I have never had to push this amp, so no problems. Fri nite I had the Gain & Vol at 2:00 and put other controls at Noon. Using a Mex active Fender 4-string balanced a little toward the neck P/U and vol at under full a tad. Pickups are 1/8" from bottom of strings, set up per Fender specs. The speaker rattled and distorted. Bought it at GC when they came out and got the extended warranty so I may have to see how that works out. Anyway, anybody have any advice other than not purchasing Chinese stuff? Thanks