epiphone valve standard squeal, please help

[pana]

The amp squeals terribly when the volume knob is beyond 1:00. I tried replacing the power tubes - no change. If i unplug the speaker and turn the voume up I can hear a very quiet squeal like the one that comes through the speaker.

 

Any advice?

[Eracer_Team]

I don't own one but its a tube amp, never remove your speaker and power it on if you'd like your output transformer to survive.

Some are very lucky when they do, most are not.

maybe Gil will chime in here, I think he owned one.