• 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.

Troubble shooting help please.....

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The plate voltages on the ECC99 are reasonable- the way this circuit is set up, there's roughly 6mA through each section and that's more or less what you're getting. The fact that the "zero bias" issue is common to both channels makes me a bit suspicious that your voltmeter may be perturbing the measurement. As it sits now, with the OP stage biasing working, does the amp pass signals without distortion?

Hi Sy

I have a digital multimeter, new.

I hooked up the amp today and I have distorsion in both channels, weak bubbly sound.

Just a thought, what would be the result of putting the ECC99´s under to much stress. What would the result be when a ECC99 in this configuration is worn out? Would it in fact react the way my tubes are?

Cheers
 
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