Class A amplifiers - which are considered the best

Georgelofi, I did see your link. I believe that at the time Mark Levinson was building those amps, he was charting fairly new territory, and those amps were overbuilt. Compare the size, weight & number of chassis, to a newer Class A amp capable of similar Class A power output:

http://www.stereophile.com/content/pass-labs-xa305-power-amplifier-specifications

I think your overall point is well taken though. Some, if not many amps that suggest pure Class A output, are questionable in that regard.. The Aragon monos, the BEL's and some of the Electrocompaniet amplifiers amongst others, do appear to be stretching credibility with their Class A claims.

Unsound: Georgelofi, I did see your link. I believe that at the time Mark Levinson was building those amps, he was charting fairly new territory, and those amps were overbuilt. Compare the size, weight & number of chassis, to a newer Class A amp capable of similar Class A power output:Unsound

This was what they needed just for 25w class A only , as they were still hot, after an hour or two idling, my friend owned a pair and I correctly biased them to spec for him, any hotter and they would have been unreliable.

Nelson Pass's favourite saying on how much class A bias heat sinks can handle, after 2hr warm up, is palms of hands on heat sinks with >35c ambient temp day and you should to handle the heat for 4 sec, this is the absolute max class A bias for those heatsinks. (brick layers need not apply for this test) soft wimpy tech hands or females only.

Cheers George

The Krell KSA80, KMA160, et al were not Class A designs. They were Class A/B amplifiers, which operated with elevated Class A bias (usually to around 10% of their maximum power output). To the best of my knowledge, ONLY the fan cooled Krells were real Class A amps.

The KSA80 and KMA160 did preceed the KSA250, but they were still Class A/B amps. I have a brochure somewhere around where Krell acknowledge the power consuption of the amps. The power consumption is a dead giveaway that they were not Class A designs.

Love to see that brochure. In any event, they sure fooled me. Still thought they were great sounding amps. I couldn't get past the sound of those fans on their predecessors.