Feb 22, 2009 UPDATE - iBasso D10 REVIEW AND REVISED RANKING:
The 1st post in the thread is full - this was added to post #2 under the Nuforce and XM5: UPDATED 2/22 REVIEW 13 USB DAC amp - Predator, Pico, 2/3MOVE, D10 D3 D2 Viper/Boa D1, Lyrix, MicroAmp, Vivid V1, Nuforce, XM5 - Head-Fi: Covering Headphones, Earphones and Portable Audio
The iBasso D10 is an evolutionary product that takes the best of what they have had to offer over the past year and a half, and all crammed into one little box. My first amp from them was the D1 back at the end of August 2007, which basically took the chipset of the Headroom Micro Stack (separate DAC and Amp) and put it all into one package at a fraction of the size. Yet it was still too big for true portable use. I enjoyed that amp and moved it to my bedside where I could use it as a DAC for my tube amp. And with new opamps it was a real contender, but only via optical (or coax) input and not as good via USB. With stock opamps the original D1 probably could be described as poor via analog input, although significantly improved with a set of AD743 or AD797 in the main amp (on a 2:1 adapter) with AD8397 or LMH6643 as buffers, and AD8656 or LT6234 in the DAC section. Because the Headroom Micro DAC has a much better sounding USB DAC, and better sounding line out, I traded my D1 for some electrostatic equipment and bought a Headroom to replace it. Something I regretted later because of the D1 high quality optical DAC and smaller size.
After the success of the D1 iBasso introduced the D2 Viper which was a limited run of 100 amps with socketed opamps so that the main opamp and ground channel opamp could be changed to tune the sound. It's main feature was an improved size and superior USB DAC section, using I2S between the USB receiver and DAC, and upgrading the DAC chip from the CS4398 to the Wolfson WM8740 (like the Pico). It shipped with an LT1364 in main amp and NE5532 in ground, and while it outperformed the stock D1 it didn't outperform the "rolled" D1. However, changing the opamps to LM6172 main and THS4032 ground turned it into a giant-killer, and opamp combos to mimic the Predator and the Pico were found as well. Co-developed at the same time as the D2 Viper was the D2 Boa that was meant to be the same amp but smaller, and it eliminated the socketed opamps due to size constraints. I have suspected that if not for the insistence of several head-fi members that the D2 Viper may have never made it to production, with the D2 Boa being the final product instead. While the Viper ran at 12v for only about 15 hours, the Boa runs on 5v for about 35-40 hours and could be charged by the USB Port. The sound was better than the stock D2 Viper, but not up to the level of the D2 Viper after it received new opamps.
The D3 was developed to fill the spot in sound quality left vacant by the discontinued D2 Viper, including the need for more power than the 5v in the Boa, and the ability to swap batteries by frequent travelers - it runs on 7.5v with 5xAAA replaceable batteries. The D3 sounds much better than the D2 Boa, but still not quite as good as the D2 Viper with the right opamps. A nice new feature was the ability to use it as a DAC with line-out only and no batteries needed, like the 2MOVE and 3MOVE when used as a DAC/amp without batteries. Unfortunately the D3 headphone out was still better than the line-out; but it could be used as a DAC preamp with good results, at the expense of using up the batteries. It's biggest problem to me was the susceptibility to RFI from the iPhone. Still, for 2/5 of the cost of a Pico or Predator it was a good bang for the buck if one wanted a DAC/amp with bigger soundstage and more detailed DAC than the 3MOVE, despite a less powerful and slightly less refined amp section.
In the meantime, for reasons unknown to me the D1 was discontinued after the D2 Boa was released, and that left a gap in the product line in my eyes. I was excited to hear that a new upgraded and smaller version of the D1 was being developed, and when it was released I ordered the same day it was up on the website. This is an amp that is only 1/2" longer than the D3 with the same height and width (and 1" longer than the D2), but manages to cram an additional Optical and Coax input along with the USB and analog input of the D3, plus a charging circuit that like the D2 Boa can be charged by the computer's USB port, while still retaining the line-out function of the D3 and it's Wolfson DAC. For all of us with current day macintosh computers, discontinued portable CD players with optical out, or discontinued iRiver H120 and H140 MP3 players with optical out could again have a small portable solution for DAC and amp.
