[Newk Yuler]

I have a suggestion for Bifrost and Gungnir owners who have done the gen 2 USB upgrade.  I realize this thread is for the Uber upgrade but there is no thread specific to the USB upgrade and many of you who did the Uber upgrade did the USB upgrade too.  I have a Bifrost Uber I recently upgraded myself but it doesn't have a USB board.
 
I stumbled into something that may provide an improvement on the gen 2 USB performance.  As a disclaimer up front I admit that I don't know 100% for certain this will work on a Schiit gen 2 USB board but I have proven it to myself with similar base components.
 
The gist of it:  Try one of the ADuM4160 USB isolators in line between the computer and the gen 2 USB input on your Schiit DAC.
 
Further information based on my experience:  The ADuM4160 device may not work with the original USB board using the CM6631 receiver chip.  My experience is with an inexpensive Chinese USB to S/PDIF converter (feeding a Bifrost Uber) that uses the CM6631A receiver as is used in the gen 2 USB board.  I looked around tech forums on the web and I found no indication that the ADuM isolator has been used with either the CM6631 or the newer CM6631A.  I assume (ass-u-me) it's because the ADuM may be incompatible with the earlier chip and because of it nobody has tried it with the newer chip.  FWIW, I emailed Jason at Schiit about my discovery and he told me they are aware of the effects and he was obligated to not discuss details.  The ADuM isolator apparently does not work with XMOS USB inputs.
 
I purchased a couple of cheap async USB-S/PDIF converters using the latest revisions of the XMOS and C-Media receivers because I wanted to see how inexpensive cutting edge asynchronous tech held up against my Off-Ramp 3 that uses Steve Nugent's final generation design of adaptive USB (before moving to async USB).  Neither of the cheap converters performed as well as the older and much more expensive Off-Ramp.  The cheap converters both sounded slightly veiled and sterile but they did exhibit half decent stereo reproduction to some degree.
 
I read a recent article at CA by a guy in Poland who compared most of the current high end USB to S/PDIF converters.  In the article the author spent time tracing the circuit in an absolute top end Berkley converter.  In the back end of their USB circuit there is (what he believes is) an ADuM isolator.  It can't be the ADuM4160 because it's designed for USB protocol.  The chip in the Berkley is isolating whatever information has been decoded from the USB circuit.  All that aside, it served to remind me that I had one of the ADuM4160 isolators I got a few years ago to try with the Off-Ramp.  Ruined the performance and the ADuM got stored.
 
I dug out the ADuM and put it in line between my Windows OS music server and the cheap CM6631A converter.  Immediately there was a heavy veil removed and the stereo image became MUCH more holographic on the Bifrost Uber.  Significantly better than with the Off-Ramp, but that's not to say the Off-Ramp isn't more precise with its characteristics.  I'm simply saying the combination of the ADuM isolator on the CM6631A converter made a very significant difference in a perceived bloom of the image over the converter alone and apparently over the older Off-Ramp 3.
 
The ADuM allowed the CM6631A driver (Schiit's driver package) to load without a hiccup.  There is a drawback in the ADuM is limited to a throughput equivalent of 24 bit 96 kHz audio.  Also, my experience includes the lossy S/PDIF part of the circuit that's almost certain to be measurably worse than using the ADuM on Schiit's well designed USB input.  In other words there's a potential for your experience to be better than mine.  Makes me want to get a gen 2 board.
 
Trying this will cost you $30 to $50 USD for the basic ADuM4160 USB isolator plus a decent little 12 VDC wall wart.  You'll also need another short USB cable comparable to the proper quality cable you're using with the Schiit DAC.  I take no responsibility for you trying it.  As I said, I'm not completely certain it will work on the Schiit gen 2 USB board but I completely believe it should work and it may provide a very significant increase in the quality of stereo image coming from your Schiit DAC.
 
-------------------------
EDIT/UPDATE, August 21.
 
I've done a lot more searching on the web and everything I've seen says the ADuM and the USB-S/PDIF converter combination I'm using should not be working.  I've seen at least a couple of testimonies that state the ADuM does not work with the earlier version of the C-Media chip.  There is apparently no one else in the world that's tried the ADuM USB isolator with the newer version of the C-Media chip, except maybe the techs at Schiit.  I bit the bullet and bought the gen 2 USB board today.  I'll try it with the ADuM and update the post again later.
 
