Feedback problem with my preamp

[Atheist]

My ada mp-1 screams like mad on higher volumes.

I never used it on rehearsals before. I tried it few days ago and the sound is great while I play. As soon as I stop it's making feedback.

Can it be because of old tubes?

 

[Brett - K A L I S I A]

Get a noise gate

 

[AdamWathan]

Might be a microphonic tube if it seems abnormally loud. Open up the cavity where the tubes are and turn it on and individually tap each tube with a pencil or something similar. If one of them is microphonic it will SCREAM like a man giving birth through his urethra.

 

[Saculus]

If I remember they have two gain stages and if the first is too high you get some feedback. Try easing back the first gain and upping the second. I'm also looking to trade my MP-1 for a sans amp bass driver if anyone's interested.