• 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.

MFA MC Reference

MFA MC REFERENCE PREAMP

I have in my system this absolutely fantastic preamplifier !
and good news for you i have the complete documentation !
i can make you a copy and send by postal way if you want.

Probably you can help me ... i replaced the 6922 tube in preamp by others 6922 but ..... in the power supply box there is a big rectifier tube called 9330 from penta laboratories ! impossible to find it , so is it the good reference ? no informations in the documentation .... all schema for preamp box but no details about the last tube i would like to replace .....

and internet site from pentalaboratories.com don't react .....from France ! ( you could try from another location ?)

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