• 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.

TAC TAC noise in high gain mode

Hello,
i've made several tube amps, with a clean and a dirty channel, and when in high gain, there is a TAC TAC noise, it's dry and trebble sensitive, a TAC every 1.5 / 2 secondes. I used different diodes for the bridge, 1N4007 or faster diodes (UF something).
It gets louder with the gain and trebble...
ANy idea to understand, and maybe solve it?
Many thanks
 
If the noise is always present, independent of the circuit, then it must be from something
in your house, or nearby anyway. As a last resort, turn off the preamp too.
Don't forget LED lights, toys, appliances, etc.

However, if the tone controls affect the noise level, then it must be in the preamp.
To rule out the power amp, add shorting pugs to its inputs and see if the noise is gone.
 
Last edited: