jamato8
Headphoneus Supremus
I have been waiting for one of these for a few years and I have to admit I am too excited. I use a portable CD player with an optical out but no one has made a portable unit that would work with this so I had to make my own. Now I do have the Monica II dac, which is excellent but I would love to have something like the D1 also and it will work out of a computer using the usb as well. I also like the quality look of this unit, at least so far from what I can see in the images.
Here is the link: iBasso D1 Portable DAC/AMP
470uf capacitor for the buffers bypassed with a 4.7uf Black Gate nonpolar
All Black Gates and one Sanyo Oscon, You do not have to use Sanyo caps. You can use all Black Gates just check the physical size and measure the caps you are replacing. I would use as much uf as the original or more and make sure of the voltage. The higher the voltage of the cap for the same uf, generally the larger the cap so I stay near the operating voltage as I have also found that with electrolytic type caps they sound better when near the operating voltage where film caps often are better at much higher voltage ratings.
My world traveling soldering iron. I bought this in China for 2.50$. I like it better than my Weller that cost 15 times as much and the tips are easier to change though I can't get the tips here. I bought one extra tip but the first one is still fine.
Finally. I love stuff like this. :^)
I emailed them and the price is around $229.
The opamp it uses is the AD823 and the buffers are 5532. Its all about implementation so I am looking forward to hearing this.
This is the company I use for extremely good optical cables. You can order them with toslink to mini, mini to mini, toslink to toslink and whatever end to end length you want. The fittings are aluminum and the work is excellent. They will also use heat shrink if you request to make a very scecure bond of the optical cable to the connector. It is a good bond to begin with but I wanted/needed something even stronger for my mobile use and they figured out a method of angling the optical out of the connector to give more a a curve. They also have a neat adapter so you can go right angle with the optical. They are in Canada and ship within a day of the order normally.
For a great optical connector both in price and quality I use connectors from Sysconcept of Canada. I have used this companies connectors for years and have always had good customer service and communication. There are mini to mini and mini to toslink cables available and right angle adapters: Here is the link:
Mini to mini:
Sys Concept Inc. Fiber Optic Products Attenuators, Patch cords, Laser Diodes, Connectors, MP3, Toslink, Hybrid Adapter and more: MiniPlug to MiniPlug Premium Optical Cable 0.05 to 50 meters
Toslink to mini:
Sys Concept Inc. Fiber Optic Products Attenuators, Patch cords, Laser Diodes, Connectors, MP3, Toslink, Hybrid Adapter and more: MiniPlug to Toslink Premium Optical Cable 0.05 to 50 meters
email: info@sys-concept.com
***Optional Opamps to use***
To further help with opamp and buffer combinations I have added the following as posted by HiFlight on 9 15 07:
""This evening I tried both the AD8397 and the LM4652 in the buffer sockets. The 4562 sounds better with the 2111, but I like the 8397 better with some of the other opamps. The 2111/4562 appears to be very synergistic! My personal preference, YMMV. Earlier today at the minimeet, Miguel had the 5532s as buffers and I had the 8397s in mine. We then compared a variety of other opamps in LR. Our preferences differed in our favorites for LR.
The AD8656 was the winner in the DAC socket.
It wasn't until after the meet that we tried the 4562 as a buffer. I was not sure it would work out, as the output power is MUCH less than the 8397, but I misjudged it, apparently.
What fun!!!!""
9 18 2007
Well my D1 is sounding better and better. I have replaced the coupling caps for the dac putput with Black Gate HiQ 47uf caps, the power supply cap for the low pass opamp with a Sanyo 150uf SG and the coupling caps for the amp section with Black Gate 47uf HiQ. All but two caps now are Sanyo for the digital section and Black Gates for the analogue section.
The solder as I have noted before is very hard. If you use some normal solder to mix with it, it is much easy to wick up and work with. I was able to melt the solder and glide the cap leads into the hole without cleaning all the solder from the board. Cleaning all the solder is hard because some of the solder is still hard and doesn't wick well but when mixed you can wick some and heat the rest to allow the cap leads to go throw the hole.
9 19 07
ince modifying the D1 with Black Gates, and the settling/forming of these caps (I used some caps that had already been in a circuit so the forming of these Black Gates thankfully had already pretty much been done) the amp has taken on a very high end musical sound that I can not believe. I am glad that it is as big as it is so that I have room for the Black Gates and that there is room to change opamps and that it has a design that appears to be very good or the sound would not be at the level it is no matter what I do.
Edit: The D1 has taken on a nice 3D presentation with very good spatial information and transparency.
Posted by Hiflight on 9 19 2007
"OPA2111: Very wide and expansive soundstage, very dimensional.
AD8066: Strong bass, good mids, good soundstage depth.
ADA4841-2: Well balanced throughout the spectrum, sweet highs.
They all work very well with both buffers, just a matter of individual taste. The differences are relatively small, with subtle tonal and soundstage variations. The 8397 is slightly more assertive, the 4562 somewhat more intimate.
These should not be considered as the only opamps that sound good in the D1. They are simply my personal ranking. There are many others I have tried that also sound very good.