In this photo you can see the D10 Cobra on the bottom is about 1/2" longer than the D3 Python sitting on it, which is about 1/2" longer than the D2 Boa sitting on it, which is about 2/3" longer than the Pico on the top. I will get some more pictures this weekend and post them.
Main Features (per iBasso website):
- PCM2906, converts USB into a S/PDIF signal
- CS8416, DA-receiver chip
- WM8740, D/A chip
- OP+BUF structure for amplification
- 2-Setting Gain Switch for impedance matching (+3/10dB)
- Dedicated MCU (Micro Controller Unit) to manager inputs, outputs, and functions.
- Flexible input and output compatibility. It has USB, optical, coaxial, stereo input, line out, and stereo output
- Works as a combo or a stand-alone AMP, DAC, USB soundcard
- Built-in rechargeable Li-polymer battery plays up to 30 hours (30 hrs for AMP, or 20hrs for combo)
- Measures 55*21*104mm, and weights 168g
- Comes with power adapter, leather pouch, optical cable, USB cable, warranty card, owner¡¯s manual, and opamp rolling kit. (includes AD8656*2, LMH6643*2, Dummy adapter*2)
As you know, the amplifier ranking can actually be a bit different depending on the headphones being used at the time, so I had to do detailed comparisons of multiple amps using multiple headphones and it takes longer and longer with the more amps and headphones I have. With the D10 included, I still have 10 of the 13 amps that have been reviewed! (minus Lyrix, D2 Viper and D1). I just can't listen to 7 or 8 headphones on 10 amps in quick succession in a way that I can remember the previous combination's sound, so I have to make some compromises.
So, I narrowed down the D10 comparisons to only vs the top tier amps where the D10 belongs, and I compared it only to the top 4 amps that don't sound alike and were the most enjoyable = Predator, Pico, 3MOVE and XM5. At one point late in the review I got a loaner Apogee Duet to dompare it to as well. I can skip most of the others from previous reviews for a variety of reasons: I know where the D3 stands vs the Pico (almost the same but slightly less) and where the Micro DAC/Amp stands (pretty much the same as Pico). I didn't need to do a side by side with D2 Boa, Vivid V1 or Nuforce which are below the top tier for reasons mentioned previously in my reviews.
I used my RS-1, D2000, HD600, Edition 9 and ESW10 as my full size phones, and I used my Westone 3 and ES3X plus Phonak Audeo as my IEM for the review. I first want to say that the D10 is a good match for any of these headphones, and there was not one that stood out as not getting along with it, even with the stock opamps that were installed. In addition to listening via USB, I found it was very good with my iMod portable (modded ipod), so unlike the D1 it is good out of the box with analog input while the D1 needed new opamps to sound good with analog inputs. And it was very competent via USB as well, but even better with optical as I discovered later. Anytime I did testing via optical I made sure my Macbook pro was set for 24/96 output, as several of the music files I used were native 24.96 files. Lastly, I also tried the DAC line-out and used it as a DAC/pre-amp via headphone-out vs Pico as a DAC/Pre-amp for my Woo GES/Stax O2 rig as well.
With no burn-in at all and right out of the box, using the stock opamps, and listening via USB it sounded as good as my 600-700 hour D3 via USB in a side by side comparison (I stopped counting after 600 hours). At 55 hours (with optical) D10 had slightly grainy highs vs Pico, but was very detailed and spacious like the Pico. By about 215 hours it had become more refined sounding and I felt that the D10 fed via optical out of a Macbook ranked up there with the top DAC/amps like the Headamp Pico, RSA Predator, Meier 3MOVE and such. I had passed my 300 hour mark set for burn-in the morning of 2/9/09 and over the course of the review I have over 400 hours on the D10 now. The Majority of my review was done with the stock opamps. During the initial evaluation period, I was happy to discover that the D10 has very good channel balance at low volume knob positions with IEM, and it is dead silent when music is not playing and it is connected as a DAC/amp to the computer. There is no hiss with high sensitivity IEM like the Macbook headphone out, while high end DAC/amp like the Apogee Duet has a very slight hiss with my Westone ES3X customs and Livewires or SE530 customs.
