Any firms that do mod's to amplifiers?

I know of a couple of companies that mod DACs and source components but only one that, for certain, mods amplifiers - Musical Concepts (www.musicalconcepts.com). I have never used their services so cannot comment on their reliability or quality. Dan at ModWright is becoming a highly regarded expert at modding eletronic components. At the moment the only official mods, according to the website (www.modwright.com), are source components. But you might give him a try anyway.

Musical Design www.musicaldesign.com

Stan Warren will do amplifier mods also.

Check out The Great Northern Sound Company at http://www.greatnorthernsound.com/home.htm

Andy Bartha in Davie Florida has done several mods for me on different equipment. He builds his own amp and mods just about any others on the market. Go to abaudio.com for more info.