For those interested in experimenting with different opamps other than those listed above, I would encourage ordering a modest assortment of opamps directly from a distributor and determining ones own individual preferences.
It is very difficult to try to express verbally the subtle differences in SQ between several different opamps. What I hear and describe may be totally different than what someone else perceives.
I can positively state that the improvements in both the DAC and amp sections of the D1 after modifications from stock are very apparent, even to the casual listener; furthermore, these improvements are apparent regardless of which phones I am using.
I should point out that as one improves the sonic quality and accuracy of any amp, it becomes less tolerant of poor source material or components!""
***Optical cables from Sys Concept
On the optical cables my measurements are just the cable but not the connector ends, which of course also add length. With the shortest I mention there is just enough length for a U and about 2cm from tip to tip on the U. this would allow for a iRiver or like device sitting on the D1. If you get it in toslink to toslink and get two of the right angle adapters, which work very well, you can have a short U not projecting out but lying along side of the ends of the D1 and iRiver. Or you could also get a mini to toslink (I got both) in the shorter length and have the U extending on out from the back of the units. I wish now I had gotten a tos to tos and ppurchased two 90 degree adapters. I also go the longer length in both toslink and mini to allow for a little more separation, though not much, or a different component with a toslink or mini out to the mini in of the D1. There, how is that. :^)
The shortest length, end to end as specified by Sys. Concept is 9.5cm and the longer one I got is 13.5 from one end to the other end of the entire optical cable including ends.
***A great extra battery for many uses for the D1 and other portable electronics is the Tekkeon MP3450, which is an all contained battery and charging unit. I bought mine at Costwonder on Ebay.
Posted by HiFlight on 10 5 2007:
Info for Opamp Rollers!
There have been considerable posts recently regarding which is the "best" choice of opamp, as well as discussion regarding the possibility of delaying ordering the D1 until iBasso comes out with a "better" or "best" configuration.
That will NEVER happen! It is relatively easy for me to pick 5 or 6 good choices, but even when several of us really "hardcore" rollers get together for a mini-meet, we rarely agree on which sounds "best". My favorite is rarely the same as the others in attendance, and it often results in each individual favoring a different opamp.
It is even more difficult for iBasso to arrive at a configuration that will please everyone, as they have issues such as cost, availability and battery life to consider. They may choose to develop something entirely different, such as an amp that has an exterior power supply, or even a different circuit configuration. They will not, I can say with certainty, find one opamp that will be a magic bullet for everyone!.
Many feel that using different opamps in amplifier will result in coloration of the sound. Technically speaking, perhaps this is correct, but all music is colored to some degree or another by room acoustics, hall size, speakers or headphone characteristics, and even by our own personal physiology among other things.
Everyone has their individual preference for sound quality, such as "punchy" bass, lots of "presence", smoother highs, etc, etc, etc.
These are all simply different shades of coloration, and no one opamp will satisfy everyone, just as no specific brand of source, amp or phones can be called the "best".
I would suggest simply trying several different opamps and see how they sound. It is easy, relatively inexpensive, and one will undoubtedly find a configuration that sounds the BEST to you!
I have tried to suggest, based on many trials and combinations of opamps and benchmarked for sound quality against one of my high-end tube amps, to post a selection of opamps that will perhaps eliminate some trial and error in the selection process. I always consider battery life and reliability along with sound quality, as these are every bit as important as other factors when choosing a possible replacement for the factory defaults.
Please don't ask what is the BEST, because there is not an answer that will suit the tastes of all listeners!!!
Any of the opamps mentioned in previous posts as good swaps are fine choices, but in the end, the "best" choice is what YOU like!!!!
Posted by HiFlight on 10 6 2007 on opamps:
********My personal favorite D1 configuration
Either the ADA4841-2 or LTC6241HV as LR with LMH6643 as buffers.
All 3 are only available in the SOIC configuration and need to be soldered onto adapters.
Posted by HiFlight on 10 7 2007
*********Low current draw=long battery life
I have found a very nice-sounding opamp combination that draws only 14ma total for all 5 opamps, (1DAC, 1L/R and 2 buffers) compared to the stock configuration that draws approx. 40 ma. In comparison, the OPA2111/LM4562/AD8656, while a fine-sounding combination, draws about 43ma.
This should result in significantly longer battery life even when using the full DAC/Amplifier combination.
Tonal balance, soundstage and detail are very good, with a clean, open sound.
The following are the opamps I used in this configuration:
L/R: ADA4841-2
Buffers: LMH6643
DAC: LT6234
One can substitue the LT6234 or the LTC6241HV for the ADA4841 with little audible difference. Also the ADA4841 works quite well in the DAC socket in place of the LT6234.
There are slight differences in the sound when changing LR opamps, but please do not ask me which is best. They are very close, and the choice will largely be determined by the choice of music, headphones, and personal preference.
I do find that with these combinations the sound quality is VERY close when switching the same source (iRiver H120) between the D1 Aux input and the Optical input, which tells me that the quality of the amplifier section is now equal to the quality of the DAC.
If using the D1 primarily by battery power rather than with an adapter, one might wish to try some of these low-current draw opamps.
10 10 07 Opamp Update by HiFlight
HiFlight's latest...
