Here's an interesting article relevant to this thread I just came across:

http://www.anandtech.com/guides/showdoc.aspx?i=3467

Here is a link to the custom power supply referenced in this article:

http://sjostromaudio.com/joomla/index.php?option=com_content&task=view&id=57&Itemid=27

What about a linear power supply like this one?

http://www.aplab.com/pcc/ps03-a.htm

Nick, thanks so much for your post!  This was exactly the kind of information I was looking for....someone who had actually run this type of experiment.  I use a Lynx AES16 PCI card that outputs AES/EBU to my DAC and want to try what you've done.  Can you provide a link to the site where you bought your power supplies?  How loud are the fans and are there any power supply alternatives which run silent?  Also, some pictures would be greatly appreciated when you have time!

Thanks again.  Greatly appreciated. 

Mani, since my post I spoke to a friend who owns both the BADA and the Pacific Microsonics Model 2.  He told me the Model 2 is more resolving to his ears and regards it as being superior. 

The Berkeley guys decline to confirm what DAC they use....but I'm pretty sure it does use the Delta-Sigma. 

This comes right out of the BADA manual: "Filter 2 is the same filter used in the Pacific Microsonics PMD-100 and PMD-200 HDCD decoder IC’s."  And they were clear in saying they regard Filter 1 as being superior to Filter 2 and that neither the Model 1 or 2 had the computing power to run it.

Have you had any experience with the Merging Pyramix Mykerinos software/hardware offering? 

Telstar, yep, it is certainly much more expensive than other sound cards.  Plus, it appears it will only be at its best if you use the Paramix software. 

Dan, what a coincidence.  Tim Marutani called me within an hour of my post and we spoke for about an hour about the trial you guys did.  I have very deep respect for Tim.

What XXHE settings did you use for the test?  I presume you used unattended playback, engine 3, etc.?  Did you use Quad Arc Prediction mode as well as no upsampling?  Thanks for sharing your experience.

Dan, one other question.  Was the system you heard the Mykerinos in running Windows 7 or Vista?  I went onto the Merging website and it's unclear to me if the Mykerinos drivers support Windows 7 32 bit or 64 bit yet.

 

Hi Dan.  Interesting.  Was that Mani's system you heard it in?  I know he has a Model 2.  I use the AES16 and a Berkeley Alpha DAC which is the successor, next generation DAC from the guys who built the Model 2.  I am intriqued.  So let me understand better.  You were able to do an A/B comparison of your AES16 card versus the Mykerinos card where everything else remained constant...i.e. same DAC, amplifiers, speakers, etc.?

In what ways was the Mykerinos better than the AES16?

Thanks!

I spoke with the guys at Berkeley (formerly Pacific Microsonics) and did some more experimentation with my Berkeley Alpha DAC (BADA). 

Mani, as I mentioned before the BADA has 4 filters (actually 8 as there are 16 and 24 bit versions of each of the 4 filters).  Filter 2 is the same filter as used in your Model 2.  Filter 1 is a more sophisticated filter which required computing power that was not available when your Model 2 was designed/manufactured.  AFAIK, the BADA will not upsample an incoming 176 signal, but will upsample incoming 44.1, 88.2 streams.

Coming out of XXHE with no upsampling (NOS) and no interpolation/filter and using filter 1 I get amazing SQ.  Basically, filter 1 is a form of QAP - i.e. it is an upsampling and interpolation algorithm.

However, while the differences are subtle, I continue to prefer using QAP into the BADA - using either filter 1 or 2 gets me excellent results.  To my ears, with QAP the sound is more "filled in", there is more detail and three dimensionality and that bit of glare at the high frequencies is reduced/eliminated.  BTW, to my ears, the bottom end is more resolute with QAP which some might hear as less powerful.  I think this is because with QAP there is a reduction in time smearing which is what makes the bass sound louder (like a loudness control).

Based on my input and their other customers, they are going to set up XXHE on Win7 and experiment with it.   They told me that while upsamping is obviously optional, every DAC has to have some form of digital filter.  Peter, I got the impression that your DAC was going to be devoid of any digital filter?  Is that right?  They asked me what type of minimal digital filter would you want to see used with QAP?

I ran a test using an SPL meter.  Going QAP into my DAC increases sound pressure by 5-6 db versus going in with no upsampling.  This occurs independent of whatever filter setting I use on the DAC.

No worries as the Aussies say....    Not your fault...you were just another victim of Murphy's Law....anything that can go wrong, will go wrong, and usually when least expected....   

Hopefully StarTech tech support can fix the issue.  Otherwise you should demand a full refund.

Interesting....perhaps it is just perception.  I'll get my trusty portable frequency analyzer and SPL meter out and run a trial. 

Sorry to hear that!  In your experiment were you using the ExpressCard in a laptop or were you using a desk-top PC?  Dang, I was looking forward to hearing about the power supply experimentation.....   

I notice when turning QAP on that the volume goes up versus having it off.  Why is that?

Mani, do I remember correctly that you have a Pacific Microsonics Model 1 or 2? 

Interesting device and pretty cheap as well.  We'll look forward to hearing how well it works for you.  I've tried coax, toslink and AES/EBU into my Berkeley Alpha DAC and the AES/EBU interface was easily superior.  AES/EBU compared to S/PDIF uses a voltage range of 2-7 volts versus S/PDIF's range of 0.5-1 volts.  Clearly, other variables come into play such as what's on either end of the interface.  Good luck with your experiment.  Trying the I2S output is an interesting idea.