This is for Georgehifi especially but others can chime in.

@audiotroy 
Sorry, pal, but you're flat out wrong. Only somebody who knows nothing about transistors would say the kinds of things you're saying. The optimum operating voltage for a transistor depends entirely on the characteristics of the transistor and how the circuit loads it. There is no silver bullet in just ramming more voltage through the silicon. You have no business advising people on audio gear, much less selling it. 

Khost are you a transistor designer?

Have you done any such experiments?

T plus A has why dont you talk to their engineers?

Could it be that if you use a higher voltage tranistor which is neccesitated by these designs that transistor run on that voltage rail runs with greater linearity than a lower voltage variation?

There are more variables then what you think.

I am sure you also believe that power cords dont work either?

You just cant run more voltage through the same device, it is called a high voltage circuit for a reason.

I think power cords are useful in that they do supply current from the wall to the gear (and my toaster, etc.), and any positive comments about gear from salesmen who carry the gear they comment about chews the fun out of the gum of any forum discussion.

I assume we are talking about MOSFET transistors on the output stage? Nothing new. Ideal for delivering extremely high current. Extremely high breakdown voltage. Low switching distortion and fail in a nice way (open circuit) which prevents too much collateral damage. Hafler started using these in the 80’s. 

I assume we are talking about MOSFET transistors on the output stage? Nothing new. Ideal for delivering extremely high current.

Bi-Polars (BJT's) are even better for giving current into low impedance's.

Cheers George