It's difficult to express just what an amazing upgrade these parts have had in my audiophile music server system.  It's clear that the voodoo combo I mention in this post has trounced the Off-Ramp 3.  If the gen 2 USB board doesn't work with the ADuM isolator and the gen 2 USB is inferior without it, it will prove the value of the voodoo combo ADuM/USB converter.

 

[NightFlight]

Quote:

I thought I'd post this here. I just got a Bifrost uber. I am replacing this with a emotiva xda-1. I hook up the bifrost to my pc via toslink and there was no sound, using jriver. I then took it out of my pc and connected it to my cd player and that worked. Then i remember i have foobar on my pc which i dont use because i like jriver better. I open foobar and it works with that. So i start messing with the settings of jriver and i think putting the sample rate to "no change" did it. 
 
Now the third day with the bifrost. I start hearing clipping sounds then the sound would go off. Then I had to play around the setting and it would starting having sound again. This happened with foobar as well. This dac is very sensitive to my pc. Also sound quality wise it isnt better than the xda-1. The clipping sound is annoying as hell. So far this hasnt been a good experience.

 
Well, get this. Every Mac I've tried with the Bifrost to my ear a) sounded confined and poor. b) would cut out.  I tossed in a well known CD transport via toslink and the thing opened up pretty well. The Uber USB card I believe to be more tolerant of USB jitter, since my original was replaced at the time the Uber came out for that reason. It was fine with my PC+Foobar, but any Mac wouldn't even play properly. I do mean _any_ mac. I have access to 1000's. IMHO, their not the best choice for audio reproduction.
 
Cracks me up to see all those Mac laptops in pictures of meets. I tried Amarra. She helped a lot, but still suffered by comparison to a real CD transport like the  say a Sony DVP S7000. Nice clock I'm told is the trick. You can still find them cheap at hawk shops.
 
My PC just uses a random Asus board. Luck would have it works very well for me over my $5 toslink cable. My modded XDA-2 seems to prefer it in fact. Windows 7 SP1 hates my USB on the XDA-2. It was fine prior to the update.

 

[gefski]

About half the posts I read on this thread are useless becuase they don't correctly state what product or combination of products is being described. Schiit has offered two Bifrost upgrades -- Uber Analog and USB Gen 2.

 

[internethandle]

Quote:

I have a suggestion for Bifrost and Gungnir owners who have done the gen 2 USB upgrade.  I realize this thread is for the Uber upgrade but there is no thread specific to the USB upgrade and many of you who did the Uber upgrade did the USB upgrade too.  I have a Bifrost Uber I recently upgraded myself but it doesn't have a USB board.
 
I stumbled into something that may provide an improvement on the gen 2 USB performance.  As a disclaimer up front I admit that I don't know 100% for certain this will work on a Schiit gen 2 USB board but I have proven it to myself with similar base components.
 
The gist of it:  Try one of the ADuM4160 USB isolators in line between the computer and the gen 2 USB input on your Schiit DAC.
 
Further information based on my experience:  The ADuM4160 device may not work with the original USB board using the CM6631 receiver chip.  My experience is with an inexpensive Chinese USB to S/PDIF converter (feeding a Bifrost Uber) that uses the CM6631A receiver as is used in the gen 2 USB board.  I looked around tech forums on the web and I found no indication that the ADuM isolator has been used with either the CM6631 or the newer CM6631A.  I assume (ass-u-me) it's because the ADuM may be incompatible with the earlier chip and because of it nobody has tried it with the newer chip.  FWIW, I emailed Jason at Schiit about my discovery and he told me they are aware of the effects and he was obligated to not discuss details.  The ADuM isolator apparently does not work with XMOS USB inputs.
 
I purchased a couple of cheap async USB-S/PDIF converters using the latest revisions of the XMOS and C-Media receivers because I wanted to see how inexpensive cutting edge asynchronous tech held up against my Off-Ramp 3 that uses Steve Nugent's final generation design of adaptive USB (before moving to async USB).  Neither of the cheap converters performed as well as the older and much more expensive Off-Ramp.  The cheap converters both sounded slightly veiled and sterile but they did exhibit half decent stereo reproduction to some degree.
 
