• 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.

Replacing 6DJ8 with 6GM8

I've got a surplus stash of 6GM8 / ECC86 tubes and thought a re-working of the attached circuit might make a decent junk box linestage.

Can anyone assist with changing resistor & capacitor values if we were to have 24vDC B+ and 6.3v DC H+?

John Broske posted this scheme for reducing the Aikido circuit gain. I've use it to good effect.


The two 200k resistors are effectively in parallel and equal 100k of resistance, which then forms a two-resistor voltage divider with the 124k resistor. The result is a gain 4 (+12dB) with 6SN7s. If we use a 6DJ8 instead, we will need to impose greater attenuation.
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