2. amps-preamps
  3. 125173-4976

can you alter the gain of an amplifier?

I never use active preamps and prefer sources with built-in volume controls over passive preamps when possible.  I've had great success using cd players by Consonance, Theta, & OPPO directly in my amp(s) but find that sometimes, even with the volume full up, the sound level is just not loud enough.  With my big, solid state amps, I know I'm not out of power, just not enough gain (this was particularly problematic with an Aleph clone).  I was wondering if it's possible/feasible to alter the gain of an amp to achieve better results using a passive volume control or the on-board volume control in the source?  I won't be doing the work myself.  I just want to know if a decent repair/mod shop could make the alterations.  Thanks!
lcherepkai
almarg's avatar
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almarg
9,670 posts
 
Interesting suggestion by Erik. A number of people have reported here and elsewhere that they have found Jensen transformers of various models to have essentially no sonic downside, while a few have reported a slight loss of transparency.

A minor correction, though: If the particular transformer doubles the signal voltage (which would be a 6 db increase in gain) it would result in the preamp seeing the amp's input impedance divided by four, not two.

Regards,
-- Al
lcherepkai OP
280 posts
 
Now, these are some fine responses.  Al, your advice is ever highly informative and always a pleasure to read (in my posts and many others).  Doug, you turned me on to bridging the Pathos Classic amps I have a Cambridge Audio 840W which I'll probably do the same with as funds allow but the desire to NOT have an active preamp is largely based on money.  The expense of a really good preamp is a deal breaker for me.  I've had a few decent ones from Celeste (by SIM Audio), Perreaux, and Antique Sound Labs and all were easily bettered by not having them in the audio chain.  I believe I had a Theta Miles and then a Consonance Droplet 5.0 with these 3 preamps.  I do pay attention to cabling and had quality cables/cords on hand so the preamps were handicapped in this way.  The sound was just obviously more open and detailed without the preamps.  And I didn't hear a reduction of dynamics or bass weight without the preamps.  Both of these CDP's had plenty on their own.  Perhaps a top notch preamp would take my system(s) to the next level but I just can't afford it.  And Erik,  I like your advice.  I'll look into the Jensen Transformers.  Thank you all very much!
erik_squires
16,389 posts
 
Whoops! Almarg is right, I was wrong. :)  It's been a while since I had to do transformer math, but you got the idea. :)

Best,


Erik
georgehifi's avatar
georgehifi
10,312 posts
 

It may be safer easier to up the gain on the output stage buffer of your source/s.

What amps do you have at the moment that you want to have more gain with?

Cheers George

bombaywalla's avatar
bombaywalla
1,958 posts
 
Whoops! Almarg is right, I was wrong. :) It's been a while since I had to do transformer math, but you got the idea. :)

Best,


Erik
yup! everything changes (up or down) by the square of the turns ratio....
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