I picked up a cheap but mint condition Marshall MA50H head. I've read up on them and understand that it's probably biased cold from the factory and rebiasing it can warm it up, in at least two ways. Since I'm averse to doing any heavy mods on either of my classic JMPs, I'm thinking that modding this entry level amp (Entry level for a "real tube Marshall", anyway...) is something I'd consider doing. The basic goal: A browner sound. It has plenty of gain already. Making it warmer and less fizzy at lower volumes would at least be very much appreciated. Is there much of a library of mods for this model? Or have people decided it's not worth doing many mods for?