[Bob Andersen]

Thanks for all the great info guys Greater sensitivity sounds like a good thing to me
I like that 19 output stage too - push-pull in one tube. I really hope the output transformer is good unlike my 643.

Both this set and the 643 use 135, 67.5, 2, -3 and -7.5 volts.
I've already been noodling around with some designs using the LR8N3 HV regulator as shown in this article by Leigh Bassett.