Higher-End Class A/B vs. Class A Integrateds

I’ve been thinking about downsizing from separates to an integrated amp. I’ve noticed that some companies have both class A and class A/B amps that are both pretty expensive such as Luxman for example. Hegel seems to be well received and they’re not true class A as far as I know.

I was kind of under the impression that class A was better than class A/B due to lower distortion yet again, there are some well reviewed class A/B amps that are as pricey as some class A amps.

To be clear, it’s really not the price I’m concerned about. It’s the fact that some integrated amps $5000 and up are still only Class AB.

How do these higher priced class AB amps sound in comparison to true class A amps?


Thanks for all the advice and suggestions.  I realize now that I'm not tied down to class a.   My tubed power amp puts out 40wpc with the EL34 tubes in.  I can get more with the kt88's but I don't seem to need the extra power.

It seems the Krell K-300i puts out supposedly 90 watts class a power so it appears that is pretty much my only option if I want class a power to spare.

After reading some good folks posts, I'm more open to the idea of a smooth sounding class ab integrated that won't sound puny in comparison to a low watt class a amp.

+1 for the Coda CSiB. I have the v1 which is 150 watts per channel into 8 ohms with the first 18 watts in class A. I use it to drive a pair of difficult to drive Thiel CS 2.4 speakers, and it handles the task with ease.  Most highly recommended.

It's a matter of execution.  I've a Sugden Class A 33 wpc, Luxman A/B 120 wpc. They sound different, but both drive well the ATC 20s, sealed cabinet.  Both exhibit lots of control and drive.

I would suppose the right difficult load could present problems for the Sugden, but I've yet to find that and it's driven lots of different speakers.  The bass from the Sugden is not booming, but it is lightning fast and clean.

Most claimed Class A amps drift into Class A/B after the first few watts anyway.  So then what do we really have?  Just listen with your ears.


Class A amplifiers have no crossover distortion at the 0 point because they use a “single” device to handle a complete waveform. This structure is incredibly power consuming, heat creating, and low on efficiency (usually around 25%) and power (25-30W is an average ouput).

Class B amplifiers use two, or more, devices in a complementary pairing with the “top” one handling the positive half of the waveform and the “bottom” one handling the negative half. The two outputs are then summed to give you the complete waveform with the point that the waveform goes from positive to negative (and back) being called the crossover point. Because of the lack of perfect linearity between devices there will always be some distortion at the point of crossover. Class B amplifiers are usually used for high power work.

A class A/B amplifier uses a class A stage for low power work and then “switches” to the class B stage for higher power work.  

See https://en.wikipedia.org/wiki/Power_amplifier_classes for help, too.