• 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.

problem with EL84 PP amp

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Joined 2004
A friend of mine has build the attached amp from SDS labs .
But it doesn't work. :bawling:
The outputs of the phase splitter are too much different! :eek: Measurements with voltmeter saw as that we have the same voltage at the grid and at the cathode of the phase splitter.
Not the desired 2V that are needed for bias.But around 100mV difference!
An other strange thing is that the first tube works with 0,5mA! :cannotbe:
After all these I'm thinking that the 4K75 at the cathode of the first stage is too big.What do you say?
Any help?
 

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