I hope one of you amp gurus out there can help me with this. I recently bought a new Princeton with a Celestion G12-65 speaker. After about 45 minutes of playing, the volume of the amp suddenly drops and it seems to me the tone gets thinner. What would cause this? I should add that I accidentally left the amp running for 24 hours shortly after I got it. Did I damage something? I've had the amp for about 3 months. Thanks.