--------------------------------------------------------------------------------
by HiFlight 10 12 2007
In the ongoing but elusive search for musical perfection the rolling continues!
The following configuration is probably one of my personal favorites:
LTC6241HV L/R
LMH6643 Buffers
LMH6643 DAC
All 3 are SOIC and need adapters.
For those who might be interested in additional details, please PM or Email me.
Opamp Datasheets
For those opamp rollers who might be interested in researching some of the technical specifications of many of the opamps we have mentioned on this and other threads, I am reposting below a list of opamp datasheets I originally posted as a "Sticky" on the Xin forum.
*******************************
http://hjem.get2net.dk/tkhifi/data-blade/ad744.pdf AD744
http://www.analog.com/UploadedFiles/...eets/AD746.pdf AgnD746 (dual)
http://ist-socrates.berkeley.edu/~ph...iles/ad743.pdf AD743
http://www.analog.com/UploadedFiles/...eets/AD746.pdf AD746
http://www.analog.com/UploadedFiles/...751AD797_d.pdf AD797
http://www.onsemi.com/pub/Collateral/NE5534-D.PDF NE5534
http://focus.ti.com/lit/ds/symlink/opa228.pdf OPA227/228
http://www.uib.es/depart/dfs/GTE/sta...ETT/OPA604.pdf OPA604
http://www.ociw.edu/instrumentation/...rts/OPA627.pdf OPA627
http://www.ociw.edu/instrumentation/ccd/parts/AD829.pdf AD 829
Analog Devices AD843 - 34 MHz, CBFET Fast Settling Op Amp AD843
http://www.analog.com/UploadedFiles/...eets/AD823.pdf AD823
http://ezphysics.nchu.edu.tw/prophys...eet/lt1028.pdf LT1028
http://www.linear.com/pc/downloadDoc...26,P1293,D1612 LT1115
http://www.acoustica.org.uk/t/naim/d...mps/ad8610.pdf AD8610
http://www.analog.com/UploadedFiles/...156OP275_c.pdf op275 (dual)
http://tinyurl.com/avy7k OP285 (dual)
http://www.analog.com/UploadedFiles/...22AD8397_0.pdf AD 8397 (dual)
http://focus.ti.com/lit/ds/symlink/opa2134.pdf OPA134, 2134 (dual)
http://www-micrel.deis.unibo.it/DATA_SHEETS/OPA128.pdf OPA128
http://www.fulcrum.ru/Read/CDROMs/TI...cs/sbos140.pdf OPA2111 (dual)
http://www.ociw.edu/instrumentation/...rts/LT1365.pdf LT 1364 (dual)
http://www.schuro.de/Daten/Burr%20Brown/OPA2107.PDF OPA2107 (dual)
http://www.analog.com/UploadedFiles/...D8065_8066.pdf AD8066 (dual)
http://www.soundlabsgroup.com.au/mm5..._datasheet.pdf AD825
http://tinyurl.com/ya9qbr AD822
http://www.analog.com/UploadedFiles/...1-1_4841-2.pdf ADA4841-2 (dual)
http://focus.ti.com/lit/ds/symlink/ths4032.pdf THS 4032 (dual)
http://www.analog.com/UploadedFiles/...ets/AD8599.pdf AD8599 (dual)
http://tinyurl.com/25le6o LT6234 (dual)
http://cache.national.com/ds/LM/LM4562.pdf LM4562 (dual)
http://cache.national.com/ds/LM/LME49720.pdf LME49720 (dual)
http://tinyurl.com/kpyrz AD8566 (dual)
http://tinyurl.com/j6kz8 AD8616 (6v !) (dual)
http://tinyurl.com/ehwcs AD8656 (6v !) Solid Tube (dual)
http://www.tranzistoare.ro/datasheets2/50/502419_1.pdf LTC6241HV Solid Tube WV (12v) (dual)
http://tinyurl.com/ykfqh5 EL8201 (Buffer) (6v !)
http://tinyurl.com/yh33gc AD8531 (Buffer)
http://tinyurl.com/yelsjy TLV4111 (Buffer)
http://focus.ti.com/lit/ds/symlink/buf634.pdf BUF634 (Buffer)
http://cache.national.com/ds/LM/LMH6642.pdf LMH6643 (Buffer) (dual)
http://www.asmeltec.de/dl0az/datasheets/HA5002.pdf HA5002 (Buffer)
http://eshop.engineering.uiowa.edu/N...3/DS012336.pdf LM6171 Buffer
__________________
10 27 2007 Post from Ron Hiflight
Try this one!
Not content to leave well-enough alone, I decided to make some adapters using the Browndog single to dual DIP adapter to mount some of my opamps that I had used in my Xin amps and see if my all-time favorite for my SM-IV, the AD797, sounded as good in my D1.
I bypassed the buffer sockets with plug-in sockets that jumpered the input/outputs of both buffers, rendering them a straight wire. As the AD797 has a pretty good current output and extremely low noise as well as nearly perfect square-wave response, I figured that buffers would only downgrade the sound. I found this to be the case in the D1 as well as in the Xin amp.
It is a very tight fit when putting in the 2-1 adapter for L&R, and requires bending a couple of caps to the side a small amount in order to seat the Browndog.
