Do DAC volume controls sound best?

My dad was an electrical engineer. He died just as I was getting out of my surly teenage years. Mr. Paul explains things much the same way he did, patiently, clearly. Watching these is almost like having him back for a short while. What I wouldn’t give to have one more conversation!

If the volume is controlled at the dac, wouldn’t it be better to get rid of the preamp and connect directly to the power amp?

As opposed to the brakes on a car analogy, water faucets in the home would be a better analogy. The speed of a car is a variable that changes when the brakes are applied, and is in a different state when the brakes are let go. A faucet is working against a constant pressure (as Paul would says, "let's just call it pressure and not get in to the hydrodynamics") and the valve is obstructing the flow of water.

To quote Paul, "hope that helps!"

BTW, if this helps, please e-mail me a 50% coupon for one of your products. :)

While I'm in the comment section, I would like to applaud Paul for his incredible explanations of complex topics regarding hi-fi audio. There are very few places to get information like this without the explainer becoming snarky. Though I am skeptical about some of the stuff he has presented in his videos, I have learned not to dismiss some of the more esoteric concepts that I used to throw out.

Thanks.

Hey Paul Take listen to Audio Alchemy DDP1 and its beefy analog preamp , it is unique in design with its integrated and sound very open and analog like full of detail and space even at low volume levels .... Very easy and addictive to listen to ...

Yes, the DAC volume control will sound better because it has NO sound of it's own. It fully does away with pot non-linearities and channel imbalance issues. It's the best way to go. Next would be using a digital volume control chip, e.g. AD5207 or DS1802.

I remember working on a preamp with a digital volume control and it didn't sound very good. I upgraded the volume control chip and the sound improved but still not very good.

The analysis is correct. Unfortunately most of us have potentiometers somewhere in the system. The best designs, all other things being equal would be to have a lower impedance pot, say 25 K and the highest input impedance to the next stage, a tube or a mosfet. It should be located as close to the last stage of the preamp or doing away with the preamp altogether. The potentiometer puts a resistor in series with the signal. The stage to the input to the pot should have the lowest possible output impedance and a good power supply. Note that many speakers have series resistors in the crossover networks for gain matching. Adjusting the gain of a tube or transistor without changing sound quality is also tricky business requiring a lot of skill.

Lol. Props to the editor for fading out Paul as he got distracted

If you copy industry in high end audio consoles, the channel trims on some consoles are analog, but not an attenuator. They are inserted in the negative feedback loop. This controls the gain of the preamp stage so it can accommodate a wide variety of microphones and application. This controls SN ratio and keeps the preamplifier output constant maintaining constant headroom into the main channel faders, which when operated in their optimum range preserves system clarity and SN ratio into the mix of monitors, groups, and mains.

Going with analog multipliers (Voltage Controlled Amplifiers) there is a trade off. A passive resistive component adds no non linear distortion and thermal noise to the system while all active components in an added VCA, has a thermal noise figure and linearity distortions, which while quite low are present.

In pro audio as used in studios, the attenuators or channel faders on an analog mixing console are operated in the upper 3/4 of the rage for this reason and the individual channels first stage gain is controlled with the trim pots, which instead of being an attenuator, are actually in the stage negative feedback loop controlling the actual stage gain. Some lower priced gear do use attenuators here, but they have much worse signal to ratio issues.

Digital consoles skip the back end gain analog components altogether and adjust the gain by adjusting the digital math to scale the digital numbers to the final DAC. The analog signal inputs are still analog before the first ADC as the signal needs to be amplified into the range of the ADC for proper values to maintains SN ratio. Instead of a trim pot in the negative feedback section of the input preamp, a high quality VCA is used which maintains SN ratio over the wide range if input levels.

Hope this helps understand how the program material is recorded and mastered for your use with good clarity and SN ratio. Of course there are bad over compressed and processed junk for the mass market, but the good equipment is used by both. This covered how the industry can produce good audio at the source.

I found that replacing my preamp with my hybrid gain control DAC to be more transparent and less colored. Could just be the good or bad quality of my gear but there is a definite improvement. Sometimes I toss my preamp back into the mix just to remind myself of the difference.

