2. amps-preamps
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What are the advantages to a Class A amp & what are the trade offs?

I've never had a class a amp but am considering one now. So what am I getting myself into?
128x128artemus_5
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liamowen
193 posts
 
Mickeyb, what is the brand of amp you are using, if you don't mind me asking?
larrykell
122 posts
 
Once I listened to a Class A amp, many years ago, I never wanted to listen to anything else. Some of the older Class A amps used fans which increases your noise floor. The Sumo Gold I ran for a long time used to hit its thermal cutoffs in the summer so you’d lose a channel every once in a while and would have to shut it off until it cooled.

As I mentioned on other threads, I now own a Gryphon Colosseum stereo amp. I think it is one of the most beautiful amps I’ve ever seen and it doesn’t take up a lot of floor space because it is laid out vertically. It has two massive aluminum heat sinks.

What Class A amp are you considering?
bdp24's avatar
bdp24
9,411 posts
 

There is one maker of a well-regarded tube power amp (I’ll allow he and it to remain anonymous, so as to not appear to be "pushing" them) who offers the amp in both Class-A/B form, and in pure Class-A. Both versions share the same circuit architecture, power supply, tube compliment, etc, differing only in the biasing required to create each version.

The A/B version produces 100w into 4 and 8 ohms, the A version 40w. So why would anyone go with the 40w version? The designer claims (and there’s no reason to doubt him, at least in my mind) the Class-A version produces 1/10th the distortion of the A/B version. How audible is a tenfold decrease in measured distortion? I can’t answer that question.

artemus_5's avatar
artemus_5 OP
1,911 posts
 
@bdp24 
I learned long ago that the low powered amps sound better to me. I've had amps for 35wpc to 250 wpc. The 35wpc sounds best in my system. Unless one is pushing an 84db speaker load, high wattage is not needed. Even then, the low power may work. The amp I am considering is 40wpc and has pushed the 84db speakers
bigkidz
3,311 posts
 

I recently built a Class A 35wpc power amp based on the First Watt design.  The Class A was much better but I also use the best parts available and point-to-point wiring.  I also recently upgraded a few Counterpoint hybrid power amps with bipolar transistors with Class A output and the difference was much better. It added more clarity, depth, dimension and faster dynamics. You have to try them out for yourself as always.  I agree with the posts above mine.


Happy Listening.

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