......
The JC-1 are known to run pretty warm due to their high bias into Class A (which also accounts for them sounding so good).
No, the JC-1s sound as good as they do because of the efforts of John Curl (circuit topology and operating points), Carl Thompson (physical layout) and the late Bob Crump (component choice and voicing). Indeed, John Curl specifically chose an output stage operating point (bias) that he felt was optimal for that specific topology. Mr. Curls choice of a high bias was, no doubt, subjectively optimal (and probably optimal objectively) for his specific implementation and minimizes crossover distortion for that specific class AB amp.
But there is a serious danger in adopting simple orthodoxies as to what makes a great class AB solid state amplifier.
There are alternative methods to minimizing crossover distortions such as Self's 'blameless' output stage, that runs cool, which implemented by a designer such a Hugh Dean in his LifeForce poweramps, and who applies similar care in the rest of the topology, circuit layout and component choice, yields spectacular results.
Some of the worst 'improvements' I've heard in class AB amps were the result of folks thinking that high bias automatically yields improvements, and their simply turning the wick up.
I'm certainly not disputing the quality of the JC-1, but its qualities are not simply the result of high bias into class A; they're the result of careful attention to the topology and
appropriate operating points, as well as similar attention to layout and component choice.
FWIW,
Paul
