Phil is probably right that I'll not gain much or ven anything from the
Hitachi design I have now.
But it will always niggle at me that there maybe a better design nowadays.
MOS appeals from the robustness angle but I'm not convinced it's best for
audio, relatively few manufacturers seem to go that route apart from in car
audio..........
So this is my current target

http://www.tech-diy.com/Amplifiers/L...702_Sanken.htm

I take on board that the SAP15's may go out of exisitence in the future but
I could always change the output stage to something else should the worst
happen.
I even have 2 pair of SAP01M fets but looking around they don't appear to be
stocked so they must have been a non-starter ( I got them as samples when
they came out )

thanks for all your comments.

Pete