[rustydoglim]

We get asked quite often if any of the product uses analog volume pot, which lead us to think that people have a wrong idea about the performance or fit of analog volume pot in a digital (or mixed design).
I know many of you are expert in audio so please correct me if I stated incorrectly from what I have learned from our engineer.

In a traditional pure analog design, the best performance is switch resistor network for volume control but it is very expensive.
Next is a high quality volume pot (just like a network of resistors, you turn the pot to change the resistance which attenuates the volume). But volume pot is non linear and has balance issue at low volume.

Some DACs do not have volume control built in, so you have no choice but to do it at the analog output. We try to avoid that.  Fortunately the top DAC chips have volume control, which make sense because it is best to adjust the volume in the digital domain for digital signals.
DAC-9 and DAC-10* both have analog inputs and without A2D conversion. So we use mixed analog and digital volume control design.
The digital volume control of 0.5db steps are sent to the DAC for the best possible volume control.
The analog output from the DAC and the analog inputs from other source then go through a switch resistor network.
For the DAC's output, it just get switched "straight through" with minimum resistance. For analog inputs, the switch resistor network provides the best possible volume control. The digital volume control from the front panel manages how to switch the analog resistor network.

[aldcoll]

Swoooosh  The sound as that just blew over my head

Actually I did understand after a few times but my question is:

SO does the digital volume do anything to the digital output, i.e.  if a 44.1 file is playing at half volume does it become 22.05

Or is the volume changed in the DAC chip and all is well no need to read the engineers report

Alan

[srb]

Many modern DAC chips like the ESS implement 32-bit volume control, which means for 16-bit files you would have 16-bits of volume control for ~ 96dB of attenuation or for 24-bit files you would have 8 bits of volume control for ~ 48dB of attenuation before resolution would be affected.

(Or a few dB less attenuation for other technical reasons)

Steve

[firedog]

There are some DACs with 64 bit or higher digital volume control. With those you don't have to worry about losing audible bits

[srb]

There are some DACs with 64 bit or higher digital volume control. With those you don't have to worry about losing audible bits

And if you want to control volume through software, many media players such as Amarra, Audirvana, JRiver, Foobar, Pure Music, etc. also implement VC in 64-bit.

[les anderson]

Large companies like NAD have the capability and luxury to come up and source proprietary architectures that are not available to the smaller boutique shops. NADs current lineup includes 35 bit digital volume controls- theoretically perfect as far as I know with no loss of resolution, and no noise even at 24/192 and with lots of attenuation.

The catch is that for all this to work analog signals need to be converted to digital, and this becomes a slippery slope. I have had great experiences converting mid-fi analog setups to digital without any audible deterioration or coloration. However, if I had a $5-10k analog front end, I would be hesitant about sending it through an ADC.

So I think Nuprime may have found the best of both worlds. Interesting reading this as my suspicion was there was attention spent on the volume control of the DAC-9 but I hadn't read any detail until now.