The resulting sound was certainly worth the effort, as it is even more spectacular in the D1 than in the SM-IV, due to the fact that the D1 seems to be very stable, even with fast opamps. At any rate, the sound is very full and warm, with deep fundemental bass that one can almost feel, especially when running an optical input. Trebles are clean and crisp with no excessive brightness or sibilence. Soundstage is very natural, with instrument placement very solid and stable.
I would say that the SQ is very similar to that experienced with high-end tube amps
Due to space limitations on the 2-1 adapter, it is not possible to use 2 browndog mounted SOIC opamps, however most of the ones I used successfully in the Xin were of DIP configuration.
Rather than solder the opamps into the adapter, I soldered 2 standoff sockets onto the adapter, thereby making it quick and easy to change opamps while leaving the adapter in place.
If one really wanted to use browndog mounted SOIC single-channel opamps, the sockets could be soldered to the adapter at a slight angle, providing a little more room, however I doube that I will be trying too many other opamps, as I really like the sound of the bypassed 797s.
To summarize, if interested in trying this combo, one needs a 2-1 single to dual Browndog adapter (DIP), 4 sockets, 4 jumpers, and 2 AD797 DIP opamps. Soldering the sockets onto the adapter requires soldering 8 small pins that in are close proximity to each other. Solder bridges are NOT good! Once the sockets are done, the rest is quick and easy.
**** Quote from HiFlight
"I like more power and higher slew rate for buffers. AD8397 and LMH6643 are hard to beat for buffers if you need to drive low-impedance phones.
For higher impedances and especially if they are pretty efficient phones, the LME49720 is a very nice sounding opamp buffer. They have limited output power though."
Then in a sperate post, or PM (I forget)
"LMH 6643 is [another] choice for the buffer sockets, making the choice for buffer:
AD8397: (bold, works well for rock, most output power)
LMH6643: Smooth, warm, nice with bright phones)
LME49720: Nice frequency balance, superb soundstage. Great choice for instrumental and complex harmonies."
Ron Kerlin
From a post by Dual:
Heres some DIY dummy opamps I just cooked up to bypass the buffers for the AD797.
They are very simple to make all you need to do is short pins 1-3 and 5-7 on the socket with some thin metal wire.
You don't even need to solder them in if the wire is a tight fit but do so anyway just to be safe.
I perfer the AD797 with bypass buffers than with 2x AD8397.
12 24 07 post by musicmaker:
After several permutations & combinations of LR, buffer, DAC opamps, I have found a combo that sounds the best to my ears.
LR: AD797, buffers: bypassed & DAC: LT6241
12 25 07 by musicmaker:
Here are the opamps I've tried:
OPA2111, AD797, LMH6643, LM4562, LT1364, LT6241, LT6234, AD8656, AD8397, AD8599, LME4972 & stock of course
1 9 2008 Pete7
I did do a little more comparing with the D1 amp section and the P2. This time in the D1 I used THS4032 with the LMH6643's (which come stock now) as buffers, and in the P2 I used THS4032 in L/R and LT4236 in 3/4. The P2 definitely sounds like the better amp, although the difference isn't all that noticeable unless you really look for it. With the P2 the sound is a little more textured and detailed, and the soundstage is closer, music a little more impactful. Both sound terrific, and if I had to give a percentage difference between the two it would be like 3-4%. I think I'm giving AD797's a break in both units as now I want a more balanced sound. The THS4032's seem to have a little more in the highs. The AD797's with the buffers bypassed sounded pretty decent in the D1, but with my ES2's it sounded a little dark.
1 24 2009 HeadphoneAddict
If the new ones come with 6234 in DAC, LT1364 in L/R and LMH6643 in buffers, there isn't a huge reason to change anything.
Mine had AD8616 in DAC stock, and the AD8656 was much better, while the LT6234 was an additional upgrade above that.
Mine had AD823 stock, and I tried the OPA2111 withAD8397 in the buffers and it was a noticeable upgrade, but then I tried the AD797 in L/R with those AD8397 in buffers, and the sound is tremendous.
You should take out the LMH6643 from buffers and try the AD8397 with the AD797 - you get great smooth detailed highs, warm forward mids, and tight quick strong bass. With the opamps I have in it now it sounds very much like my P2 did, and everyone agrees the P2 is a great sounding amp.
1 29 2008 Posted by HiFlight
Winner and still champion!
After all the months spent rolling opamps and various cap mods to my D1, I finally went back to an opamp I had used very successfully with my Xin amps..the AD743.
This was my favorite opamp when most of the amps were designed for single-channel opamps. I had almost forgotten about it.
The AD743 is not well-known in audio circles, as it is primarily designed for sonar applications. Nontheless, it is smooth, accurate, and has great low-end depth and impact; it also renders all types of music with a very lifelike and realistic soundstage.
I am using the 743 with the LMH6655 buffers. I feel they are a bit more accurate than is the LMH6643.
My top 3 opamp choices for the D1 are: AD743 (single), AD797 (single), THS4032 (dual)
The 797 has more bass, the 4032 has more detail and transient response, but the 743 is just overall "right" to me.
