Class A amplifiers - which are considered the best

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.