DAC/Pre's Digital attenuation vs. analog

Using digital volume exclusively for volume control will result in a significant reduction in detail and imaging. It's okay to do about -9dB, but not more. This requires that the DAC have some kind of gain control or a good volume of its own.

There are five types of volume control:

1) Digital volume control - reduces resolution as the volume is decreased

2) resistive attenuation - delivers detail, but kills dynamics with most amps

3) active gain control - adds distortion, noise and compression, but has good drive, so dynamics are good.

4) Transformer scaling attenuation - with strong DAC outputs and good transformer linestages, like Music First TVC, this is more transparent and preserves the dynamics. Easy to match to amps

5) D/A reference voltage control - This volume adds no noise, distortion or compression, in fact it actually improves S/N ratio as the volume is decreased. No loss of resolution. The best of all possible options.

Steve N.
Empirical Audio

"5) D/A reference voltage control - This volume adds no noise, distortion or compression, in fact it actually improves S/N ratio as the volume is decreased. No loss of resolution. The best of all possible options."

Thanks Steve. How many companies make something like this and @ what price point?

Robertsong - there are two I believe, and Empirical Audio is one of them. $6K pricepoint for the DAC. Includes preamp, DAC and USB interface.

Steve N.
Empirical Audio

Isn't it fascinating how different well respected digital audio design engineers can express diametrically opposing views on something as basic as loss of resolution in digital volume controls or lack thereof. Engineering is supposed to be an exact science! In the absence of consensus I trust my ears, and ended up ditching a 10k preamp in favor of digital volume control.

04-26-12: Ivan_nosnibor
Hi Robert, whether going digital or analog with attenuation it's all really about the impedance matching.

please explain this statement as I do not understand how digital attenuation & impedance matching of source & power amp are related. Sources are usually very low output impedances digital attenuation or not.

So, a 32-bit player can offer 16 db of digital attenuation before reaching the 16-bit level,....

how did you come up with these numbers of 16dB of attenuation using a 32-b D/A?? Can you share your calculations? Thanks.
I think it's very wrong but it would be good to see your calculations before saying more.
Right now my CDP has a 24-b D/A that provides 50dB of total attenuation where at 50dB of attenuation you get zero output volume. So, how did your 32-b D/A provide only 16dB of attenuation?