I read a recent article at CA by a guy in Poland who compared most of the current high end USB to S/PDIF converters.  In the article the author spent time tracing the circuit in an absolute top end Berkley converter.  In the back end of their USB circuit there is (what he believes is) an ADuM isolator.  It can't be the ADuM4160 because it's designed for USB protocol.  The chip in the Berkley is isolating whatever information has been decoded from the USB circuit.  All that aside, it served to remind me that I had one of the ADuM4160 isolators I got a few years ago to try with the Off-Ramp.  Ruined the performance and the ADuM got stored.
 
I dug out the ADuM and put it in line between my Windows OS music server and the cheap CM6631A converter.  Immediately there was a heavy veil removed and the stereo image became MUCH more holographic on the Bifrost Uber.  Significantly better than with the Off-Ramp, but that's not to say the Off-Ramp isn't more precise with its characteristics.  I'm simply saying the combination of the ADuM isolator on the CM6631A converter made a very significant difference in a perceived bloom of the image over the converter alone and apparently over the older Off-Ramp 3.
 
The ADuM allowed the CM6631A driver (Schiit's driver package) to load without a hiccup.  There is a drawback in the ADuM is limited to a throughput equivalent of 24 bit 96 kHz audio.  Also, my experience includes the lossy S/PDIF part of the circuit that's almost certain to be measurably worse than using the ADuM on Schiit's well designed USB input.  In other words there's a potential for your experience to be better than mine.  Makes me want to get a gen 2 board.
 
Trying this will cost you $30 to $50 USD for the basic ADuM4160 USB isolator plus a decent little 12 VDC wall wart.  You'll also need another short USB cable comparable to the proper quality cable you're using with the Schiit DAC.  I take no responsibility for you trying it.  As I said, I'm not completely certain it will work on the Schiit gen 2 USB board but I completely believe it should work and it may provide a very significant increase in the quality of stereo image coming from your Schiit DAC.
 
-------------------------
EDIT/UPDATE, August 21.
 
I've done a lot more searching on the web and everything I've seen says the ADuM and the USB-S/PDIF converter combination I'm using should not be working.  I've seen at least a couple of testimonies that state the ADuM does not work with the earlier version of the C-Media chip.  There is apparently no one else in the world that's tried the ADuM USB isolator with the newer version of the C-Media chip, except maybe the techs at Schiit.  I bit the bullet and bought the gen 2 USB board today.  I'll try it with the ADuM and update the post again later.
 
It's difficult to express just what an amazing upgrade these parts have had in my audiophile music server system.  It's clear that the voodoo combo I mention in this post has trounced the Off-Ramp 3.  If the gen 2 USB board doesn't work with the ADuM isolator and the gen 2 USB is inferior without it, it will prove the value of the voodoo combo ADuM/USB converter.

 
Very interesting. I have a Olimex ADuM4160 isolator that I still used between another, older adaptive USB 1.1 DAC (Keces DA-151) to good result, but it's never played well, as you mentioned, with my Bifrost's first gen USB board. Either no sound or a loud screeching. I have the Uber Analog board installed, but have waited on the USB gen 2 board, partially because there's such a dearth or information about it in terms of user experience and SQ improvement relative to the Uber Analog. Previously, as well, I could find no confirmation on Head-Fi or elsewhere that the CMedia chip used on the USB Gen 2 board was different at all - people seem to have been asserting that it's the exact same USB receiver chip, just with, apparently, a jumper skipped or some such by Schiit on the chip (as implied by the green wire soldered on the edge of the chip in USB gen 2 boards). Jason and co. have also remained mute about the changes schematically or otherwise on the USB Gen 2 board. Your post makes it clear that this is not the case, and that there is, indeed, a new chip (or, rather, a new revision to the old chip) on the USB gen 2 board. Anyway, there are already some indications by others that SQ was improved by the USB gen 2 board over the old board WITHOUT the ADuM isolator - please let us know how it is with! 

