Audio Systems: how to adjust gain control on power-amp?, adcom gtp, power amp

Question
thank you so much for your reply.  i can tell you know what you're talking about.  

i did loosely try something similar to what you said.  even with the amp's gain turned almost all the way down, i don't think i was able to get the volume know more then a few clicks up.  

however, now that i know more precisely what to do, i'm going to give it another try.  :)
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Followup To

Question -
hello -

i have the onkyo m-282 amp. it's curently hooked up to an adcom gtp-500 pre-tuner.

the back of the amp has an input-level adjustment (which i thought was kind of weird ... i would prefer no adjustment at all). according to the manual, they say you should crank it over all the way to max.

now that sounds like a good idea, but i've always been hesitant to "push" any elecronic adjustment (input, bass, treble, volume, whatever) all the way to max. it just seems to stress out the component and degrade the sound.

that being said, whenever i keep the amp at max, i can barely turn up the volume on my pre-tuner (which is kinda of cool, but kind of annoying).

so, after all that, my question is how do you all think i should adjust the amp? right now i have it about 3/4 of the way up.

thx,

ted

Answer -
Hi Ted,
  You have stumbled on a great technical question, and one of the finer points that is often ignored that robs any system of its best.  Thank you so much for asking it!

  This is a question about "Gain Structure".  If you google it I'm sure it will pop up god knows how many multiple-page technical discussions, but in your case it boils down to this:

Get the cleanest signal to the amp, and turn the amp up last.

More specifically, get your preamp knob to some good intermediate level - I'll loosely predict approx. 3/4 of the way up (maybe more) - one that leaves you enough room to "crank it" when you want to rock out without distortion.
Then, go to the amp and turn it up to where you think that intermediate volume level should be - I'd say 80-83dB - between "a TV that still allows you to talk over it" and "a vacuum cleaner".

Usually in consumer-grade equipment, a good goal to set would be to make your SIL (standard intermediate level) the point where the volume knobs on all equipment are set equally (i.e. at a normal operating level both your pre volume knob and your amp gain knob are at 3/4 to max).  This is just a rule of thumb, not a hard-set standard.

Without the benefit of pro-level equipment or sound meters to monitor what's going on, you're going to have to use your subjective judgement.  If something doesn't sound right, turn the amp all the way down, back off on the pre, and try again. If you get stuck, just query me again.

Here's a decent techy definition, and more simple explanation, if you want to know more:
http://www.community.chester.pa.us/files/technote/gainbasc.pdf?PHPSESSID=34d641e
http://www.sweetwater.com/expert-center/glossary/t--GainStructure


Answer
If it helps, most of my amp bank is set to "4"...
Just use common sense
- if you hear clipping or distortion the pre is porbably too high.
- if you hear static or noise during quiet passages you need to lower the amp gain and increase the pre.

Anything between that will probably serve you well.

Best of luck.