I started my initial listening with USB via RS-1, D2000 and HD600, and first compared it to the Predator. Listening to the D10 and Predator Via USB, and going back and forth between them, I was unable to tell any significant differences in the sound signature other than the Predator has a little less power to drive the HD600, was less detailed, and the Predator's soundstage was flatter than the D10. This was a very long listening session and by the time I was done it was the middle of the night and I was tired, but in subsequent comparisons I felt the D10 was still up to the level of enjoyment that I get from the Predator. So, it seems the D10 sounds as good as the Predator to me but the D10 USB DAC is more detailed and spacious than the Predator.
I then compared the iBasso D10 optical input vs Predator USB input the next night, using the Phonak Audeo IEM with grey filters and silicone tips while listening to CD's ripped lossless into ALAC format. This particular IEM setup is a more demanding test in that the Phonak with grey filters and silicone tips can be ruthless in revealing details, and usually need the Complys foam tips to smooth out the treble which can sometimes be bright. I often find the grey filters are a little harsher sounding with the silicone tips (or can border on sibilant), and almost always use the large Complys tips (which I had to buy separately). I wanted to see if any of the amps were more forgiving of a demanding and detailed IEM, and to see how much more detail was available via optical instead of USB.
When I used the D10 via optical I could have 3 amps connected to the Macbook Pro at the same time with two via USB, allowing me to quickly switch between the amps. I rotated the Predator, Pico 3MOVE, and XM5 through the two USB ports, and then also listened to the D10 via USB again. With this particular IEM setup the Predator was slightly smoother in the highs than the D10 Optical, 3MOVE USB or XM5 USB. The Pico was also very smooth and refined, and with this particular IEM setup I have to say the Pico DAC/amp combo is tied with Predator for smoothness when the Phonak have the wrong combination of filters and tips. Going back to the usual Complys T130 foam tips I felt all the amps became smoother with improved bass, so that is really an IEM issue and I should not have been using the silicone tips in the 1st place. In this round of testing the D10 optical does seem to have more micro-detail than all but the Pico (with 16/44 music). It seems the D10 DAC ties with the Pico as the most detailed and spacious while being smooth at the same time (except in mismatched IEM tips and filters). This held true with listening with the Westone 3 and ES3X as well.
I then tried the D10 DAC to feed another portable amp, using line-out and headphone out. I plugged the D10 line-out into the Predator using a nice quality ALO 22g Cryo Silver X mini-mini and the D10 was connected to the Macbook via optical and USB, but I also left the Predator connected via USB. This way I was able to flip the front panel switch to switch between the built-in DAC or the D10 DAC while switching the computer at the same time. The D10 line-out volume level matches closely the Predator's USB DAC line level, so the volume of the amp did not change with changing the source. With 16bit/44khz lossless ripped CDs, the D10 line-out into the Predator sounded better as a source than the Predator using it's built-in USB DAC, which sounded slightly flatter and less lively, regardless of whether the D10 was used with optical or USB. Switching to the D10 headphone-out to drive the Predator woke up the sound a bit, similar to what I heard with the D3 line-out function previously - both the D3 and D10 DAC's line-out seem slightly less alive and vibrant than their headphone out when feeding the sound into another amplifier. This was confirmed when comparing the D10 line-out to several desktop DAC at a recent mini-meet, where I only used line-out instead of the headphone out (there were also issues of different interconnects and digital cables and inserting a pre-amp and listener fatigue and severe lack of time).
I then put on three different albums with higher quality 24/96 bit rates in lossless (Ryan Adams and the Cardinals, and Portico Quartet, and Arnie Somogyl's Ambulance) and listened again. The D10 optical DAC into the Predator was superior with more micro-detail and ambience and air between instruments, and while the Predator via USB sounded good the soundstage was flatter and smaller than with the D10 optical. This improvement was still there even when feeding the inferior D10 line out instead of headphone out into the Predator. The D10 handles native 24/96 files well, while the older D1 could not decode digital signals greater than 24/48 via optical (Mac audio midi setup was set for 24/96 via optical before launching iTunes). With the computer still set for optical out and using the D10 DAC, swapping the headphones from Predator over to the D10 (and unplugging the mini interconnect) switched the sound to the D10 headphone out, and resulted in very little change in the sound when the headphones were driven by the D10 instead of the Predator. Basically, the D10 via USB matches or exceeds the Predator's performance as a DAC/amp, and via optical it beats it in detail and resolution with 16/44 or 24/96 files.
I then did some comparisons with the Pico vs D10. In many songs such as with an Elaine Elias song "You and the Night and the Music", some of the cymbals strikes or other notes die out just a little faster with the Pico and there is more quiet or blackness between the notes than with the D10. It's like with the D10 optical I can hear a little "deeper" into the music and hear more of the quiet stuff going on in the background and between notes, and I don't mean noise floor but rather the decay of the instruments and echos hiding in there. This gives the illusion that the notes start and stop slightly faster with the Pico, making it sound a little snappier. I find that the D10 as a DAC/amp and the Pico (and Duet) have a larger sense of space and ambience than the Predator, 3MOVE or XM5 which don't use the Wolfson WM8740 DAC like these two.
Similar to my DAC test vs Predator, I also tried feeding the D10 as a DAC line-out (and headphone out) into the Pico, and compared it's DAC to the Pico's built-in DAC (removing the amp section from the equation). The D10 headphone out volume needed to be set at 3 o'clock in high gain to get the output volume to match the Pico USB DAC volume when flipping between them. When using D10 line-out the volume was much softer and while I listened to the Pico in low gain via it's built-in USB, when switching to D10 as the DAC with its line-out feeding Pico I had to switch the Pico to hi-gain to match the volume of the Pico's USB input. The D10 line out is softer and quieter than the internal USB DAC of the Pico, which was not the case with the Predator. I found The D10 optical and the Apogee Duet via firewire were both slightly more detailed with native 24/96 files than the Pico, but the differences were much less with 16/44 music (almost negligible). So, the optical D10 line-out when fed native 24/96 did pull away slightly from the Pico, where the USB makes the Mac down-sample the music to 16/44, and then the Pico has to up-sample it back up to 24/96. But otherwise, with 16/44 files the advantage was minimal if any.
As for other areas of the sound, the D10 as an amp sounds slightly warmer than the Pico, and after getting used to the sound via D10 as a headphone amp, switching to the Pico can sometimes sound slightly thinner - the same effect I experienced almost a year ago when I was comparing the Pico to the Predator. Sometimes I think the D10 sound falls between the Pico and Predator, but with having the resolution and space of the Pico. I feel the musical performance via the D10 as a complete package sounded a little fuller and "bigger" than the Pico, despite having a little less power than the Pico for the HD600. It could still get loud with HD600, but was optimal with RS-1, D2000, Edition 9, ESW10, and all my IEM. When not pushing the D10 amp to the max, the sound signature seems just a little closer to a desktop amp to me, like the Predator, although neither one has the power of a desktop amp (or even the power of the 3MOVE and Pico). With the RS-1, D2000 and Edition 9 the D10 volume can go extremely high. With HD600 it is about as powerful as the D3 and XM5, and more than the D2 Boa or Predator or Nuforce. But the Pico and V1 are still more powerful, and the 3MOVE is the king of power with the HD600 (in hi-output mode). I am still amazed at the volumes I can get with the 3MOVE and HD600.
I did another comparison (which I repeated on 2/14 with Sherwood), comparing the D10 and Pico as USB DACs feeding my Woo GES and listening with Stax O2 Mk1 and Mk2. This rig is where the Pico gets used the most. The D10 via optical and feeding the line-out signal into a Woo GES desktop amp was very close to the Pico doing the same, and at the meet Sherwood didn't even notice the very small drop in detail and space when I switched the D10 from optical to USB when he wasn't looking (listened to D10 optical feeding the GES, then USB Pico, and then back to D10 but via USB instead). I found that it is easier to hear the drop in sound quality switching the D10 from optical to USB when one is looking for it. Nevertheless, the D10 USB DAC is at least as good as the D3 USB DAC that was so close to (but slightly below) the Pico previously. At one point the D10 DAC line-out output wasn't high enough for the low-gain GES. So I switched the D10 to headphone out into the GES, like I must do with the Pico, and I noticed an improvement in dynamics and soundstage which I assumed was from the higher gain. Further testing shows this is a slight improvement in sound from headphone out vs line-out when the D10 is used to drive another amp.