 

[Newk Yuler]

Quote:

 
Very interesting. I have a Olimex ADuM4160 isolator that I still used between another, older adaptive USB 1.1 DAC (Keces DA-151) to good result, but it's never played well, as you mentioned, with my Bifrost's first gen USB board. Either no sound or a loud screeching. I have the Uber Analog board installed, but have waited on the USB gen 2 board, partially because there's such a dearth or information about it in terms of user experience and SQ improvement relative to the Uber Analog. Previously, as well, I could find no confirmation on Head-Fi or elsewhere that the CMedia chip used on the USB Gen 2 board was different at all - people seem to have been asserting that it's the exact same USB receiver chip, just with, apparently, a jumper skipped or some such by Schiit on the chip (as implied by the green wire soldered on the edge of the chip in USB gen 2 boards). Jason and co. have also remained mute about the changes schematically or otherwise on the USB Gen 2 board. Your post makes it clear that this is not the case, and that there is, indeed, a new chip (or, rather, a new revision to the old chip) on the USB gen 2 board. Anyway, there are already some indications by others that SQ was improved by the USB gen 2 board over the old board WITHOUT the ADuM isolator - please let us know how it is with! 

 
There are performance improvements in the CM6631A over the older chip that should allow better sound quality in the Schiit DACs.  Providing a better quality signal out of the USB section for the digital and analog parts to work with.  I believe Jason has mentioned it and I've read about it elsewhere.  That's why doing both the Uber and gen 2 USB upgrades is important for getting the best out of a stock Bifrost.
 
I should have mentioned earlier that my ADuM board is the old DIY Paradise Ultravox.  There are differences with it over others such as the Circuits@Home USB isolator.  For one, the Ultravox is hardwired at USB 1 full speed (12Mbit/s) on both sides of the isolator chip.  It passed a test for 24 bit 96 kHz throughput.  Another is the 5v downstream power (supplied from the 12v wall wart) is passed by a linear regulator and has the potential of being cleaner than those that use a switch mode regulator (like the Circuits@Home).  The USB converter in the voodoo combo is powered from the USB connection and may be performing better because of cleaner power coming from the Ultravox ADuM board.  Another thing I want everyone to know is the cheaper Chinese made Circuits@Home ADuM USB isolator on eBay is confirmed a stolen design clone and its quality may not measure up to the one sold directly from Circuits@Home.  As a matter of good ethics I support the work of the guy that designed and backs the board.  I've read some about the Olimex isolator.  A lot of people used them.  Someone else is going to have to prove if either of those USB isolators work with the gen 2 USB.  If I get another ADuM isolator as a backup it will be another Ultravox (if they're still available) because of its proven compatibility and the VERY significant sound quality improvements it creates with the CM6631A based USB converter I have (and hopefully in a few days with the Bifrost).  I welcome someone else telling me I'm wrong and providing better logic.
 
BTW, the USB Converter I've been talking about is this:
 
http://diyhifishop.com/cm6631a-24bit192khz-usb-to-coaxial-optical-fiber-by-weiliang-p-72.html
 
Or this without the case:
 
http://diyhifishop.com/new-version-cm6631a-24bit192khz-usb-to-coaxial-and-optical-fibe-p-71.html
 
The vendor links are an alternate.  I bought the encased version from Hifiwow in China and it was a bad experience.  I won't go into detail but I will say it took 2 and a half months to arrive and communication with them was horrible.  I was very surprised to receive the package (at all).
 
I chose it as a CM6631A part because of this (link below) and his discovery concerning Mac compatibility (that a friend needs).  I don't agree with much of what he says about downplaying jitter and sound quality.  There are many high grade audiophile equipment manufacturers and experienced users who will disagree with his opinion.  It's also very apparent that the converter alone isn't the magnificent audio cure-all he thinks it is.
 
http://archimago.blogspot.com/2013/03/measurements-adaptive-aune-x1.html
 
As I understand it right now (I may be wrong) the ADuM4160 doesn't work with many of the newer asynchronous USB receivers because they use full USB 2 spec operations to handshake with the USB host.  The ADuM4160 is USB 2 compliant as it connects with a USB 2 host but it won't pass a full USB 2 handshake from the peripheral.  That means the cheap USB-S/PDIF converter with a CM6631A receiver apparently has what's needed to handshake with the host at the USB 1 spec.  It remains to be proven if it's a characteristic of the CM6631A receiver or if it's unique to something else in the USB converter.  If it works similarly with the Schiit gen 2 USB we'll know the rest of the story.  Again I welcome anyone that knows better to tell me I'm wrong and provide better information.
 
