Total system gain

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werd

Re: Total system gain
« Reply #20 on: 19 Jun 2012, 03:16 am »
Davey is correct. In my case about 1volt peak output from my USB DAC in a system with 26dB gain and 96dB speakers can be insufficient.  I have a few CDs ripped to wave that could another use another 6dB of gain even when I have my volume pot at maximum. Rather than look for another preamp, I will probably have a friend re-record the CDs with 6dB more gain.
Scotty

Is that 1v per channel ?

*Scotty*

Re: Total system gain
« Reply #21 on: 19 Jun 2012, 03:36 am »
Yes, it is a custom USB DAC and slightly over 1 volt peak out is all it has.
Scotty

vortrex

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Re: Total system gain
« Reply #22 on: 19 Jun 2012, 03:47 am »
if I have 2.4mv cart to 44db phone pre to an amp with 25db gain to 88db speakers, am I missing out on anything?  sounds great to me and I only listen at moderate levels.

Davey

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Re: Total system gain
« Reply #23 on: 19 Jun 2012, 04:04 am »
Scotty,

If you have them ripped to .wav you can easily normalize the volume to a higher level.  No need to have them re-recorded.  Re-burn to CD though, if that's what you meant.

Try Goldwave or one of the other audio processing programs.  Very handy.

Vortrex,

You might notice a system gain "problem" by the position of your preamp volume control.  Is it below 12 o'clock all the time and sometimes below 9 o'clock?  That's an indication you have too much gain in your system.
Of course, when you bring vinyl into the picture it can become even more complicated.  :)  I've noticed many contemporary preamps don't have enough gain in the phono section and too much gain in the line-amp section.  The Audible Illusions preamps are like this.  Not very well suited for line level source components.....and also horrible useability because of separate L/R volume controls......but that's a another subject.  :)

Cheers,

Dave.

*Scotty*

Re: Total system gain
« Reply #24 on: 19 Jun 2012, 04:14 am »
I wouldn't worry about it if you can hit the SPLs you want on your records.
My phono stage with about 40db of gain sees half of the output of my 5mv cartridge and only my copy of the Tron soundtrack requires that I peg the volume pot on my preamp.
 Due to the variations in the way records are cut the nominal 5mv output is usually exceeded by a large margin in actual practice.
Thanks for the tip on Goldwave Dave, I hadn't looked for any software online to do this yet and yes I meant that I would send off a burned copy of the CD to be re-burned at a higher recording level.
Scotty

vortrex

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Re: Total system gain
« Reply #25 on: 19 Jun 2012, 04:24 am »
Vortrex,

You might notice a system gain "problem" by the position of your preamp volume control.  Is it below 12 o'clock all the time and sometimes below 9 o'clock?  That's an indication you have too much gain in your system.
Of course, when you bring vinyl into the picture it can become even more complicated.  :)  I've noticed many contemporary preamps don't have enough gain in the phono section and too much gain in the line-amp section.  The Audible Illusions preamps are like this.  Not very well suited for line level source components.....and also horrible useability because of separate L/R volume controls......but that's a another subject.  :)

Cheers,

Dave.

for the average record it's at the 11-12 o clock position for a moderate listening level.  I should have maybe been more clear, but I have no line stage in my system adding additional gain (the volume control is on my phono pre).

I still don't quite get all the different pieces to this puzzle I guess, especially after reading that link which was posted!

FullRangeMan

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Re: Total system gain
« Reply #26 on: 19 Jun 2012, 04:26 am »
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sts9fan

Re: Total system gain
« Reply #27 on: 19 Jun 2012, 12:50 pm »
If you don't have a signal to noise issue then you have no gain issue. If you can crank it as loud as you want, you have no gain issue.

Davey

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Re: Total system gain
« Reply #28 on: 19 Jun 2012, 03:48 pm »
If you don't have a signal to noise issue then you have no gain issue. If you can crank it as loud as you want, you have no gain issue.

Well, it's not quite that simple.  :)  There are useability concerns as well as just signal and/or noise issues.

