Why are most High End Amps class A

So Kirkus,

What AMPS do you like and why if it does not matter if they are class A or class AB? Do you judge an amp mostly subjectively by sound or do you look for a particular construction?

It seems like you are a real expert in this area.

This may be a more general answer than you're looking for, but I like audio components that both sound good and measure well . . . and do so consistently, under a wide variety of conditions, for many years, without requiring much maintainance or repair. I generally feel that measurements are a good indication as to whether the engineering and execution are competent, and good sound is the indication that the basic design (and measurement methodology) is also competent.

To that end (to consistently sound good and measure well), I think there are some things that the best audio products have in common:
1. They are very well suited to the application
2. They make effective use of current technology and financial resources
3. They effectively solve the problems inherent in their basic design choices
4. They have quality and consistency in their execution

There are many topological choices that can fit this criteria well, both tube and transistor . . . just like there are so many different types of amplifiers that both sound good and measure well.

As far as Class A vs. Class B vs. Class AB . . . it's not that I don't think it doesn't matter, it's just that its very difficult to get a true class A design to meet criteria #1 and #2 above. For most solid-state Class AB or Class B amps, the main difficulty comes in meeting #3. For most Class AB or Class B tube amps, the difficulty comes on criteria #3 and #4.

I personally feel that these days, bipolar solid-state amplifiers show the most promise to meet all the criteria similarly well, but regardless of the basic choice of topology, it's a difficult road to get there. If I was designing a solid-state bipolar amplifier to drive a typical high-end domestic passive loudspeaker, I would choose a Class B design. If I was designing a tweeter amplifier for a high-end active loudspeaker, I would choose a class A design. If I was designing a tube amp, I would choose a Class AB design.

Kirkus, you are assuming rational thinking, whereas audiophile is a hobby. A hobby involves high-drive passionate pursuit for the best quality, such that other considerations seem far remote. For audiophile, that means getting the best sound for whatever money one can afford, or dare I say shouldn’t afford. As long as the equipment doesn’t break down often, nobody cares about anything else, except for a divorce if you spend too much money or make too much intrusion on the decorative well-being of your spouse.

My purpose of getting on Audiogon lately is to encourage people to check out Class A amplifiers, the real Class A stuff, if their pocket book can afford its price. Perhaps those in the borderline price range should wait for a while until they can own this good amplifier design. The sound gap between Class A and other classes is so wide that I cannot picture myself returning to Class AB. I am talking about how to retain the strengths of SS amplifiers and gain the values of tube amplifiers without their overkill. Music is a very potent medicine that can heal you in many ways, ways that the medical world could not provide. Yet for years I have such a tough time getting that quality sound at home, as opposed to a live concert with, somehow, less peripheral noises and proper sound projection. I am so much at awe with what true Class A amplifiers can do to my life that I just want people to check them out.

I am so much at awe with what true Class A amplifiers can do to my life that I just want people to check them out.

Spatine, I really don't disagree with you in any fundamental way - it's just that for me, I could say this about a number of different classifications of audio equipment, not just Class A amplifiers. And I do indeed value a rational, disciplined approach to the craft of designing and building audio equipment over a dogmatic approach . . . mainly because I consistently have positive musical experiences from systems that don't fit into any particular belief system.

A well-executed Class A amp can indeed show the true potential of solid-state amplification . . . I simply feel that it's possible these days for Class B amplification to be just as good (and better in some ways) if properly applied. It's just unfortunate that the market is brimming with too many examples to the contrary.

Kirkus - we're not talking about absolutely best amp in existence but about one that is about 100W/ch and less than $3k. Do you feel that class AB amps would have certain advantage here over class A (less estate = better components)?