I want to mention that at the same meet last weekend, where Sherwood and I compared the D10 vs Pico as a DAC feeding a full size amp, we also tried comparing D10 to several desktop DACs. That didn't turn out as well. We had 6 DACs connected to an NAD542 via an S/PDIF distribution center via Coax with a mish-mash of digital cables, and a variety of interconnects feeding the DACs outputs into a Presonus central Station, and then fed the output of the Presonus to 3 electrostatic amps with a variety of cables and listened with 5 electrostatic headphones. Now that I look at it, there was no way to get all 5 listeners hearing the same thing, nor could we put the DACs on a level playing field. The test showed the line-out is not as dynamic and spacious (5 out of 5 people agreed) as the 5 desktop DACs. But, I don't recall the D10 ever sounding that flat and "un-dynamic" before. So I had to wonder if we did something wrong because we had clearly earlier in the day shown the D10 to be a match for the Pico as a DAC/Pre-amp. I wonder if part of that DAC shoot-out result was due to the difference between line-out and headphone out, but still, when connected directly to the amp it is feeding, the D10 DAC line-out is pretty good.
And, as far as I can tell the D10 via USB is MUCH better than the USB in the older D1 was - the D1 USB feeding another amp was closer to the $40 Headstage DAC cable feeding another amp (although D1 USB sounded better when feeding its internal amp). I also find that the D10 optical input DAC is a little better sounding than the D1 optical was as I remember it, because this D10 DAC is closer to the Micro DAC and Pico than the D1 was. In general, listening to the D10 via optical is like like mixing the best traits of the Predator and the Pico together, and even via USB I enjoyed it as much as the Predator and Pico or Duet. I believe it tops the sound of the D3 Python and the D2 Viper with rolled opamps, and is the best DAC/amp that iBasso has put out so far.
As I have reported problems with RFI from the iPhone causing a GSM Buzz with other amps, I listened for that issue as well. Fortunately the D10 does not pick up radio stations from the towers behind my house like my D3, and the RFI "buzz" from iPhone is less than with the D3 as well (and more like the RFI with my D2 Boa = mild but livable). The D10 is also less sensitive to RFI with nothing plugged into the USB port on the back of the amp, and the iPhone Buzz responds well to changing the opamp to an AD8656 and using a Quick Bridge Solutions - EM Shield for iPhone
EM blocking card.
The ability to change or "roll" opamps is a nice feature. The D10 comes stock with an AD4841-2 in the main amp socket, and a pair of AD708 in the buffer sockets (all dual channel opamps, not single). They also include a small case with two AD8656 opamps, two LMH6643 opamps, and two dummy opamps for bypassing the buffers. I also have a large supply of opamps from my time rolling opamps in the D1 and D2 Viper, so I tried a variety of opamps with the D10. There are several that sound good, including an AD8066 with the AD708 buffers, AD8397 with the buffers bypassed (using dummy opamps that are included), and AD8656 with bypassed buffers. The AD8656 and 8066 have nice large/spacious soundstages and refined sound, and the AD8656 still puts out a lot of power without any buffers and can get loud enough with HD600 at max volume knob setting, without any clipping. Using the AD8656 does get a little brighter with any buffer I tried, including 2x AD708, LMH6643 and AD8656. I had a third 8656 left from my D1 kit (it will blow if used in the main amp socket of the D1), but I didn't like it enough with three 8656 to use anything but the one 8656 by itself. I have not had a chance to try any of the other opamps with two 8656 as buffers. Using the buffers did seem to add just a little more volume to the 8656, but then the D10 would clip before the volume knob would hit 5 o'clock. So far my two preferred setups are the stock one, or the AD8656 with bypassed buffers. I only started rolling opamps on 2/21 and the AD8656 is what is in it now, for the final few hours of my review. I left the D10 connected to USB with the switch flipped to charge for 2 weeks, to see how it would do in a desktop rig where it is plugged in and on all the time. Tonight I unplugged the USB and left it running via optical with the AD8656 opamp and bypassed buffers to test battery life. I will report on this later, so that I can post this review now.
