Garymac

Hi all - I'd really appreciate any insight anyone has on this. Yesterday during rehearsal my Ampeg SVT started intermittently dropping volume, with mild distortion and general crackling. It wasn't constant or consistent. The setup was Fender precision straight into the amp and 4X10 cab. I changed the instrument lead - no change. There was another bass amp at the venue - plugged into that - same thing! So now Im thinking it's maybe a bad solder joint or pot on the guitar - it is over 50 years old! So the guitar player then plugged into my amp - and the same thing - crackling, etc intermittently. I packed up, came home, set up, and switched on. No issue - there was a little bit of crackling when I adjusted the gain but I think that's just a pot that needs contact cleaner. No issues at all whilst playing and I did so for around 30 minutes without issue. So for me, all the evidence points to some sort of issue with the power at the venue. But I've never ever come across anything like this before. Has anyone else on here any further insights or similar experience?