As a semi-final coda to this saga, I've ordered a set of three [one spare]
6SH7 tubes and I'm actively looking for a good source for the 6AV5GTs as
well. I'm also looking to pick up on eBay a non-working HP 33x distortion
analyzer or similar oscillator from which to scrounge the dual tuning
capacitors so I can make a solid state low-distortion instrument as well.

I'll also look into replacing the electrolytic capacitors.

Thanks for all of your help and suggestions

Norm