• 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.

Copland CTA 405 bias adjustment

Need help figuring out bias adjustment procedures for vacuum tube amplifier.
A technician told me to check the bias adjustment every 6 months….. problem is I have absolutely no idea how to do it. Furthermore, they charge an arm and a leg every time I bring the amp in.
Any help would be kindly appropriated.