If you have so much gain that your system volume control is down in the 9 o'clock range then you have an issue.  Left/right channel matching will/might degrade and the action can become "hair-trigger."

There may be issues if the volume control is digitally implemented vice analog.

If not using a line-amp stage interconnect cable loading might be affecting the operation of the volume control.

Etc, etc.

Cheers,

Dave.

Freo-1

Re: Total system gain
« Reply #29 on: 19 Jun 2012, 08:07 pm »
I do not concur that db per watt is a useless spec.  It’s (just) a spec (like many others), and can provide some insight into performance.  I would concur that some specs are more useful than others.
 
Why, for example, do you think Papa Pass made the F4?  It provides zero db gain, but puts out 25 wpc in stereo or 100 watts in mono.  Just the ticket for someone who loves the sound of a flea powered amp, but needs watts to drive the speakers. 

Rclark

Re: Total system gain
« Reply #30 on: 19 Jun 2012, 08:28 pm »
why do car amps or sub amps have adjustable gain but hifi amps are stuck unless you perform surgery?

sts9fan

Re: Total system gain
« Reply #31 on: 19 Jun 2012, 08:48 pm »
That's not a universal truth. Many home equipment has adjustable gain. Not many power amps though.

Freo-1

Re: Total system gain
« Reply #32 on: 19 Jun 2012, 08:59 pm »
A lot of the McIntosh amps have gain settings.

jeffreybehr

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Re: Total system gain
« Reply #33 on: 19 Jun 2012, 09:25 pm »
I am a firm believer that modern components have too much gain.  You do not need a pre with 14db and a power amp with 32db.

Oh so true.  I haven't searched for components based on Voltage gain or Voltage output, but once one falls in love with chunks of equipment at some point(s) of the system, other components' Voltage gains should be sort-of-matched around it/them.  For instance, if one has low-sensitivity (as in...say...my c. 87dB V-steen 5As), looking for a poweramp with low output Voltage (= low power) probably is not smart.  I fell in love with a vacuumtubed multichannel preamp/linestage, a c-j MET1, that has 25dB of gain.  After buying McCormack DNA-750 poweramps that drive the V-steens effortlessly, I reduced (by almost 20dB) the '750s' Voltage gain so that I could run the preamp in its Voltage-gain, not Voltage-cut, range.  On very soft passages (of Classical music), I infrequently run the preamp ALL the way up.  It doesn't stay that way for long, but it can be done.

So my 'system-gain filosofy' is that one ought to balance Voltage gain within the system so that one is running one's preamp in the gain and not cut range and hence NOT excessively amplifying fixed-level noise from the frontend.

jeffreybehr

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Re: Total system gain
« Reply #34 on: 19 Jun 2012, 09:32 pm »
if I have 2.4mv cart to 44db phone pre to an amp with 25db gain to 88db speakers, am I missing out on anything?

Yes--the linestage gain, but maybe you don't have one...and reading further, I see that you don't.

sts9fan

Re: Total system gain
« Reply #35 on: 19 Jun 2012, 09:47 pm »
Your pre is still amplifying the signal. The signal is just being attenuated.

Davey

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Re: Total system gain
« Reply #36 on: 20 Jun 2012, 01:12 am »
I do not concur that db per watt is a useless spec.  It’s (just) a spec (like many others), and can provide some insight into performance.  I would concur that some specs are more useful than others.
 
Why, for example, do you think Papa Pass made the F4?  It provides zero db gain, but puts out 25 wpc in stereo or 100 watts in mono.  Just the ticket for someone who loves the sound of a flea powered amp, but needs watts to drive the speakers.

That's my point.  Voltage gain and current gain are two different parameters and can be applied in any combination to a design.

If I want a device with voltage gain that doesn't need to supply current to a load, I can build a preamplifier line stage.
If I want a device with current gain but no voltage gain I might build something like the Firstwatt.

So, they're two different things and relating them with some type of "ratio" specification is meaningless.

Cheers,

Dave.