Preamps built Into DACs

".....Well even the best S/W DSP volume controls seem to cause audible artifacts at more than about -9dB of volume reduction. No amount of dithering and resampling will help IMO....

There is absoltely no consensus on this, nor confirmation in listening tests. Lots of digital guru's will tell you -25db is fine. My personal experience confirms this."

I have a background implementing dithering and resampling algorithms for image processing applications used by the government and military. Not sure about this statement either. I would expect different yet comparable results in terms of accuracy to the alternative of not using digital if done well. Of course, that's always the big if with anything.

Also, the algorithms needed to accomplish optimal results have been well documented in academia for decades already and are old hat in the image processing world. I have no idea why it need cost a fortune to implement decent software based dithering and resampling to lower volume in home audio gear these days. That's why I like to buy gear that likes to advertise how their gear achieves performance, not just the claimed results. Then one can really know the value of what they buy if they care enough to do the homework.

In the case of DCS, specifically the newer more mega buck than ever Debussy gear, theirs is seemingly some of the most sophisticated home digital audio processing gear and software out there from what I read (with sound quality to match bsed on actual audition) but it comes for a hefty price. I would expect a very good perhaps reference implementation there that noone could fault based on technical approach nor listening.

Tru. I don't think all digital VC are created equal, and if someone sells a 100K dac with digital VC, they probably cracked the code on how to do it without losing reslution (or the minimal loss ofsets the loss incurred with analog VC). I mentioned the 64 bit megabucks Da Vinci and Totaldac, that also do digital VC.

This is important to me because I own the EMM Labs DAC2X, which currently has not VC, but its architecture allows for implementing digital VC through firmware. I am hopefull Ed Meitner joins the ranks of the digital VC done right crowd and delivers a stellar digital VC.

I am currently using the digital VC in my Trinnov processor, and according to the manufacturer at 50db attenutation I am losing information. Of course, this has not stopped them for using the exact same digital VC in the $40K ADA Reference SSP, so it can't be all that bad.

"I am currently using the digital VC in my Trinnov processor, and according to the manufacturer at 50db attenutation I am losing information."

Isn't loss of information a gradual thing with any volume control as the signal is attenuated? I don't think it just suddenly happens at some point. Attenuation might occur at different frequencies at slightly different rates for example with an analog control.

However each volume control, analog or digital might attenuate the signal slightly differently at each step, so no two necessarily are created equal. I would expect digital attenuation done right to be as good or perhaps even superior in terms of linearity and presenting what can be presented at any particular volume well.

Again, I suspect that this is another case where digital gets a bad rap categorically for no good reason. There has to be both good and bad digital and analog volume controls. ANy company that cares about good digital sound quality should be able to do it both well and in an affordable manner these days based on available technology. The technical challenge of implementing a good digital volume control algorithm would seem to be trivial compared say to the challenges of managing jitter as needed in real time during playback, IMHO.

Agree again. At the end of the day, all designs involve compromise. I don't really care if a VC is digital, analog, or hybrid, but just how it sounds. It stands to reason that with the advances in digital technology the gap has narrowed, and DCS digital VC in their 100K DAC suggest when you pull out all the stops, a digital VC can be superior or equivalent to the best that can be achieved analog. This is encouraging because digital technology tends to trickle down very fast. But again, the proof is in the hearing. FWIW, in the Stereophile review, out of the DCS debussy, Weiss 202 and Bel Canto 3.5, the reviewer preferred Bel Canto, which has Digital VC (the Weiss has not). The reviewer never even mentioned it - just reported what he was hearing.

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After reading all of the above, the high end tube preamp is the way to go for me. In five years as digital technology continues to evolve, I'll revisit the feasibility of using the preamp section of a DAC.
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