2. amps-preamps
  3. 1104601478

Using an amplifier with variable gain

I have an AudioSource Amp Two (80 wpc) that has variable output. I've had it for the last 5 or 6 years. Anyway, I've always put the gain at maximum. So, I control the volume using my preamp, but I can't turn the volume knob much past 2. Today, I was thinking about it, and I decided to turn down the gain on the amplifier to about 50%, and then turn up the volume on the preamp by a corresponding amount. My question is which situation should give the best result, in terms of sound quality? It' not easy for me to tell by ear, as I'm sure most of you would recommend to just listen. Is there any theoretical reason why one setup is better than other? Any advice is much appreciated.
ezamir
eldartford
4,262 posts
 
The best thing (in theory) would be to use a fixed attenuator (couple of resistors) at the power amp input, so that both pots can be near maximum. However, in practice, unless the power amp gain pot is noisy, setting it lower than maximum will be ok. If it is noisy, use contact cleaner on it.
sogood51
2,157 posts
 
The gain control on the amp should be set to max, if you read your manual I'm sure it states this. If you were to bi-amp with more gain on that amp...then you might back it off to balance the sound.

If the power amp gain is noisy, sell it...it's junk.

Dave
sean
6,231 posts
 
Inpep brings up some valid points that i overlooked. Kudo's to him for being on the ball.

The more signal that you pump into the amp, the less that line loss comes into play with the potential for a higher S/N ratio. You'll end up with both the preamp and amp potentiometers dialed at less than full gain this way, and depending on their quality and how well you can set channel balance, it could be better or worse. Try it both ways and see what you like best. This will be a system by system thing based on the individual design of the mating components, so nothing is set in stone. Sean
>
More to discover