Pass Labs xa - .5 amps

AFAIK there is no reason to think that any competently designed class a amp sliding into ab will damage speakers. The amount of class a delivered depends upon the bias current. Read Nelson Pass's paper on the subject on his web site. For high output solid state amps the inherent inefficiency of the design, however, requires huge power supplies, lots of heat production and large heavy heat sinks. Any manufacturer of a high output solid state " pure class a " amp which does not exhibit these characteristics is indeed exaggerating its capabilities. Reasons to choose ab over pure a include the desire for a small cool energy efficient amp or the need for very high output ( >500 watts) which is not very practical to achieve using class a. - Jim

Thanks for the clarification. I misunderstood. If by overdriving you mean clipping I would say that class a amps are not more prone to this.

Unsound you are correct in theory. The good news is that most companies which bother to produce such unwieldy beasts also care more than usual about quality because these are not produced for average audiophiles but for real old school die hards who don't care about size, heat, looks, efficiency or the latest " review". Spatine there are many well executed pure class a designs even though I admire Nelson Pass designs and have enjoyed talking to him from time to time about all things audio. - Jim