1 31 2008 Haymaker18
To take a page from Hiflight, the AD743 and LMH6655 just "sounds right"
Unlike some of the others, I can't really describe a particular strength of it because it doesn't sound colored or unbalanced to me...just natural and right.
Here is the link: iBasso D1 Portable DAC/AMP
470uf capacitor for the buffers bypassed with a 4.7uf Black Gate nonpolar
All Black Gates and one Sanyo Oscon, You do not have to use Sanyo caps. You can use all Black Gates just check the physical size and measure the caps you are replacing. I would use as much uf as the original or more and make sure of the voltage. The higher the voltage of the cap for the same uf, generally the larger the cap so I stay near the operating voltage as I have also found that with electrolytic type caps they sound better when near the operating voltage where film caps often are better at much higher voltage ratings.
My world traveling soldering iron. I bought this in China for 2.50$. I like it better than my Weller that cost 15 times as much and the tips are easier to change though I can't get the tips here. I bought one extra tip but the first one is still fine.
Finally. I love stuff like this. :^)
I emailed them and the price is around $229.
The opamp it uses is the AD823 and the buffers are 5532. Its all about implementation so I am looking forward to hearing this.
This is the company I use for extremely good optical cables. You can order them with toslink to mini, mini to mini, toslink to toslink and whatever end to end length you want. The fittings are aluminum and the work is excellent. They will also use heat shrink if you request to make a very scecure bond of the optical cable to the connector. It is a good bond to begin with but I wanted/needed something even stronger for my mobile use and they figured out a method of angling the optical out of the connector to give more a a curve. They also have a neat adapter so you can go right angle with the optical. They are in Canada and ship within a day of the order normally.
For a great optical connector both in price and quality I use connectors from Sysconcept of Canada. I have used this companies connectors for years and have always had good customer service and communication. There are mini to mini and mini to toslink cables available and right angle adapters: Here is the link:
Mini to mini:
Sys Concept Inc. Fiber Optic Products Attenuators, Patch cords, Laser Diodes, Connectors, MP3, Toslink, Hybrid Adapter and more: MiniPlug to MiniPlug Premium Optical Cable 0.05 to 50 meters
Toslink to mini:
Sys Concept Inc. Fiber Optic Products Attenuators, Patch cords, Laser Diodes, Connectors, MP3, Toslink, Hybrid Adapter and more: MiniPlug to Toslink Premium Optical Cable 0.05 to 50 meters
email: info@sys-concept.com
***Optional Opamps to use***
To further help with opamp and buffer combinations I have added the following as posted by HiFlight on 9 15 07:
""This evening I tried both the AD8397 and the LM4652 in the buffer sockets. The 4562 sounds better with the 2111, but I like the 8397 better with some of the other opamps. The 2111/4562 appears to be very synergistic! My personal preference, YMMV. Earlier today at the minimeet, Miguel had the 5532s as buffers and I had the 8397s in mine. We then compared a variety of other opamps in LR. Our preferences differed in our favorites for LR.
The AD8656 was the winner in the DAC socket.
It wasn't until after the meet that we tried the 4562 as a buffer. I was not sure it would work out, as the output power is MUCH less than the 8397, but I misjudged it, apparently.
What fun!!!!""
9 18 2007
Well my D1 is sounding better and better. I have replaced the coupling caps for the dac putput with Black Gate HiQ 47uf caps, the power supply cap for the low pass opamp with a Sanyo 150uf SG and the coupling caps for the amp section with Black Gate 47uf HiQ. All but two caps now are Sanyo for the digital section and Black Gates for the analogue section.
The solder as I have noted before is very hard. If you use some normal solder to mix with it, it is much easy to wick up and work with. I was able to melt the solder and glide the cap leads into the hole without cleaning all the solder from the board. Cleaning all the solder is hard because some of the solder is still hard and doesn't wick well but when mixed you can wick some and heat the rest to allow the cap leads to go throw the hole.
9 19 07
ince modifying the D1 with Black Gates, and the settling/forming of these caps (I used some caps that had already been in a circuit so the forming of these Black Gates thankfully had already pretty much been done) the amp has taken on a very high end musical sound that I can not believe. I am glad that it is as big as it is so that I have room for the Black Gates and that there is room to change opamps and that it has a design that appears to be very good or the sound would not be at the level it is no matter what I do.
Edit: The D1 has taken on a nice 3D presentation with very good spatial information and transparency.
Posted by Hiflight on 9 19 2007
"OPA2111: Very wide and expansive soundstage, very dimensional.
AD8066: Strong bass, good mids, good soundstage depth.
ADA4841-2: Well balanced throughout the spectrum, sweet highs.
They all work very well with both buffers, just a matter of individual taste. The differences are relatively small, with subtle tonal and soundstage variations. The 8397 is slightly more assertive, the 4562 somewhat more intimate.
These should not be considered as the only opamps that sound good in the D1. They are simply my personal ranking. There are many others I have tried that also sound very good.
For those interested in experimenting with different opamps other than those listed above, I would encourage ordering a modest assortment of opamps directly from a distributor and determining ones own individual preferences.
It is very difficult to try to express verbally the subtle differences in SQ between several different opamps. What I hear and describe may be totally different than what someone else perceives.
