Hi John : What a good answer to my question, I hope you don’t mind my response to your personal mail.
I did not mention that I have JFETs instead of a matching pair of 12au6s in both horizontal and vertical amps. The other 4 12au6s are still in use, with the heater voltages reduced with a 330 ohm power resistor.
The balance problem occurs in both horizontal and vertical amps. Do you think it worthwhile to put the JFETs where the remaining 12au6s are and the valves in place of the JFETs to see if the balance improves? The valves are not matched I don’t think.
Thanks again,
Jack