Questioning the need for a DAC

My final post, lads. I had some pals over today whose ears I trust, much younger than me,  all with a mortgage-load of audio gear.  It was easy to switch between the Oppo 103 straight-in to the Don Sach's preamp vs. run through the Channel Islands DAC.  I provided the "ear lube" via a local micro-brew pub for the fellas and it was much appreciated by the feedback.  

The conclusion is clear:  On an A/B test, no listener was able to identify the difference in sound with or without the DAC in any consistent fashion.  Often as not, a listener who thought he could perceive a difference, was surprised to learn that the DAC was out in the loop.  I  personally, switching the selector, might have perceived a 5% difference in improvement in the performance of my system with the DAC, but that might be my desire to validate my expenditure for the DAC.  As I continue to perform this comparison after my pals left, I do think there is a maybe 5% improvement in the sound overall, with maybe a bit more clarity, but it is quite subtle.  

So, the conclusion I have reached is that you have a pretty good DAC, or an Oppo upgraded by somebody (mine was upgraded by Stereo Dave and the upgrade was instantly apparent), the sonic value of a DAC in the sub-$1000 price range might be an expense of dubious value.

BTW, I upgraded pair of Mundorf Silver Oils output caps for Jupiter Copper caps in my preamp at the same time I hooked up the CIA DAC so that might have swayed my initial favorable impression the DAC.  The Jupiters caps are a 10% improvement in the sound of the already excellent Don Sachs preamp -- by far the best I have heard in my system.

Cheers, Mark

@williewonka Your findings make perfect sense given the gear you tested, but I am trying to explain something further(i.e. ComputerAudio301 vs. ComputerAudio201which you've already aced!)

"DAC's that use power from their own onboard power supply tend to perform so much better than those that use the power from the computers USB port simply because the power being supplied is so much cleaner that that supplied via the computers USB port" That is true with a PC or mac, but not true with a single purpose low power designed with a better USB output implementation, linux operating system not running a bunch of extra non-audio processes,  and not plugged into a noisy high voltage power supply like a typical computer. For example, a Sonore microRendu or even a $35 Raspberry Pi powered by any decent linear power supply will run fewer processes which could generate noise, and will draw less current which generates noise or attracts EMI noise. What goes via USB to the DAC is far better than what went out of the full function PC or Mac to the Vlink adapter in your test.  

"So my listening test was as follows...
1. the Bifrost DAC was connected via its USB port to my computers USB port, then...
2. I connected the Vlink192 to my computers USB port, but connected it to the Bifrost with via a digital coax.

#2 was clearly superior. " Yes, makes perfect sense!

Was I wrong to conclude that the USB implementation of the V-Link192 is superior to the that of the Bofrost/Gungnir? Yes, wrong conclusion. The proper conclusion is that the V-Link 192 & coax cable allows the DAC to receive better/quieter signal vs. the noisy USB output of your noisy computer.  

"The V-link192 simply converts USB to Coax Digital - and if its USB interface was not superior wouldn't the sound be the same when played through the same DAC?" I think you meant to type that USB is Inferior, not superior? In any case, the issue is more about the computer or other source and less about the DAC. 

That's why aftermarket tweaks like the VLink, uber expensive Berkeley USB-SPDIF adapter, USB cleaners Regen & Intona are popular. That's partially why audio software packages attempt to shut down unnecessary processes running on Mac O/S or Windows O/S. That's why people try all kinds of A/C filtering, power supplies etc on their computers. Because all these things attempt in some way to fight the crap that degrades digital audio signal going to the DAC. If you win that battle (by eliminating the multi-purpose computer!) and pair with DAC you prefer you stand a good chance of winning the war. Cheers,
Spencer

Whitestix I'd be interested to hear which 'pricey' power conditioner you use and of course how you use it.

Spencer...

Was I wrong to conclude that the USB implementation of the V-Link192 is superior to the that of the Bofrost/Gungnir? Yes, wrong conclusion. The proper conclusion is that the V-Link 192 & coax cable allows the DAC to receive better/quieter signal vs. the noisy USB output of your noisy computer.

OK - so after reading your last post - here’s how I see it...

1. the V-link USB interface is processing the very same signal as the Bifrost’s USB interface
2. Somehow, with the V-link in the mix, the Bifrost sounds significantly better
3. From what you have said this is more due to the ability for the V-link to "clean up" the digital signal, as opposed to the quality of the USB interface employed in each component.
4. OK, I can see how that is probably the more significant cause for improvement - but perhaps not the only one :-)

In my defence, I guess my conclusion may have been tainted by the fact that I had previously installed the SCHIIT USB Upgrade board which improved SQ somewhat, so I assumed the V-links’s USB circuit alone was providing the benefit.

FYI, in my system I use a dual lead USB cable - one lead carries only the signal and the other lead carries only the power and they are joined at the end of the cable that plugs into the DAC (or V-link). I have also implemented a separate, very stable power supply in order to eliminate the USB power related issues.

However, the difference the V-link made was also easily noticed even when using a standard USB cable that provides power from the computer.

So when the original poster stated the Gungnir did not provide too much of an improvement I figured I’d post my findings. which I believe still stand ...

• To get the very best out of the Gungnir (or Bifrost), you have to bypass its USB port
  

Regards...

@williewonka That's all very interesting and insightful. I also tried a dual-headed USB from computer to DAC and it did help on its own to decrease noise from the computer to a small degree. Glad to hear you are using an upgraded LPS on the computer.

I am not doubting the benefit you hear from the Vlink, but my conclusion is that "To get the very best out of the Gungnir (or Bifrost), you have to" feed it from a good single purpose source component. Then you don't need to bypass its USB port. I would assert that Vlink would provide little improvement between my microRendu and Gungnir  Bring it over sometime and we can test it out. Cheers,
Spencer