I can positively state that the improvements in both the DAC and amp sections of the D1 after modifications from stock are very apparent, even to the casual listener; furthermore, these improvements are apparent regardless of which phones I am using.
I should point out that as one improves the sonic quality and accuracy of any amp, it becomes less tolerant of poor source material or components!""
***Optical cables from Sys Concept
On the optical cables my measurements are just the cable but not the connector ends, which of course also add length. With the shortest I mention there is just enough length for a U and about 2cm from tip to tip on the U. this would allow for a iRiver or like device sitting on the D1. If you get it in toslink to toslink and get two of the right angle adapters, which work very well, you can have a short U not projecting out but lying along side of the ends of the D1 and iRiver. Or you could also get a mini to toslink (I got both) in the shorter length and have the U extending on out from the back of the units. I wish now I had gotten a tos to tos and ppurchased two 90 degree adapters. I also go the longer length in both toslink and mini to allow for a little more separation, though not much, or a different component with a toslink or mini out to the mini in of the D1. There, how is that. :^)
The shortest length, end to end as specified by Sys. Concept is 9.5cm and the longer one I got is 13.5 from one end to the other end of the entire optical cable including ends.
***A great extra battery for many uses for the D1 and other portable electronics is the Tekkeon MP3450, which is an all contained battery and charging unit. I bought mine at Costwonder on Ebay.
Posted by HiFlight on 10 5 2007:
Info for Opamp Rollers!
There have been considerable posts recently regarding which is the "best" choice of opamp, as well as discussion regarding the possibility of delaying ordering the D1 until iBasso comes out with a "better" or "best" configuration.
That will NEVER happen! It is relatively easy for me to pick 5 or 6 good choices, but even when several of us really "hardcore" rollers get together for a mini-meet, we rarely agree on which sounds "best". My favorite is rarely the same as the others in attendance, and it often results in each individual favoring a different opamp.
It is even more difficult for iBasso to arrive at a configuration that will please everyone, as they have issues such as cost, availability and battery life to consider. They may choose to develop something entirely different, such as an amp that has an exterior power supply, or even a different circuit configuration. They will not, I can say with certainty, find one opamp that will be a magic bullet for everyone!.
Many feel that using different opamps in amplifier will result in coloration of the sound. Technically speaking, perhaps this is correct, but all music is colored to some degree or another by room acoustics, hall size, speakers or headphone characteristics, and even by our own personal physiology among other things.
Everyone has their individual preference for sound quality, such as "punchy" bass, lots of "presence", smoother highs, etc, etc, etc.
These are all simply different shades of coloration, and no one opamp will satisfy everyone, just as no specific brand of source, amp or phones can be called the "best".
I would suggest simply trying several different opamps and see how they sound. It is easy, relatively inexpensive, and one will undoubtedly find a configuration that sounds the BEST to you!
I have tried to suggest, based on many trials and combinations of opamps and benchmarked for sound quality against one of my high-end tube amps, to post a selection of opamps that will perhaps eliminate some trial and error in the selection process. I always consider battery life and reliability along with sound quality, as these are every bit as important as other factors when choosing a possible replacement for the factory defaults.
Please don't ask what is the BEST, because there is not an answer that will suit the tastes of all listeners!!!
Any of the opamps mentioned in previous posts as good swaps are fine choices, but in the end, the "best" choice is what YOU like!!!!
Posted by HiFlight on 10 6 2007 on opamps:
********My personal favorite D1 configuration
Either the ADA4841-2 or LTC6241HV as LR with LMH6643 as buffers.
All 3 are only available in the SOIC configuration and need to be soldered onto adapters.
Posted by HiFlight on 10 7 2007
*********Low current draw=long battery life
I have found a very nice-sounding opamp combination that draws only 14ma total for all 5 opamps, (1DAC, 1L/R and 2 buffers) compared to the stock configuration that draws approx. 40 ma. In comparison, the OPA2111/LM4562/AD8656, while a fine-sounding combination, draws about 43ma.
This should result in significantly longer battery life even when using the full DAC/Amplifier combination.
Tonal balance, soundstage and detail are very good, with a clean, open sound.
The following are the opamps I used in this configuration:
L/R: ADA4841-2
Buffers: LMH6643
DAC: LT6234
One can substitue the LT6234 or the LTC6241HV for the ADA4841 with little audible difference. Also the ADA4841 works quite well in the DAC socket in place of the LT6234.
There are slight differences in the sound when changing LR opamps, but please do not ask me which is best. They are very close, and the choice will largely be determined by the choice of music, headphones, and personal preference.
I do find that with these combinations the sound quality is VERY close when switching the same source (iRiver H120) between the D1 Aux input and the Optical input, which tells me that the quality of the amplifier section is now equal to the quality of the DAC.
If using the D1 primarily by battery power rather than with an adapter, one might wish to try some of these low-current draw opamps.
10 10 07 Opamp Update by HiFlight
HiFlight's latest...
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by HiFlight 10 12 2007
In the ongoing but elusive search for musical perfection the rolling continues!
The following configuration is probably one of my personal favorites:
LTC6241HV L/R
LMH6643 Buffers
LMH6643 DAC
All 3 are SOIC and need adapters.