The gen 2 USB card shipped today and should be here Saturday or Monday.  If it turns out the Ultravox ADuM works with the gen 2 USB I'll probably move all this information to its own thread.

 

[Newk Yuler]

The DIY Paradise Ultravox ADuM4160 works with the Schiit gen 2 USB with issues.  The gen 2 USB alone doesn't have the lush blooming sound quality.  This is observed in my audiophile music server system and YMMV probably depending on how much the electrical noise from your host computer is affecting everything.  The cleaner the host, the better the gen 2 USB should sound on its own, but you won't know the difference unless you try the USB isolation.  It could be a small but noticeable to jaw-dropping huge enhancement.
 
The gen 2 USB board I received is v1.35.  There is no green wire jumper on the chip.  Also worth noting is the set of standoffs Schiit sent with the board are about 1/8" short when seated compared to the standoffs on the DAC board.  I had to leave the screws just tight enough to hold the board in place.  Tighter would bend the board.
 
More important background information:  My music server uses Windows XP SP3.  I will try everything again after updating the server with a couple new components and Windows 7 x64.  I expect many improvements but I also expect USB to operate similarly as specified in the standard.  I normally use Foobar2000 as a music player and DirectSound with the kernal mixer bypassed (Steve Nugent's recommended setup for the Off-Ramp 3 in Windows XP).  I use the Foobar bit depth switch and the SoX resampler for changing frequencies, some native high res files, but I normally just play Redbook 16 bit 44.1 kHz.  I realize using Windows XP is ridiculous by now but it has performed well running a music server for over 4 years.  I chose it because of software compatibility issues at the time.
 
The ADuM on the Bifrost gen 2 USB seems to require fiddling and finagling.  Sometimes it needs the USB cable pulled from the computer and reinserted to establish a new handshake with the host.  Sometimes the DAC power needs to be cycled.  Sometimes it needs a reboot.  Sometimes it seems it needs to have the driver uninstalled and reinstalled.  Sometimes some or more of that together.  If the player has been playing well for hours and the connection drops out it may need the treatment.  It's really not a big deal but it's not a cakewalk for someone who knows only plug and play simplicity.  If you know what I'm talking about you should be able to get it to work.  Shut the music player before you make changes and relaunch afterward.  The quality enhancement is worth the trouble.  We're very fortunate it works at some useful level. 
 
When the Schiit DAC is directly connected the driver display in Foobar shows a Schiit DAC is connected.  When the ADuM is in line the display shows "USB 2.0 High Speed True HD Audio".  When the connection fails on launch it asks for a driver with the proper setting missing.  There seems to be a lot more running from the driver package when the gen 2 USB is directly connected to the USB host.  [Edit Aug 29, 2013: I began to wonder if the C-Media driver was used at all with the ADuM in line, so I again tried playing with the C-Media driver package uninstalled and it would not work.  The term "USB 2.0 High Speed True HD Audio" is directly attached to information for the C-Media chip and apparently indicates that part of the driver package is being used.  Stability issues eventually disappeared as I indicate in a later post.]  Windows may show a "can perform faster" warning and show that it sees the ADuM as a USB hub.  That's all okay for the ADuM because it runs at USB 1 full speed and passes data with USB hub timing.
 
It seems important to keep the player's buffer size small as larger settings may cause problems with the data stream when using the ADuM.  I'm not sure of how they interact but I had drop out issues that seemed to lessen as I shrank the buffer size.  500 ms seems to be working well.
 
I listened to the Bifrost gen 2 USB without the ADuM for a few hours today.  It's really very good but it's also very apparent the imaging is not as lush as with the ADuM in line.  I would rate the gen 2 USB without the ADuM to be on a level similar to the Off-Ramp 3.  It's also important to note that the CM6631A USB-S/PDIF converter and Ultravox ADuM "Voodoo Combo" performs at least as well as the gen 2 USB with the Ultravox ADuM and it seems a bit more stable.  This level of performance can be connected to any DAC with a coax S/PDIF input provided it's a proper quality input.  The combo could make a big enhancement on a lot of DACs.  Can make the combo more valuable because of its versatility.  It probably won't perform as well as something like an Audiophilleo or another very expensive USB-S/PDIF converter but there's undoubtedly a tremendous value here.  The combo costs about what a gen 2 board costs, so if you have a gen 1 USB board and you've been thinking about the upgrade, you might consider the combo instead, especially if you don't need to go over 24/96.  Don't forget you'll need a good quality coax S/PDIF cable too.
 
