04-02-2020, 08:39 PM
Jeffrey.
Find a valve, any valve with a heater rating similar to the tube, connect a dmm set on say the 2mA range, between cathode and control grid.
Power the heater at a verified 6.3Vac and note the current on the dmm, for argument it may be 500uA, (you are measuring the current driven by the space charge). When you arange your monitors internal heater supply, test with the same valve and aim to be as close to the current that you noted in the first test as you can, the result will be absolute.
Thanks,
Amie.
Find a valve, any valve with a heater rating similar to the tube, connect a dmm set on say the 2mA range, between cathode and control grid.
Power the heater at a verified 6.3Vac and note the current on the dmm, for argument it may be 500uA, (you are measuring the current driven by the space charge). When you arange your monitors internal heater supply, test with the same valve and aim to be as close to the current that you noted in the first test as you can, the result will be absolute.
Thanks,
Amie.