For those who might be interested in additional details, please PM or Email me.
Opamp Datasheets
For those opamp rollers who might be interested in researching some of the technical specifications of many of the opamps we have mentioned on this and other threads, I am reposting below a list of opamp datasheets I originally posted as a "Sticky" on the Xin forum.
*******************************
http://hjem.get2net.dk/tkhifi/data-blade/ad744.pdf AD744
http://www.analog.com/UploadedFiles/...eets/AD746.pdf AgnD746 (dual)
http://ist-socrates.berkeley.edu/~ph...iles/ad743.pdf AD743
http://www.analog.com/UploadedFiles/...eets/AD746.pdf AD746
http://www.analog.com/UploadedFiles/...751AD797_d.pdf AD797
http://www.onsemi.com/pub/Collateral/NE5534-D.PDF NE5534
http://focus.ti.com/lit/ds/symlink/opa228.pdf OPA227/228
http://www.uib.es/depart/dfs/GTE/sta...ETT/OPA604.pdf OPA604
http://www.ociw.edu/instrumentation/...rts/OPA627.pdf OPA627
http://www.ociw.edu/instrumentation/ccd/parts/AD829.pdf AD 829
Analog Devices AD843 - 34 MHz, CBFET Fast Settling Op Amp AD843
http://www.analog.com/UploadedFiles/...eets/AD823.pdf AD823
http://ezphysics.nchu.edu.tw/prophys...eet/lt1028.pdf LT1028
http://www.linear.com/pc/downloadDoc...26,P1293,D1612 LT1115
http://www.acoustica.org.uk/t/naim/d...mps/ad8610.pdf AD8610
http://www.analog.com/UploadedFiles/...156OP275_c.pdf op275 (dual)
http://tinyurl.com/avy7k OP285 (dual)
http://www.analog.com/UploadedFiles/...22AD8397_0.pdf AD 8397 (dual)
http://focus.ti.com/lit/ds/symlink/opa2134.pdf OPA134, 2134 (dual)
http://www-micrel.deis.unibo.it/DATA_SHEETS/OPA128.pdf OPA128
http://www.fulcrum.ru/Read/CDROMs/TI...cs/sbos140.pdf OPA2111 (dual)
http://www.ociw.edu/instrumentation/...rts/LT1365.pdf LT 1364 (dual)
http://www.schuro.de/Daten/Burr%20Brown/OPA2107.PDF OPA2107 (dual)
http://www.analog.com/UploadedFiles/...D8065_8066.pdf AD8066 (dual)
http://www.soundlabsgroup.com.au/mm5..._datasheet.pdf AD825
http://tinyurl.com/ya9qbr AD822
http://www.analog.com/UploadedFiles/...1-1_4841-2.pdf ADA4841-2 (dual)
http://focus.ti.com/lit/ds/symlink/ths4032.pdf THS 4032 (dual)
http://www.analog.com/UploadedFiles/...ets/AD8599.pdf AD8599 (dual)
http://tinyurl.com/25le6o LT6234 (dual)
http://cache.national.com/ds/LM/LM4562.pdf LM4562 (dual)
http://cache.national.com/ds/LM/LME49720.pdf LME49720 (dual)
http://tinyurl.com/kpyrz AD8566 (dual)
http://tinyurl.com/j6kz8 AD8616 (6v !) (dual)
http://tinyurl.com/ehwcs AD8656 (6v !) Solid Tube (dual)
http://www.tranzistoare.ro/datasheets2/50/502419_1.pdf LTC6241HV Solid Tube WV (12v) (dual)
http://tinyurl.com/ykfqh5 EL8201 (Buffer) (6v !)
http://tinyurl.com/yh33gc AD8531 (Buffer)
http://tinyurl.com/yelsjy TLV4111 (Buffer)
http://focus.ti.com/lit/ds/symlink/buf634.pdf BUF634 (Buffer)
http://cache.national.com/ds/LM/LMH6642.pdf LMH6643 (Buffer) (dual)
http://www.asmeltec.de/dl0az/datasheets/HA5002.pdf HA5002 (Buffer)
http://eshop.engineering.uiowa.edu/N...3/DS012336.pdf LM6171 Buffer
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10 27 2007 Post from Ron Hiflight
Try this one!
Not content to leave well-enough alone, I decided to make some adapters using the Browndog single to dual DIP adapter to mount some of my opamps that I had used in my Xin amps and see if my all-time favorite for my SM-IV, the AD797, sounded as good in my D1.
I bypassed the buffer sockets with plug-in sockets that jumpered the input/outputs of both buffers, rendering them a straight wire. As the AD797 has a pretty good current output and extremely low noise as well as nearly perfect square-wave response, I figured that buffers would only downgrade the sound. I found this to be the case in the D1 as well as in the Xin amp.
It is a very tight fit when putting in the 2-1 adapter for L&R, and requires bending a couple of caps to the side a small amount in order to seat the Browndog.