I use the amp to control loudness and sometimes the DAC volume to adjust for the media's recorded level.

The channel balance with a 256 step (for example) digital attenuator can be very good. The log law (how closely the levels match the way we hear loudness) can also be excellent. Douglas Self raises an issue that confounds the channel matching requirement - most preamps NEED a balance control because speaker matching, room acoustics, the music, and our ears hardly ever center the stereo image at our listening position. A major downside to a digital volume control is what happens with a signal that is greater than the usual 2 volt limit - the signal clips which can lead to splashes of harmonics than can sound hard to our ears. Simply using two ALPS mono sliders (one for each channel) allows balance and volume control without the possibility of overload artefacts. BTW: for those of us who don't like getting up when we are relaxing in our sweet spot, there are motorized versions of the sliders.

Very helpful as usual paul. I just swapped out a DAC with a pot for same brand without. At first I had noise. First I purchased a much better toslink cable. Better, but... now no pot is even better still. Thanks.

Can you eliminate the preamp then in this case?

First video i like from this channel and i watched a lot (::

This realisation occured to me as it is an attenuator, so the better it is, better the output... Tc bmc-2 has "bit perfect" blinks when you hit every 6db if i recall... Budget, great dac !

Point-to-point = no PCB

So would it be better , if our dac has volume control , to just go directly from the dac to the power amp?

I have a Audioengine D1 conned to my Computer via Optical Audio Input; should i keep the windows volume at 100% or the DAC at 100%?

This volume is the same in DirectStream Jr ?

If feel like a complete idiot, but I don't care. This video finally hammered some sense into my head. As per the recommendation in the video, I turned the pot all the way up on my amp and used digital volume control in the Mola Mola Tambiqui and...My. Jaw. Is. On. The. Floor. I can't believe how much I was gimping my system by doing the opposite. I always heard/read it was better to control the volume in the analog stage (either that or I was completely misunderstanding what both people and literature were saying). Never again. Thanks, Paul!

HELP!

Great explanation as always, but I have introduced a DAC with no volume control so need to ask the question 🙈.


Oh I’m a bit late to this party 🙈…… so am I correct in thinking that I should have my motorised Accuphase Integrated amp cranked ‘Open’ & use the digital volume control on my BlueSound Node?

I have a Qutest DAC between the Node & the AMP but the Qutest does ‘not’ have a volume control.

Will it further optimise the quality by having the Accuphase set loud & use the digital volume from the streamer?

I don’t expect anyone to answer but would be very grateful to get one!!!!

I’ve honestly always wondered (to my ears at least), why does a receiver with a digital volume control sound thin, less richer/warm compared to a receiver with a mechanical volume pot? Drives me crazy that (to me at least) vintage audio gear, or gear that still uses a mechanical pot sounds better than digital controlled volume. I honestly just don’t get it, why does a digital volume control seem to sap so much richness, fullness and liveliness from an audio source?

I own an ADI-2 dac and use it as a pre amp. It works wonderfully. However, I plan on upgrading to monoblocks and wonder if I should get a true preamp to feed them. PS audio is on my list, of course I want the best sounding, most powerful that I can afford. I have about $4000 into my current system, apparently that is a drop in the bucket if I plan on going with monoblock set up. I just started shopping and realized the next level is a much, MUCH larger financial commitment. I understood this but some of these amps prices are insane.

Here he is saying 100% the preamp and choose correct volume on DAC. But what about if your AMP comes with a volume control? Does that mean the amp is using a POD, is a volume control always a POD? Also wouldn't 100% volume on an AMP give the max output watt of the amp e.g. a 300watt rated amp would then give 300watts and it would bloke a 100watt speaker?

I use Roon and a Parasound P5 preamp. It uses a pot. Should I set the P5 volume to max and control the volume from Roon’s dsp volume?

Yes for PSI products but generally if you use an Streaming player or digital volume control on the Computer, that should be on maximum level and level control should be used on Amp to get maximum Beat Depth!