19-05-2021, 09:01 AM
OK have played with the two MW36-24's my Fergy and the 14 inch tube with my test setup.
Test conditions are 6.3 Volt heaters with Cathode tied to heater and a 290 Volt HT applied to the g1 pin via a 300 Kohm resistor and a 1 mA meter, I also use a DVM across the g1 and K pins to measure the diode potential.
First of all my Fergy 991T which uses the MW36-24 tube, when I connected the tester the emission was very slow to rise after around 30 seconds be 0.2 mA and slowly increased to just over 0.5 mA with a few minutes use. The final diode potential was 131 Volts.
Tube A MW36-24 within 1 minute was at a diode potential of 6 Volts and very close to 1 mA current.
Tube B MW36-24 within 1 minute was at a diode potential of 48 Volts and current 0.8 mA.
The 14 inch tube diode potential at 16 Volts and close to 1 mA current.
I have not tried the 17 inch or round tube as I am trying to find data sheets to check heater voltages etc. But it looks promising for the tubes to be reasonable, now to get some Aquadag.
Adrian
Test conditions are 6.3 Volt heaters with Cathode tied to heater and a 290 Volt HT applied to the g1 pin via a 300 Kohm resistor and a 1 mA meter, I also use a DVM across the g1 and K pins to measure the diode potential.
First of all my Fergy 991T which uses the MW36-24 tube, when I connected the tester the emission was very slow to rise after around 30 seconds be 0.2 mA and slowly increased to just over 0.5 mA with a few minutes use. The final diode potential was 131 Volts.
Tube A MW36-24 within 1 minute was at a diode potential of 6 Volts and very close to 1 mA current.
Tube B MW36-24 within 1 minute was at a diode potential of 48 Volts and current 0.8 mA.
The 14 inch tube diode potential at 16 Volts and close to 1 mA current.
I have not tried the 17 inch or round tube as I am trying to find data sheets to check heater voltages etc. But it looks promising for the tubes to be reasonable, now to get some Aquadag.
Adrian
Learning as I go!
Youtube EF91 Valve
Youtube EF91 Valve
