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Questioning the need for a DAC

Friends,
I have a modified Oppo 103 that was a huge step up from my $2K Consonance tube CD player.  I also have a Jolida FX Tube DAC, maybe the II version, which I have had for many years.  I ran the Oppo directly into my system (I have a Don Sachs tube preamp and various amps, tube and SS, and Spatial Audio Hologram M4 Turbo S speakers) and then through the Jolida.  I honestly didn't hear a difference.  Some months later,  I demo'd a Schiit Gungnir and did the same comparison.  I really couldn't discern an audible difference with the Schiit in or out of the system.  I will admit that I sent the Schiit back for a refund after only 30 hours or so of burn-in so maybe 100 hours of burn-in might have lead to a different outcome.  A boatload of audiophiles rave about the sonic improvement with the pricey DAC's in their systems, no question about it.  With my ears, not so much.  

A "cheap and cheerful" audiophile friend of mine, who doesn't listen to much digitally-reproduced music, posed an interesting question.   If one invests in a modern quality CD player (i.e., like the Oppo 103 or 105, which make the Stereophile list of "Class A" products or many others between $1K-$5K), why is there the expectation that one needs a separate DAC to improve the sound of the DAC?   It is not trivial question.  As a matter of fact, I called Oppo while I was auditioning the Schiit DAC, nonplussed, asking why I wasn't hearing some significant improvement with the addition of an external DAC of the caliber of the Gungnir.  In response, the Oppo rep suggested, quite casually, that maybe the internal DAC in the modestly-priced Oppo 103 was quite good.  Indeed, because that is what my 63-year old ears told me.

I'd be keen to hear feedback from others who ponder the same question.   As I age, I am aware of the desire of sellers of many audio products to strike a deal with me that frankly might benefit them more financially than I  benefit sonically.  Cheers, Mark 

  
whitestix
erik_squires
16,051 posts
 
Hi @psickerson

I’m not sure if all have it, but some Schiits have ASRC. Adaptive Sample Rate Conversion. Most of these processes work by throwing away the original data and recreating it. They map the data coming in to a (hopefully) much more jitter free clock and recreate it, but whether going from 44 to 96 or 96 to 96, the data is completely re-made and the concept of bit-perfect upsampling is thrown out the window. The Wyred4Sound Remedy works like this. It works rather nicely too.

Almost all ASRC processes trade sample accuracy for timing accuracy.

Schiit is unique AFAIK in using "closed form" ASRC, in which they keep all the original samples, while adding interpolated data attempting to gain the timing accuracy without loosing the bit-perfection of the original signal. .

Google "closed form" and "Schiit" and you should find it.

Even so I went with Mytek. :)

Best,


Erik

P.S. Vendors often call ASRC something more cool sounding, like upsampling, resampling or, supreme de-jittering jitter jail. You have to read the details to find out if this is what they are doing.
whitestix OP
709 posts
 
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

sbank's avatar
sbank
3,378 posts
 
@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
ptss
1,964 posts
 
Whitestix I'd be interested to hear which 'pricey' power conditioner you use and of course how you use it.
williewonka
3,075 posts
 
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...

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