DAC Voltage - high volume to make it lower?

[Jungstar]

Most DACs put out 2V as a standard. Why so high?

This makes sense if we want to play at maximum volume, but with most power amps, we only want to play at 5-66% of max, and we rarely use more than 20 watts.

To produce 100W into 8 ohms with eg 23 db of gain we need 2V. But if we wanted to play normal listening levels we might only need 0.5V. My own power amp max out at 1.2V.

While making a loud signal makes room for adjusting the signal, erasing 80% of it, does also have drawbacks, I assume. This process of first creating a loud signal and then adjusting it seems like a setup from the past when preamps actually needed to boost signals. Now it seems the preamp section really needs to be good a removing volume, not having gain.

Is there not a better way to make the DAC create a desired "volume level" in the first place?

 

[Blumlein 88]

In essence what you are thinking about is gain staging. If your DAC puts out 2 volts then you'd like for 2 volts into your power amp to result in its maximum rated output. You would also want your speakers to play at their maximum rated loudness at the same time. With speakers it is really messy to define that. On top of that not all recordings are put together at the same average level. So for the few recordings that are recorded at lower level you need a little extra or those might not play loud enough. So having a little extra output from the source is useful in those cases.

Now we don't listen at max possible volume at all times. We don't likely even listen at the same volume at all times. So sometimes you will be turning down from max volume.

Looking at music the average level in many recordings is 15 to 20 db lower than max level. If it is 20 db that is a power factor of 100:1 on the peak to average level. So music with peaks of 100 watts in an amp would average maybe only 1 watt. So that isn't too far off of listening levels for many speakers.

The good news is modern DACs are so quiet with such a good signal to noise ratio, and 24 bit volume control is so good you can turn down the volume quite a bit and miss nothing.

Nonetheless, an example of poor gain staging would be super efficient horn speakers that maybe play 96 db SPL with 1 watt. A 100 watt amp that plays at 100 watts with 1 volt input and a source that max output is 4 volts. You might need to reduce volume by 50 db for normal listening with that combination of gear.

 

[staticV3]

While making a loud signal makes room for adjusting the signal, erasing 80% of it, does also have drawbacks, I assume.

Modern DACs have vanishingly low noise, making signal adjustment a non-issue.

 

[RayDunzl]

Most DACs put out 2V as a standard. Why so high?

2v isn't high.

Mine claims 12v, +24dBu

The preamp after takes care of the attenuation

The amp maxes with 2.53v

Why?

Design choice.

 

[unpluggged]

Most DACs put out 2V as a standard.

Most consumer DACs. Mine, for instance, outputs 12.28 V (+24 dBu). And my active speakers can accept such input levels.

Why so high?

It's a standard, as you said.

But if we wanted to play normal listening levels we might only need 0.5V

That's why volume control was invented.

 

[lini]

Most DACs put out 2V as a standard. Why so high?

Given that the usual 2 V(eff.) @ 0 dB(FS) were already introduced with the first CD players for home use a bit over 40 years ago, I deem it likely, that it would only seem natural for manufacturers of standalone DACs to usually stick to that (quasi-)standard, too.

Greetings from Munich!

Manfred / lini