-7M iPhone IEM (or other iPhone IEM). This allows the NE-7M to be used as a headset with telephony applications, instant messaging and Skype, and probably for gaming as well. I have not been able to test this telephony feature, but the mic did show up in my Mac's Audio MIDI setup application as the left channel only microphone. The analog input is on the same end of the amp as the two outputs (we'll call it the top end), and all three jacks are slightly recessed by about 0.5 mm along one edge of the amp...
Post is too large to edit... SEE POST #2 FOR THE FULL REVIEW and RANKING - http://www.head-fi.org/forums/3947073-post2.html
UPDATE 01/04/09 - XM5 USB DAC Amp by Practical Devices Corporation CANNOT FIT REVIEW INTO POST #1, FULL REVIEW IS IN POST #2:
I used my usual playlist of lossless songs and typical rotation of headphones with the XM5, and I really like the XM5 - the quality of sound it puts out deserves the $245-$325 that it sells for (depending on options like optional BUF634, or AD8397 kit, or Li rechargable vs Alkaline). Based on the sound, I assume this dual mono amp has to be a major upgrade from the XM4, not just an evolution. It comes stock with a pair of OPA134 opamps, which are single channel opamps, and it has a pair of buffer sockets for improved current output by using optional BUF634 chips, or another opamp like AD8397 in the buffers. It come standard with using a 9v alkaline battery (50 hours), and a charging circuit for rechargables is optional (40 hours).
SEE POST #2 FOR THE FULL REVIEW and MOST RECENT RANKING - http://www.head-fi.org/forums/3947073-post2.html
RANKING: I HATE THE RANKING BECAUSE NOW I HAVE TOO MANY 3RD PLACE TIES, ALTHOUGH FOR DIFFERENT REASONS, and I would not wish to part with any of the amps in 3rd or higher because they all have an area where they excel. (except D2 Viper which could sound like a Predator or a Pico but was redundant with poor battery life and was sold). Anything in 4th and below is expendable, even if very good sounding. I previously moved the 2MOVE to 4th because I couldn't remember how good it sounded, having not listened to one in months. Now I have a 3MOVE which sounds like a 2MOVE with an upgraded case, and I can fix my ranking. See additional comments included if you haven't read the entire review:
1. RSA Predator (good bass and soundstage, more body, organic, full. Seems to do well with all my headphones, and not bad with any. Gobs of power with RS-1, D2000 and Edition 9 but Could use a little more power with HD600 - very underpowered for AKG K240M 600 ohm. DAC is not as good as the Pico, but the sound of the amp makes up for it)
2. D2 Viper with rolled opamps (with LM6172/THS4032 - balanced, not too forward, sweet/magical Saxophone, almost mesmerizing like Predator. With my IEM I found it sounded better with the LM6172 and THS4032 swapped. This second opamp configuration was good with all my IEM, and not bad with my full size phones, except the RS-1 seem a bit bright and the Proline 2500 lacked fullness in the mids. With LTC6241HV/LMH6622 sounds like 98% of the Predator with only 7 hour battery life. Later I discovered the LM4562 main/LM6172 ground, and this works very well for full size phones and IEM - very open and spacious and detailed, sounding closer to the Pico without losing any warmth or rich tone. And battery life was bumped from 7 hours to 17 hours!)
3. PICO (smooth and transparent without coloration, Great DAC, won the bad mastering Diana Krall test, but nothing special with piano and sax like the others, too neutral as an amp - how is that possible, maybe not because there is something around 2Khz that is not right with RS-1. It really seems to shine with my re-cabled Denon D2000, Klipsch Image, Freq Show customs, but doesn't sound bad with anything but my Proline 2500). Over the past few months the Pico has really been growing on me, and it no longer seems to lack warmth with my RS-1 or other headphones (especially since I sold the PL2500). The DAC's space and ambience and soundstage still stand out as slightly superior, as before, and it seems to do well with most IEM but not all)
3. Headroom 2006 Micro Stack Portable (a twin to the Pico's sound but better with piano, too BIG and out of production, with crossfeed mids are richer/warmer but highs rolled off).
