Thats happend to me many times its definetly the v1 Preamp tube just swap it for a diffrent one or make sure its pushed in all the way.

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Figured i would post my gear since im new

Guitars - Gibson SG custom aftermarket pickups
- Gibson LP custom
- 1976 Gretsch corvette
Amp - Mesa Dual Rectifier Solo head w rectifier cabinet

Effects - MXR phase 90,BOSS DD6 , BOSS BF2