Hi Ed, Thanks for your efforts. I've opened it up and found an electrolytic with June 1963 stamped on it, so I'm sure your looking in the right area
.
It's the different B9A plugs Jason used to match speaker impedance and change negative feedback that I'm particularly interested in. Maybe info on other Jason amps, with EL84 push pull output (if they made any) would help me out?
Regards
David