06-27-2018, 07:49 PM
OK probably easiest is remove the 6SK7 nearest 6SQ7, use jumper on pins 2 & 7 to maintain heater string. Reconnect set, if noise stops reinstall tube and do same for 6SA7. I'll guess it won't be necessary to go past that point but if noise is gone do same on first 6SK7.
Tom
