I have a SF Vibro Champ. I had it blackfaced by a reliable tech and got a Weber speaker for it which sounds good. There is too much bass. I have to turn the bass control down all the way and put the treble up all the way to get a decent sound. If the bass control is on at all the amp starts to distort when the volume is set on 4. Is this usual for Vibro Champ amps? Is there some additional adjustment to be made? Is it the speaker? Thanks for your input. I play a Pensa SSH strat type guitar through the amp.