To me there seem to be three tiers of portable headphone amps (examples are ones I have heard):
1. the "Don't bother with this if you don't have to" group = E3 and Boostaroo (add power but subtracts from the sound, narrow soundstage, or rolled off frequency response, or all of the above).
2. the "Good bang for the buck but with compromises" group which are not good for everything, but great for some things = includes Travagans Colors, JSeaber Cmoy, Caffeine Pro, Vivid V1, Nuforce mobile, D2 Boa and Stock D1 or stock D2 Viper.
3. and the "Wow, this is getting closer to a desktop amp" (usually in sound but not power). These have more presence and body to the sound and are more refined, and there are very few phones they don't work well with = includes Pico, Predator, 3MOVE, XM5, D3 Python, D2 Viper with rolled opamps, D1 rolled and D10 stock or rolled, Headsix, TTVJ, Micro Amp. The Lyrix Total is an odd one out because the Amp sounds like a top tier and the DAC is a middle tier. The D10 now joins this group, and I put it at the top of my list for now.RANKING: I HAD HATED THE RANKING BECAUSE I PREVIOUSLY HAD TOO MANY 3RD PLACE TIES, ALTHOUGH FOR DIFFERENT REASONS, and said that I would not wish to part with any of the amps that were 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). Now I am attempting to split out some of the ties and have more rankings with fewer ties.
With the latest ranking with fewer ties and a new 1st place, anything below 5th 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. Then I bought a 3MOVE which sounds like a 2MOVE with an upgraded case, and I fixed my ranking. See additional comments included if you haven't read the entire review:1. iBasso D10
Great sound that blends the performance of the Predator and Pico, with a USB DAC that falls between them and an optical DAC that exceeds theirs. Ability to roll opamps and tune the sound, convenient charging via USB port, Decent power for even HD600 and good low volume channel balance for IEM.2. 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)3. 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!)4. 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 to other USB DAC, as before, and it seems to do well with most IEM but not all)4. 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. 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)5. 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)6. 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)7. 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)7. 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.8. 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.9. 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)10. 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 V1.10. Lyrix
(good frequency balance, DAC lacking details and air vs the others, but the amp is great with analog input.)11. 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.
ADDENDUM - Some people aren't clear about the differences between optical and USB vs other USB DAC amps, or the differences in sound between line-out of the D10 to feed another amp vs D10 headphone-out to feed another amp as a preamp. While the D10 headphone out is more dynamic and lively than the slightly flatter sounding line-out, the line out is still very good when feeding another amp, and beats the Predator's DAC and closely matches the Pico's DAC, but beating it with native 24/96 music. The only time the line-out did not compare favorably was in a comparison to several desktop DAC in a shoot out that I think involved poor scientific method - where they didn't all use the same digital and analog cables between the source, preamp and power amps, and where all the listeners were using different headphones and amps.
I believe I reported that I thought the D10 optical DAC sounds about as good as the Headroom, and both optical DAC were a little better than the Pico when they were all driving portable amps. I also thought I said that the line-out was better in comparisons to other portable USB DAC in most cases, just that the headphone out was even better, and the optical on top of either was even better. It gets confusing because I listened to the D10 with (1) it's own DAC and amp with USB and optical, and then listened to the (2) Predator and (3) Pico with their own DAC. And I also listened to Predator and Pico with them being feed by the D10 DAC with (4) optical and (5) USB, using both line-out and headphone out to feed the Predator and Pico. In total that's 12 combinations of DAC and amp, as listed below!
D10 optical > D10 amp
D10 USB > D10 amp
Predator USB > Predator amp
D10 optical headphone out > Predator amp
D10 optical line-out > Predator amp
D10 USB headphone out > Predator amp
D10 USB line-out > Predator amp
Pico USB > Pico amp
D10 optical Headphone out > Pico amp
D10 optical line-out > Pico amp
D10 USB headphone out > Pico amp
D10 USB line-out > Pico amp