3. 2MOVE/3MOVE (sweet mids and saxophone, midbass hmmm, failed the bad mastering diana krall test, great detail and air, too large and heavy, sounds as good as Pico but it's a different sound, sometimes too forward. NO iPhone Buzz. Auditory memory fades as I hadn't listened to the 2MOVE since April, so I bought a B-stock 3MOVE and found I do still enjoy it very much. Since I am liking open and spacious sound a little more now, the Pico moved up to tie the 3MOVE rather than move the 3MOVE down. I did add listening to the Westone 3 with this amp and they are fantastic together. 3MOVE is a better match for the D2000 and RS-1 than XM5, while I liked the XM5 more with HD600, Edition 9 and ESW10, even though 3MOVE had more power for HD600)
3. Practical Devices XM5 (amp section better than D3 and rivals higher ranked amps, but DAC not as good as the D3 - so it evens out. Gets along better with more of my headphones than D3 and with all of my IEM, and I am having no iPhone buzzing with it so far. A chameleon - many times it sounds like my Predator, and other times it sounds more like the 3MOVE, and the amp section really shines with iMod or an external DAC)
4. D3 Python (very sensitive to RF interference from Cheyenne Mountain and NORAD. The sound is very close to the 3rd place amps, and I like it very much, being only slightly less smooth in the upper mids with Grado than Pico, and very slightly less micro-detail in ambient cues and complex passages, dropped in rank because of RFI problems)
5. Nuforce Icon Mobile (More forward than D2 Boa and closer to Vivid V1 and 2MOVE in that regard, has good synergy with Westone 3, Klipsch X10, Nuforce NE-7M, Denon C700, ATH-ESW10, D2000, and Edition 9 - sounded nice with HD600 but a bit under powered with HD600 and not worth trying with 600 ohm AKG K240M. With RS-1 occasionally had a similar upper mids coloration like Vivid V1 and sometimes needed to switch to the flats to enjoy them more, so not first choice for Grado but would not avoid the amp because one owns Grados, good midrange detail but not as full and rich sounding as the top tier amps above except with D2000, Edition 9 and Westone 3 which bring that to the table on their own)
5. D2 Boa (Sonic signature slightly warmer than the Pico, and between the D2 Viper with LM6172 in the main amp (warmer) vs THS4032 in the main amp and LM6172 in the ground (cooler). Timbre and tone was good, and lower mids were slightly forward and rich, and highs had slightly less extension than the D2 Viper or Pico and Predator (in that order). The sense of space with live performances was superior with the D2 Viper, Pico and Predator (in that order), and LESS with the Boa at 300 hours of burn-in. However, the Boa did open up and gain more air and ambience on the level of the other top ranked amps by 575 hours of burn-in. Listening to Diana Krall "Girl in the Other Room" (Temptation and other songs) seemed to indicate more of a low mids hump than the other amps, which also caused problems with Pianos and realism on that CD. The problems reproducing this particular CD remained after 575 hours of burn-in, however with other CD's like Jazz at the Pawnshop, Handel Messiah and Tsuyoshi Yamamoto the D2 Boa demonstrated improved transparency and realism with the extra burn-in. And with other music it seems the bass extension is slightly less than the others in the top ranks, but by 575 hours of burn-in (with my RS-1) the 16Hz audio tones on Binks Audio Test CD were clearly audible, and the volume of the 20Hz tone caught me by surprise, while 25Hz was a little disorienting! With over 800 hours the lower mids hump is less noticeable with female and male vocals now, but the middle mids and upper mids now seem to be more withdrawn instead.
6. D1 with rolled opamps (AD797 main/LM6643 buffer/LT6234 DAC - powerful, punchy, energetic, alive - not as bright as AD743/6643/6241. The D2 Boa moved up a little with more burn-in, but it wasn't quite good enough to rise up to a 3rd place tie. So the modded D1 and everything else had to move down a slot. The D1 via USB isn't as good as via optical, which is why it is not tied with the D2 Boa after the Boa improved with extended burn-in. With optical input would beat the Boa easily.
7. Vivid Technology V1 (very good synergy with HD600 and AKG K240M 600 ohm, nice and fun with Edition 9 and Klipsch Image X10, acceptable with RS-1 IF switching to flats but bowls are not recommended, unacceptable with my Freq Show but not the amp's fault. DAC with slightly more micro-detal than stock D1 via USB or Headstage Lyrix, slightly less than either D2 Viper/Boa or the other amps. The most forward of all the amps. Can be near 3rd place with HD600 and Edition 9 or 2nd with K240M, but 8th place with Grado RS-1 and bowls and last with Freq Show)
8. D2 stock - tied (thin in the middle, neutral with good bass - it was sound signature and power but not level of detail that held it back with the stock opamps.) Sounds good with Freq Show and most of my IEM, fairly good with HD600 and Edition 9 but lacks power, not bad with RS-1 but can't properly drive AKG K240M 600 ohm. Sounds better with re-cabled modded ATH-AD900 than the Boa or V1.
8. Lyrix (good frequency balance, DAC lacking details and air vs the others, but the amp is great with analog input.)
9. D1 stock opamps (put AD823/NE5532/AD8616 back in right before I shipped it back for the 2-3db channel imbalance, too edgy and bright and distant. Very close to 7th as a DAC/Amp because the DAC is so good it makes up for the frequency response issues. Clearly 8th if only using analog input. NOTE - my V1 opamps were from the initial run, and iBasso updated the opamps to V2 in November 07 to make it better than Lyrix.)
I should note that any of these amps are very pleasing sounding.
Feb 22, 2009 UPDATE - iBasso D10 REVIEW AND REVISED RANKING:
This 1st post is at the limit - see review in post #2 below: UPDATED 01/04 REVIEW 12 USB DAC amps - Predator, Pico, 2/3MOVE, D3 D2 Viper/Boa D1, Lyrix, MicroAmp, Vivid V1, Nuforce, XM5 - Head-Fi: Covering Headphones, Earphones and Portable Audio
Jan 29, 2010 UPDATE - iBasso D4 IMPRESSIONS, PENDING FULL REVIEW. Will try to post a more complete review in post #2 as soon as I can. At this point, I put the D4 in my top spot for features and sound combined, although if battery life along with a high end DAC is important to you then the D10 still makes more sense.:
FIRST IMPRESSIONS - http://www.head-fi.org/forums/6146137-post932.html and http://www.head-fi.org/forums/6147003-post934.html
D4 vs D10 and others, with opamp rolling - http://www.head-fi.org/forums/6264269-post962.html
More Comparisons - http://www.head-fi.org/forums/6274204-post972.html
