Speaker chirps at full volume and gain

[keith]

This 36 watt amp is stable -until the MV and TMB gain are all the way up-. Then, when hitting any note or cord, the speaker will chirp. This is only when the note/cord is actually played, its not a continuous chirp. The tubes have been swapped, the speaker is a new Private Jack(50W). The TMB gain pot is a 1 meg rather than the 500k. Ideas?

Thankyou,
Keith

[phsyconoodler]

Since you don't normally play with the gain and volume all the way up,it may be that you are way overdriving the power tubes and there is an oscillation at full song.
You might have to put in a larger cathode bypass resistor or put the 500k pot in where you have the 1meg pot.The gain is probably too high with the 1meg in there.

Fancy that,I'm Keith too!

[keith]

Thankyou, for the reply.

you don't normally play with the gain and volume all the way up

I was trying to determine if there were any problems. I'm not sure if this is really a problem, or if I'm operating the tubes/circuit outside of the design parameters.

and there is an oscillation

I was told by another, that this type of oscillation can be very difficult to troubleshoot.

Thankyou,
Keith

[JohnnyCrash]

Check each solder on your Volume/Gain and Master Volume control through to the resistors/caps and tube sockets (also check the TMB's solders)...

I've had chirping due to a cold solder joint and/or a poor connection before on a Volume pot and the Volume's path through the circuit.

Obviously cold solder joints can also make crackle/pop noises as well... but the chirping caught me off guard and frustrated the heck out of me!