Thanks Gonk and psyprof1,

it helps to know that I need not worry. There is quite a difference in efficiency between the two types. Perhaps this will be an advantage for the amp, given it has only two toroidal transformers to share amongst all the five channels.

Well, one step at a time. I should have it completed within the next three or four months ... I can't wait. I'm already very pleased.

Again, thanks for the responses.

John