I had mine slightly refurbished by a repairman friend. He did change one regulator in the PSU and clean all the pots with compressed air then lighter fluid and finally some lithium grease. Especially the mix pot was causing problems and constant crackles in the tone. It was a super quick job (he did it in front of me) and it really brought the thing back to life ! Mine sounds super fine, smooth and clean. I put a modified Ernie Ball in the exp pedal input, instant Whammy !!! I find it more musical sounding than most newer pitch shift algos. The regen pot is the source of crazy light saber noises and such. Lots of fun.