I have been borrowing our rehearsal spaces SVT 3 pro whilst i source a decent pre-amp/DI pedal and encountered an issue at our last gig. Mid set it cut out, the power light remained on but the gain/peak light wasn't blinking as if the amp wasn't receiving signal. It seemed to kick back in and out a few times and i eventually finished the gig on a DI box via FOH.
Immediate thoughts were cables but upon setting the amp back up at home with the same cables i was unable to recreate the issue. This leads me to think it may have been an over heating issue (i was unable to crank it at home). However, on opening the amp up i noticed that there was a 12AX7 in place of the 12AU7 so i immediately replaced that. Is there any reason why using the wrong valve here would make it cut out? Could understand it not sounding great but would a wrong valve here cause overheating/cutting out issues?