[Amps] Sweep tube amp by DL9AH, made by HB9AWI

[Angel Vilaseca]

Yes, to obtain tha beautiful cherry red glow of the plates :-) a better 
option would be to increase the plate voltage. With only 600 V from 
plate to cathode, the cathode current gets too high and the poor little 
cathode is soon exhausted :-).

73 de Angel Vilaseca HB9SLV


Pete Smith a écrit :
> At 02:58 AM 6/30/2009, you wrote:
>> I also took off the tubes and checked the emission of each tube last
>> night: Heater on for a couple of minutes, then cathode and grids
>> connected together and 50 Volts on the plate. Current was 0.05 mA for
>> one of the tubes. 0.10 - 0.12 for three of them and 0.20 for the last 
>> one.
>> I compared with a NOS PL519 I had. Current was 0.36 mA.
>
>
> Sounds right - I had a radio (FTDX-560) many years ago with sweep 
> tubes in the final that used to eat up final tubes at an alarming 
> rate.  After a year or so, they would decline so much in output that 
> replacing them was the only option.
>
> 73, Pete N4ZR
>
>>
>
>