played a four hour gig last night with my Reeves Custom 12. We mic everything so the amp was at about noon to start for clean. Through the first set and most of the second, the tone was as I had set it ... clean with the slightest bit of hair. By the third set, there was noticeably more drive and grind to the tone. It sounded good, but I had to dial back on my Strat volume knob a touch to clean it up a bit. Good news was I could roll back up and get mild crunch tones and just flip on the OCD for leads. Question is do others hear experience the same type of change in tone throughout the course of a night's playing? Is it the tubes heating up to a certain point?