• 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.

#26 line stage help

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Ok I have finally gotten around to playing with the #26 again. I have B+ of 306V, plate resistor value of 43K, plate voltage of 133v. I have 10.0v across my 2.5K cathode resistor. I have a cathode by pass of 1000mfd. I am using a 2.0V 5AH battery with a .47 dropping resistor to end with 1.5V. If I understand the tech sheet correctly I should be ballpark and it should be ok.

The main problem still seems to be some small hum that seems to lower in level when I touch the chassis. Any thoughts on how to totally kick the hum to the curb? Now, I have read about every article I could find on the 26 and the hum problems and I thought the hum might go away using the battery for the heater feed. Any thoughts/comments? Thanks for the help in advance.

Joe
 
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