• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.


Hi All, Just need help in Evaluation to make this amplifier work!
What do you see that needs to be corrected? Are these values going to work?
and Will I be able to use these valves in this setting? Any Info would be Appreciated!
very much! The 500 ohm primary and 1 ohm secondary of the output transformer
I believe is a DC Resistance reading.... What about a 6A5G? Lydia


  • 6Y6G.png
    924.6 KB · Views: 126
Last edited:

Sorry to say that your schematic is so full of errors that it's not going to make any sense trying to explain here what you did wrong.
Some errors are so basic, that if you don't immediately see them, like the negative-supply rectifier being the wrong way around, I would suggest that you keep off 300V circuits.
It just takes a bit more knowledge to start messing around with tube-circuits.



Don't you find it odd that the two 6Y6 symbols are drawn differently?
One as a pentode and the other as a triode.
Since it is a pentode it's going to miss some screen-grid feed in your circuit.
Also read-up on what current a control-grid (Grid-1) should draw. 90mA is a bit much ;)