How do you match the output level of your dac to the input sensitivity of amp?

[humblebee]

Since sending signals below amp's input sensitivity will cause loss of audio signals and exceeding by much may cause damage by over-driving of amp.

 

[shibashis]

Is the DAC being used as a preamp as well?

 

[Fantastic]

Since sending signals below amp's input sensitivity will cause loss of audio signals and exceeding by much may cause damage by over-driving of amp.

I don't know where you get this kind of information ! Did you read it or thought it up by yourself ?

Amp sensitivity means that it needs 'that signal level' to produce full output at maximum rotation of the volume control. If you provide less than that , you cannot get full output from the amp on full rotation of the volume control. If you provide 'more signal' at the input then you will get full output ( clipping level, distorted level ) at some point 'less than' full rotation. It has nothing to do with 'loss of signal' at all.

When you connect a signal to an amp , say from a Bluray player , the signal level at the RCA connector is at maximum ( say 2 Volts).
The signal into your power amp 'circuit' is ZERO if the volume control is at zero. And it rises as you turn up the volume control . Did you find loss of signal at low volume ?......according to what you are saying the signal 'into' your power amp circuit at that time is 'less than ' the sensitivity of the amp and so should 'loose' some audio (?) !
The volume control is like a control 'gate' which allows more or less signal into the power amp depending on it's position.......resulting in higher or lower volume.
So even if you provide 10 volts to the input socket you will not overload the amp. What will happen is that the volume will rise more rapidly with volume control rotation and it will reach the maximum ( clipping ) level at say 1/5th full rotation. Nothing wrong with that except that small amounts of rotation will cause huge volume variation and make small adjustments in volume more difficult ( fiddly !).
All you need to know is if the signal level is sufficient to get full volume from the amp " when you are having a party " or get drunk or are high or insane etc. For normal use even lower input levels are Ok as you don't usually play the amp that loud. You just have to turn up the volume control more than with a high input level.
And also remember that input signals are 'fluctuating' all the time. While playing music at say 1 watt average ( quite a normal level !) the peaks in the same music might be at 10 watts at times ( maybe drum beats etc!).

No body 'matches' input signals to amplifiers because most signals come from DAC's and those are typically 2 volts max ( or at least about 1 volt) . Most amps will give full output with just 1 volt . Check the specs. Only catch is if you use signals from small portable devices or phono RIAA preamps ( for vinyl playback ) which might give lower output levels. Use a preamp to handle that !
Often nothing is required. You will most likely be able to get enough volume from the amp. Don't be too concerned about the position of the volume control. It also doesn't matter if the input levels are very low as long as you can play the music as loud as you want ! If that means you need max rotation of the volume control....it doesn't matter ! You ARE getting the volume you want .

 

[humblebee]

I have one of those professional sound cards that have mixers etc. So I can set output levels in db at RCA out jacks.
Now, I did notice that when I set these levels of sound card higher, I was getting more musical details FOR THE SAME ACTUAL VOLUME (not volume knob position) from the integrated amp that I have.
And clipping you yourself mentioned. So, my statement is altogether fine.

 

[doors666]

I have one of those professional sound cards that have mixers etc. So I can set output levels in db at RCA out jacks.
Now, I did notice that when I set these levels of sound card higher, I was getting more musical details FOR THE SAME ACTUAL VOLUME (not volume knob position) from the integrated amp that I have.
And clipping you yourself mentioned. So, my statement is altogether fine.

check for ENOB - effective number of bits

 

[humblebee]

ENOB is used in ADC.
I have searched also but I am unable to understand how it applies here.

 

[doors666]

there is no analog volume control in a dac, its done in digital domain, it starts throwing away bits when u reduce the volume, resulting in quality loss. keep sound card volume full, use an analog volume control (pot or stepped attenuator) in your chain after the dac.

 

[corElement]

there is no analog volume control in a dac, its done in digital domain, it starts throwing away bits when u reduce the volume, resulting in quality loss. keep sound card volume full, use an analog volume control (pot or stepped attenuator) in your chain after the dac.

In case of soundcard with xonar where there is a preamp and then seperate volume, one can adjust the preamp for left and right to lower and raise it if the floor noise level needs adjustment. Because if one pushes the preamp to max there is horrible distortion. I've found 60-78 to be the best range for the essence stx.

 

[ranjeetrain]

Since sending signals below amp's input sensitivity will cause loss of audio signals and exceeding by much may cause damage by over-driving of amp.

Amps tend to sound best around 40-50% volume. Theoretically digital sources should be played at full volume. If that arrangement sounds harsh, decrease volume at digital source. If it sounds thin increase it. Tune by ear which combination sounds most effortless.

 

[cyber_cat]

which sound card/amp ?

Are you trying to match proaudio soundcard to hifi amp ?

 

[humblebee]

OK I have tried something and the results are great. Any feedback by those who know The Way of The HiFi will be welcome ;-)
I think this will also apply to all sound cards. Turn its digital level to 100% and change the analog output levels. That way lesser audio loss.