---------------------------------------------------------
 
Update August 26th:  Just checked the current price on a DIY Paradise Ultravox.  USD equivalent with FedEx shipping (mandatory) is a little over $80.  (Ouch.)  The one I have I bought in mid 2010 for a little over $67.  I expect it's still the best ADuM board available for audio.  The Ultravox is designed for audio purposes and other less expensive ADuM boards are designed for electronics projects (like the Circuits@Home).  The Ultravox is suited for the USB-S/PDIF converter I mentioned if you want to power it by the USB connector, but you can also power the converter by an external power source.  It's easier and proven to work well if you just get the Ultravox.
 
Update August 30th:  I've exchanged several emails with the designer-builder of the Ultravox ADuM.  He confirmed the peripheral or down stream side of the ADuM chip is powered by the linear regulator.  The regulator is not special or extra low noise but proper for USB data and he believes it makes his design better for audio purposes.  (The host side of the ADuM chip is powered by the host which is normal to the reference design.)  He also confirmed the ground circuits on both sides of the ADuM are isolated from each other.  I believe the reference design is not similarly isolated.  These are advantages for the Ultravox over other ADuM boards when used for audio.

 

[Newk Yuler]

Today I've been switching between the Ultravox ADuM on the Schiit gen 2 USB and the Ultravox on the CM6631A USB-S/PDIF converter.  The USB-S/PDIF converter is providing a significantly better image bloom.  I expected the opposite for a number of reasons but I'm happy to just go with what works.  The gen 2 USB is still considerably better with the Ultravox than without, so trying an ADuM isolator on your gen 2 USB will likely be at least a significant improvement.  I won't flat out recommend one option over the other because I expect both to perform somewhat differently due to variables in unique systems.  If enough people try something we'll have some weighted feedback on which is the better way to go.  So...?
 
Everything has been much more stable than when I first installed the gen 2 USB board.  Drop outs and failed USB connections are infrequent to non existent vs long hours of play.  It seems reducing the player's buffer size made the big difference.
 
There are a few other important infos to add...
 
I use very good quality silver conductor USB and coax digital cables that I expect made a difference in the results I've experienced.  The coax digital is an Audioquest VDM-5.  The USB is a hand built cable made somewhere in Asia that looked great in specs and was considerably less expensive than similar domestic boutique cables.  I purchased it on a gamble from a reliable, reputable Asian dealer I've used a number of times, so I knew it very likely wasn't some of the fake Chinese BS.
 
For any ADuM device you use there is a benefit to using a short USB gender adapter on the host connection.  It looks like a normal USB cable with the cable gone and the end plugs attached in the middle.  I use one on the host side of the Ultravox.  The benefit is eliminated electrical resistance and increased signal strength for the ADuM.  For example go to search at eBay and copy/paste this in bold: USB 2.0 A male to B Male Adapter -(mini,micro,female,cable).  It's inexpensive and beats spending more on another high grade USB audio cable like the one you're using (or should be) with your Schiit DAC.

 

[amandarae]

Installed Uber upgrade three days ago.  Run the DAC 6 hours a day or slightly more for two days to burn in.
 
It took me 20 minutes and fortunately no mishap.  It is obvious that you have to align the LED's first then secure the board to the inner chassis, not connecting the board to its chassis then align the LED's.  Kudos to the person who posted the procedures here earlier on this thread as it makes doing the upgrade 'pain" free.  Checked all inputs have output sound to make sure that the board was seated properly and I did not accidentally disconnect anything.
 
Yes, there is an improvement in sound.  I cannot put it any "simplier" than that.  A worthwhile upgrade IMHO.
 
Abe

 

[djdonis]

A little OT, but what do you guys do with the replaced USB and analog boards, ship them back, throw away?
I may be interested in gen 1 usb board...

 

[ngyu]

Quote:

A little OT, but what do you guys do with the replaced USB and analog boards, ship them back, throw away?
I may be interested in gen 1 usb board...

I put my old analog board back in the static bag and box that my uber board game in. 

 

[bearFNF]

  I put my old analog board back in the static bag and box that my uber board game in.