The resulting sound was certainly worth the effort, as it is even more spectacular in the D1 than in the SM-IV, due to the fact that the D1 seems to be very stable, even with fast opamps. At any rate, the sound is very full and warm, with deep fundemental bass that one can almost feel, especially when running an optical input. Trebles are clean and crisp with no excessive brightness or sibilence. Soundstage is very natural, with instrument placement very solid and stable.
I would say that the SQ is very similar to that experienced with high-end tube amps
Due to space limitations on the 2-1 adapter, it is not possible to use 2 browndog mounted SOIC opamps, however most of the ones I used successfully in the Xin were of DIP configuration.
Rather than solder the opamps into the adapter, I soldered 2 standoff sockets onto the adapter, thereby making it quick and easy to change opamps while leaving the adapter in place.
If one really wanted to use browndog mounted SOIC single-channel opamps, the sockets could be soldered to the adapter at a slight angle, providing a little more room, however I doube that I will be trying too many other opamps, as I really like the sound of the bypassed 797s.
To summarize, if interested in trying this combo, one needs a 2-1 single to dual Browndog adapter (DIP), 4 sockets, 4 jumpers, and 2 AD797 DIP opamps. Soldering the sockets onto the adapter requires soldering 8 small pins that in are close proximity to each other. Solder bridges are NOT good! Once the sockets are done, the rest is quick and easy.
**** Quote from HiFlight
"I like more power and higher slew rate for buffers. AD8397 and LMH6643 are hard to beat for buffers if you need to drive low-impedance phones.
For higher impedances and especially if they are pretty efficient phones, the LME49720 is a very nice sounding opamp buffer. They have limited output power though."
Then in a sperate post, or PM (I forget)
"LMH 6643 is [another] choice for the buffer sockets, making the choice for buffer:
AD8397: (bold, works well for rock, most output power)
LMH6643: Smooth, warm, nice with bright phones)
LME49720: Nice frequency balance, superb soundstage. Great choice for instrumental and complex harmonies."
Ron Kerlin
From a post by Dual:
Heres some DIY dummy opamps I just cooked up to bypass the buffers for the AD797.
They are very simple to make all you need to do is short pins 1-3 and 5-7 on the socket with some thin metal wire.
You don't even need to solder them in if the wire is a tight fit but do so anyway just to be safe.
I perfer the AD797 with bypass buffers than with 2x AD8397.
12 24 07 post by musicmaker:
After several permutations & combinations of LR, buffer, DAC opamps, I have found a combo that sounds the best to my ears.
LR: AD797, buffers: bypassed & DAC: LT6241
12 25 07 by musicmaker:
Here are the opamps I've tried:
OPA2111, AD797, LMH6643, LM4562, LT1364, LT6241, LT6234, AD8656, AD8397, AD8599, LME4972 & stock of course
1 9 2008 Pete7
I did do a little more comparing with the D1 amp section and the P2. This time in the D1 I used THS4032 with the LMH6643's (which come stock now) as buffers, and in the P2 I used THS4032 in L/R and LT4236 in 3/4. The P2 definitely sounds like the better amp, although the difference isn't all that noticeable unless you really look for it. With the P2 the sound is a little more textured and detailed, and the soundstage is closer, music a little more impactful. Both sound terrific, and if I had to give a percentage difference between the two it would be like 3-4%. I think I'm giving AD797's a break in both units as now I want a more balanced sound. The THS4032's seem to have a little more in the highs. The AD797's with the buffers bypassed sounded pretty decent in the D1, but with my ES2's it sounded a little dark.
1 24 2009 HeadphoneAddict
If the new ones come with 6234 in DAC, LT1364 in L/R and LMH6643 in buffers, there isn't a huge reason to change anything.
Mine had AD8616 in DAC stock, and the AD8656 was much better, while the LT6234 was an additional upgrade above that.
Mine had AD823 stock, and I tried the OPA2111 withAD8397 in the buffers and it was a noticeable upgrade, but then I tried the AD797 in L/R with those AD8397 in buffers, and the sound is tremendous.
You should take out the LMH6643 from buffers and try the AD8397 with the AD797 - you get great smooth detailed highs, warm forward mids, and tight quick strong bass. With the opamps I have in it now it sounds very much like my P2 did, and everyone agrees the P2 is a great sounding amp.
1 29 2008 Posted by HiFlight
Winner and still champion!
After all the months spent rolling opamps and various cap mods to my D1, I finally went back to an opamp I had used very successfully with my Xin amps..the AD743.
This was my favorite opamp when most of the amps were designed for single-channel opamps. I had almost forgotten about it.
The AD743 is not well-known in audio circles, as it is primarily designed for sonar applications. Nontheless, it is smooth, accurate, and has great low-end depth and impact; it also renders all types of music with a very lifelike and realistic soundstage.
I am using the 743 with the LMH6655 buffers. I feel they are a bit more accurate than is the LMH6643.
My top 3 opamp choices for the D1 are: AD743 (single), AD797 (single), THS4032 (dual)
The 797 has more bass, the 4032 has more detail and transient response, but the 743 is just overall "right" to me.
1 31 2008 Haymaker18
To take a page from Hiflight, the AD743 and LMH6655 just "sounds right"
Unlike some of the others, I can't really describe a particular strength of it because it doesn't sound colored or unbalanced to me...just natural and right.
