19-12-2020, 03:25 PM
These sets take a long time to warm up especially if the original PY81 boost diode is still present on the chassis.
Early PY81 valves have a ceramic tube inserted between the heater and cathode.
Geordie McBoyne.
Early PY81 valves have a ceramic tube inserted between the heater and cathode.
Geordie McBoyne.






