The guy I sold it to did this to it after he got it.
"I did 2-20volt zeners for a lighter symetrical clip and then a 12volt 15volt for a little asymetrical clipping. I boost it alittle just because I like a little OD boost. The amp rips and has a Jose vibe to it."
I thought it sounded pretty good, but not really my thing. I bought that amp to flip, I think I paid $350 for it.