Digital Volume vs a Passive pre amp

[Iwf]

My streaming rig comprises Roon into a Chord Qutest, then straight to my power amp.

I’m able to apply digital volume control within Roon, but I’ve noticed when playing back DSD Roon will convert to apply the volume change , thus pure DSD is not sent to the DAC. The output of the DAC, even after setting to the lowest output is still too loud for easy listening

The alternative is to pass the output to a passive pre then to the power amps.

The question is thus whether I’m losing enough quality through the Roon conversion to outweigh putting an extra bit of kit, including more cables into the process.

I guess the third option is to swap out the Qutest for perhaps a Hugo 2 , which has a volume control.

I do recognise this may be a theoretical argument as I couldn’t probably hear an difference in any case

I’m ignoring any suggestions as to alternate DACs, as that’s a different subject.

 

[staticV3]

The question is thus whether I’m losing enough quality through the Roon conversion to outweigh putting an extra bit of kit, including more cables into the process.

Can you hear the Qutest's noise floor as hiss from your speakers, at your MLP?

Then you have gain mismatch, reducing the effective playback DR.

If your speakers are silent, then any optimizations regarding volume control are purely academic and won't affect your listening experience.

 

[Iwf]

Thankfully I can’t hear any noise floor at all, and perhaps the only way to confirm is for some listening tests

 

[bryan0101]

passive in analog domain will sound better. Get something like a goldpoint, basically a single resistor in signal path, it will have better detail than truncating the source in digital domain.

 

[Purité Audio]

passive in analog domain will sound better. Get something like a goldpoint, basically a single resistor in signal path, it will have better detail than truncating the source in digital domain.

No.
Keith

 

[staticV3]

it will have better detail than truncating the source in digital domain.

Citation needed.

 

[Philbo King]

A resistor network attenuator switched by CMOS analog switches is electrically equivalent to a passive resistor attenuator (as long as the power supply is clean and digital grounding is properly implemented).

But I suppose this might fall into DIY territory...

SImpler yet is a chip that has all the grunt-work design done for you:

Volume control ICs | TI.com

Digitally-controlled volume amplifier and attenuator integrated circuits (ICs) with wide dynamic range and low distortion

www.ti.com

(though, arguably, no longer passive).

 

[AnalogSteph]

Citation needed.

Indeed. Roon works in 64-bit float and the DAC has 32-bit output, the odds of there being too little noise in the signal for adequate dithering are extremely slim. Plus the approximate undithered dynamic range for a 32-bit DAC would still be ~168 dB.... that's a lot to spare.

 

[Rednaxela]

This thread is only about DSD playback right?

If so, I suggest this to be reflected in the title.

 

[antcollinet]

The question is thus whether I’m losing enough quality through the Roon conversion

If Roon are doing the conversion correctly, and it seems vanishingly unlikely that they are not, then the answer is:

no, you are not losing any audible quality at all, let alone enough to compensate for for the noise and distortion added by a passive volume control.

 

[dlovesmusic]

I don’t use roon. Can you use roon to convert dsd source to pcm before feeding it to the qutest? That might potentially address that volume mismatch issue.

There is not much point to feed dsd source to the qutest anyway since the qutest will convert it back to pcm at the end

 

[JeremyFife]

My streaming rig comprises Roon into a Chord Qutest, then straight to my power amp.

I’m able to apply digital volume control within Roon, but I’ve noticed when playing back DSD Roon will convert to apply the volume change , thus pure DSD is not sent to the DAC. The output of the DAC, even after setting to the lowest output is still too loud for easy listening

The alternative is to pass the output to a passive pre then to the power amps.

The question is thus whether I’m losing enough quality through the Roon conversion to outweigh putting an extra bit of kit, including more cables into the process.

I guess the third option is to swap out the Qutest for perhaps a Hugo 2 , which has a volume control.

I do recognise this may be a theoretical argument as I couldn’t probably hear an difference in any case

I’m ignoring any suggestions as to alternate DACs, as that’s a different subject.

I think you are right: it's a theoretical argument and you won't hear a difference either way.

Choose a solution that functions well for you: ease of use + aesthetics

 

[solderdude]

Downsides to analog volume control (not being stepped/ladder) is a possible channel mismatch at the lower volume range settings.
Also... potmeters may become scratchy/intermittend after a awhile.

Downside to digital volume control is that when 'something' goes wrong like the volume set to max or some glitch happening the amplifier plays this at full power.
The same is true for volume control IC's.

Both can be done use remote volume control.
Both can have great tactile feel volume controls.

 

[Tom C]

Yes, it quite possible that with digital volume control, you can inadvertently turn the system on at full power, a most unhappy situation. With a physical volume knob, at least you can quickly grab it and turn it down.

 

[dlovesmusic]

I don’t know if other software supports that. With hqplayer, you can actually set max and min volume limit so you can never go pass that volume limit. When I was using hqplayer and dac connected directly to my power amp, I would try volume to my normal listening level say at -15db then set my maximum volume to never go pass -12db per se. I would also set my minimum volume at -35db since I would never listen to anything lower. I would just use the iPhone control app to control volume.

Rock solid, never had an issue.

 

[Iwf]

How about my other question? If I use digital volume control within Roon, the DSP engine will resample a DSD file down to 176 kHz to apply volume, thus the DAC isn’t getting DSD but 176 PCM

 

[DVDdoug]

How about my other question? If I use digital volume control within Roon, the DSP engine will resample a DSD file down to 176 kHz to apply volume, thus the DAC isn’t getting DSD but 176 PCM

I'd be shocked if you can hear a difference (in a proper blind ABX test). Most people can't hear a difference with ANYTHING down-sampled to "CD quality".

 

[Iwf]

I'd be shocked if you can hear a difference (in a proper blind ABX test). Most people can't hear a difference with ANYTHING down-sampled to "CD quality".

Slightly going off track, but I just found a SACD rip where I had ripped the CD layer and separately the SACD two channel layer. Ignoring a true blind test, going back and forth between the same track on both versions, I couldn’t hear blind bit of difference between either of them. So that DSD64 vs 44/16. My hearing is undoubtably not what it was 40 years ago when I started my hIfi journey, but nonetheless I was a little surprised.

I think I should perhaps forget about the trivial and non audible differences between hires versions and focus on decent recordings.

 

[tmtomh]

I don’t know if other software supports that. With hqplayer, you can actually set max and min volume limit so you can never go pass that volume limit. When I was using hqplayer and dac connected directly to my power amp, I would try volume to my normal listening level say at -15db then set my maximum volume to never go pass -12db per se. I would also set my minimum volume at -35db since I would never listen to anything lower. I would just use the iPhone control app to control volume.

Rock solid, never had an issue.

I believe GLM has similar functionality.

 

[antcollinet]

Slightly going off track, but I just found a SACD rip where I had ripped the CD layer and separately the SACD two channel layer. Ignoring a true blind test, going back and forth between the same track on both versions, I couldn’t hear blind bit of difference between either of them. So that DSD64 vs 44/16. My hearing is undoubtably not what it was 40 years ago when I started my hIfi journey, but nonetheless I was a little surprised.

I think I should perhaps forget about the trivial and non audible differences between hires versions and focus on decent recordings.

Almost no-one could distinguish in real world listening conditions.

And I am certain no-one could distinguish between DSD, and even 48/24 PCM under any listening conditions - let alone any higher rate PCM.