Me too...keeping it, "just in case"...

 

[captouch]

  Me too...keeping it, "just in case"...

 
Me three, though the chances of needing it seem nil. . .  

 

[Scallywag]

  Today I've been switching between the Ultravox ADuM on the Schiit gen 2 USB and the Ultravox on the CM6631A USB-S/PDIF converter.  The USB-S/PDIF converter is providing a significantly better image bloom.  I expected the opposite for a number of reasons but I'm happy to just go with what works.  The gen 2 USB is still considerably better with the Ultravox than without, so trying an ADuM isolator on your gen 2 USB will likely be at least a significant improvement.  I won't flat out recommend one option over the other because I expect both to perform somewhat differently due to variables in unique systems.  If enough people try something we'll have some weighted feedback on which is the better way to go.  So...?
 
Everything has been much more stable than when I first installed the gen 2 USB board.  Drop outs and failed USB connections are infrequent to non existent vs long hours of play.  It seems reducing the player's buffer size made the big difference.
 
There are a few other important infos to add...
 
I use very good quality silver conductor USB and coax digital cables that I expect made a difference in the results I've experienced.  The coax digital is an Audioquest VDM-5.  The USB is a hand built cable made somewhere in Asia that looked great in specs and was considerably less expensive than similar domestic boutique cables.  I purchased it on a gamble from a reliable, reputable Asian dealer I've used a number of times, so I knew it very likely wasn't some of the fake Chinese BS.
 
For any ADuM device you use there is a benefit to using a short USB gender adapter on the host connection.  It looks like a normal USB cable with the cable gone and the end plugs attached in the middle.  I use one on the host side of the Ultravox.  The benefit is eliminated electrical resistance and increased signal strength for the ADuM.  For example go to search at eBay and copy/paste this in bold: USB 2.0 A male to B Male Adapter -(mini,micro,female,cable).  It's inexpensive and beats spending more on another high grade USB audio cable like the one you're using (or should be) with your Schiit DAC.

 
This is some really interesting info, thank you. I think I'm going to purchase the isolator board from Circuits@home and try it with the gen 2 USB card. Question... how would you suggest I power the board?? Keeping cost in mind, what kind/quality wall wart might be best?? Is something like a TeraLink linear power supply recommended or might that be overkill or unnesessary in this situation??

 

[blinx]

  A little OT, but what do you guys do with the replaced USB and analog boards, ship them back, throw away?
I may be interested in gen 1 usb board...

 
I kept mine.  And I'm really glad I did because my Uber board stopped working the other day.  I thought my Bifrost was toast, but the old board worked just fine.  Anyway, Schiit is replacing it... But im glad i kept it!

 

[Newk Yuler]

   
This is some really interesting info, thank you. I think I'm going to purchase the isolator board from Circuits@home and try it with the gen 2 USB card. Question... how would you suggest I power the board?? Keeping cost in mind, what kind/quality wall wart might be best?? Is something like a TeraLink linear power supply recommended or might that be overkill or unnesessary in this situation??

 
Thank you for helping me discover this alternative ADuM board.
 
Go to eBay and copy/paste search this in bold: Teralink ADuM4160 USB Isolator board.
 
Or use this link (same seller):
 
http://www.ab-system.hk/index.php?route=product/product&product_id=63
 
That board is made for audio.  If you aren't going to use an Ultravox, this is probably the next best one (IMO).  The jumpers should be set for full speed.
 
Go to Jameco.com and search for 170245.  That's a 12v 1 amp linear regulated wall wart.  I'm not sure about the plug configuration but the rest of it is proper.  I have one of those and a similar 5v version on order that won't ship until the 5v is available again in late October.  There is no option for the supply connectors and they may need modifying.  You might consider putting a ferrite bead close to the connector if there isn't one on it from the manufacturer (RFI filtering for sensitive equipment).
 
Don't forget to get one of the little USB gender adapters I mentioned in my last post (the one you quoted).  Use a good quality USB cable, especially not a cheap utility grade cable.  Preferably one specifically for audio USB.  Go to Amazon and search Pangea USB PCOCC.  Those look like a great value.
 
I have to again say that I take no responsibility for you trying anything I've mentioned.  Computer audio systems usually have unique component synergies and some will undoubtedly behave differently.  Please tell us how it works for you.