Amplifier Gain - Implications

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miklorsmith

Amplifier Gain - Implications
« on: 21 Oct 2005, 03:34 pm »
I had the gain in my amp reduced.  I'm using very efficient speakers and this was really to get more usable volume control, not for any sonic reason.  Noise isn't an issue.

The question is whether this modification generally would produce a loss in dynamics.  I'm trying to think of this as a sine wave (obviously simplified for my ignorance).  The top of the wave is loudest and bottom  quietest.

Does lowering the gain reduce amplitude, or does it hold the relative relationship constant while merely lowering the absolute value (volume)?

Or, am I thinking about this all wrong?  Smart people?

Ancillary question - If the amp needs to have higher gain to preserve maximum dynamics, do I get right back to the same problem having the preamp modified?  Suggestions for best place for a gain reduction?

Thanks in advance.

topster

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Amplifier Gain - Implications
« Reply #1 on: 21 Oct 2005, 04:28 pm »
I'd think that for any given output volume level, you'll need to control the combination of gain in each component for your Zus. So it's either lowering the volume on your pre, or reducing the gain in the amp, or reducing the output of your source.

As long as you're not moving it out of the preferred range that the component was designed for, there shouldn't be any degradation in sound quality. For instance, my understanding is that pres operate best between a certain volume level, so if you're operating below or above that, it'll either not have enough drive, or it'll start to compress (or whatever the equivalent term is for electronics and tubes).

Well, that's my theory anyway.    :)

Steve

Re: Amplifier Gain - Implications
« Reply #2 on: 21 Oct 2005, 04:53 pm »
It is hard to say Miklor, because of some variables involved. Here are some examples below.

It will depend on what was done, plus the design of the amp. If a simple resistor dividing network is installed to cut the gain, the sound may stay the same.

Poor sounding or high value resistors would most likely hurt the sound. Either a little loss in the highs or sonic signature of poor resistors might be observed.

If a whole stage is eliminated, the sound should be better, unless the eliminated stage is also used to try to compensate for problems elsewhere in the amp's design/sound. Then the sound could actually be worse.

For instance, if added resistors had a poor dynamic signature, the amp may sound like it lost dynamics. Same with an eliminated stage whose tonal balanced favored the highs, which made the amp sound quicker, more dynamic, with more inner detail.

Or it might just sound the same. It is really hard to say until actually done.


Hope this helps Miklor.  :)

miklorsmith

Amplifier Gain - Implications
« Reply #3 on: 23 Oct 2005, 04:57 pm »
Thanks guys.  To close this particular loop, I had a guy here yesterday (thanks, MttBsh) that had a hi-gain Clari-T.  I knew in 5 seconds that mine needs to go back to get reworked to the stock gain setting.

Dynamics were exploding out of the speakers, where before things were a little polite, kinda like speakers of normal efficiency.  I thought things seemed a bit tame and now that's confirmed.

In my mind and in this application, it seems there is Definitely a reduction in dynamics when reducing gain of the Clari-T amplifier.

In this case, the gain was reduced by about half.

Vinnie R.

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Amplifier Gain - Implications
« Reply #4 on: 23 Oct 2005, 07:23 pm »
Quote from: miklorsmith
Thanks guys.  To close this particular loop, I had a guy here yesterday (thanks, MttBsh) that had a hi-gain Clari-T.  I knew in 5 seconds that mine needs to go back to get reworked to the stock gain setting.

Dynamics were exploding out of the speakers, where before things were a little polite, kinda like speakers of normal efficiency.  I thought things seemed a bit tame and now that's confirmed.

In my mind and in this application, it seems there is Definitely a reduction in dynamics when reducing gain of the Clari-T amplifier.

In this case, the gain was reduced by about half.


Hi Miklorsmith,

IMO, the gain of your Clari-T should be returned to stock setting and the gain of your tube preamp should be reduced, as it is wicked high!  :o

From our conversations, it seemed like it was an easier solution for me to reduce the gain of the Clari-T while I had it, but as you are finding, it may not have be the best solution.  Feel free to send your amp back to me for a gain adjustment.  The next step is to either reduce the gain of your preamp (or deal with the limited range of volume control because it gets loud too quickly), or reduce the voltage of your source.  I recommend you leave the source alone and tackle the preamp's gain.

Your ZUs are very efficient, so ideally your preamp would not have a gain above 0dB (ie, no gain, just attenuation).  This can be easily achieved if you use a passive volume control, but I know you like the flavor that is added by tubes before the amp, so it is probably best to have the preamp's gain reduced (as long as the manufacturer believes that there will be no sonic degradation).

If I can be of any help, please contact me.

Regards,

miklorsmith

Amplifier Gain - Implications
« Reply #5 on: 23 Oct 2005, 09:49 pm »
Thanks, Vin.  Amp is packaged up and will ship tomorrow.

On the pre, it stays in the system.  I've tried the system with and without.  Any loss in transparency (not that I can detect any) is hugely outweighed by the addition of space and depth to the sound.  It's not even close.

I offer that the soundstage feels four times deeper with the pre in the system.  That makes for a HUGE hole in the sound when it's out.

I'm a little worried that reducing the gain in the pre would have similar results.  So, LOUD might just be at 9:00 for me.

And this is with the Monica, who has yet to meet her match.  MttBsh and I both preferred it to the Nixon TubeDAC, though the Nixon is an excellent unit.  Matt - please correct me if I understand incorrectly.

markC

Amplifier Gain - Implications
« Reply #6 on: 27 Oct 2005, 01:59 am »
Perhaps different volume control/s would solve the problem? You can alter the input to you amp by choosing different db reduction in your preamp. e.g (9 0'clock could equal 11:30, but full out is still full out), just the  increments to get there are different. Check out gold point's web site for an example.