So my card, M-Audio audiophile 2496 has max output at +2dBV (shown as 0 db on volume adjustment mixer levels)
+2dbV = 1.26 Vrms (consumer line level = 1.4 Vrms) (this is Vout)
Amp input sensitivity = 200mV (this is Vin)
Vout/Vin = 6.3 (7 for line level)
Gain = 20xLog (Vout/Vin) = 16 (calculators available online)
Therefore, if I set my volume to -16db on mixer level scale, I output 200mV to my amp.
This will not only help amp be driven to its max potential, but it is also giving more audio signals than I hear when I set it to say -25db for the same perceived volume. Plus no fear of amp clipping if I mistakenly set amp volume too high.

I hope this is right application.

For consumer cards like Xonar, where output is not shown in db, either dig out tech data of card or levels etc.
Or maybe after setting digital volume to max, the analog levels need to be set like this:
If you can find what the max and lowest volume analog levels correspond to, you can set knob accordingly.
For e.g. if max = 0db & min = - 90db
And your gain = 18 from above calculations, then you need to set knob at -18db which corresponds to 4/5 of max knob position.

 

[jls001]

-16 dB is set in digital or analog domain?

 

[Kannan]

Interesting topic. I was/am also in a similar dilemma.
My source is a bluray player which probably puts out max 2 volts. But it is anyhow digitally connected to the audioengine DAC which has a volume pot with 2 volt max output as per its specs. The headphone output of the DAC is rated at 10 ohms, no impedance details provided for its RCA outputs.
It was connected to the power amp via the DBX 234xs crossover. The gain pots are set at 0db in the crossover. (The crossover's input rating is 25000 ohms (unbalanced) 50000 ohms (balanced) with max input of 10 volts; output rating is 100 ohm/200 ohm unbalanced/balanced with max output of 9 volts ).
The power amp is rated for max input of 300 millivolts and a sensitivity of 47000 ohms.

The Audioengine was struggling to drive the power amp to its potential.
I then inserted my Onkyo Integra Amp (with active preamp features) after the DAC and before the XO. The Onkyo which is functioning as a preamp is driving the poweramp very well.
It has tone defeat feature which is quite a plus.

Now I am wondering if a passive preamp will work.
A friend of mine suggested to try an active DI Box like the Behringer DI120.
Else will have to keep the hunt on for a DAC cum preamp with balanced outputs.

I also read the thread by our member srisaikat who had written about his experience with the Schitt SYS passive preamp.

 

[humblebee]

Card has analog output stage.
But I believe that even for digital domain, integral multiples minimize audio data loss. For e.g. 50% volume would multiply all audio bit values by .5 which is better than say multiplication by .55.

The good thing is that the amount of jump in musical details that has occurred due to this is about the same that occurs when we move from about 256kbps MP3 to CD/FLAC file.

 

[aarmath]

I was about to call out on the nonsense but you did with intricate detail. Nice one mate.

I don't know where you get this kind of information ! Did you read it or thought it up by yourself ?

Amp sensitivity means that it needs 'that signal level' to produce full output at maximum rotation of the volume control. If you provide less than that , you cannot get full output from the amp on full rotation of the volume control. If you provide 'more signal' at the input then you will get full output ( clipping level, distorted level ) at some point 'less than' full rotation. It has nothing to do with 'loss of signal' at all.

When you connect a signal to an amp , say from a Bluray player , the signal level at the RCA connector is at maximum ( say 2 Volts).
The signal into your power amp 'circuit' is ZERO if the volume control is at zero. And it rises as you turn up the volume control . Did you find loss of signal at low volume ?......according to what you are saying the signal 'into' your power amp circuit at that time is 'less than ' the sensitivity of the amp and so should 'loose' some audio (?) !
The volume control is like a control 'gate' which allows more or less signal into the power amp depending on it's position.......resulting in higher or lower volume.
So even if you provide 10 volts to the input socket you will not overload the amp. What will happen is that the volume will rise more rapidly with volume control rotation and it will reach the maximum ( clipping ) level at say 1/5th full rotation. Nothing wrong with that except that small amounts of rotation will cause huge volume variation and make small adjustments in volume more difficult ( fiddly !).
All you need to know is if the signal level is sufficient to get full volume from the amp " when you are having a party " or get drunk or are high or insane etc. For normal use even lower input levels are Ok as you don't usually play the amp that loud. You just have to turn up the volume control more than with a high input level.
And also remember that input signals are 'fluctuating' all the time. While playing music at say 1 watt average ( quite a normal level !) the peaks in the same music might be at 10 watts at times ( maybe drum beats etc!).

No body 'matches' input signals to amplifiers because most signals come from DAC's and those are typically 2 volts max ( or at least about 1 volt) . Most amps will give full output with just 1 volt . Check the specs. Only catch is if you use signals from small portable devices or phono RIAA preamps ( for vinyl playback ) which might give lower output levels. Use a preamp to handle that !
Often nothing is required. You will most likely be able to get enough volume from the amp. Don't be too concerned about the position of the volume control. It also doesn't matter if the input levels are very low as long as you can play the music as loud as you want ! If that means you need max rotation of the volume control....it doesn't matter ! You ARE getting the volume you want .