For some reason the stars aligned last week and I snagged an AMP BH-260 & a 420 for a total of $200! The 260 looks rode hard and put away wet, but works fine. The 420 looks better & works but, looking under the hood, seems to have been fiddled with. Anyone have the manual & schematic for either one? I can reverse engineer them but, I'd rather have the orig. docs to stare at and make sure some solder monkey didn't get creative. These are the polar opposite from my Trace MkV pre/Bryston 4B rack. Way cool. I just wanted something small for duo & trio gigs. I tried the 260 into an Acme B2 for a jazz quartet gig. Dang it's loud. The sax player kept asking me to turn down. Cool. Now if I can just get my hands on the KB-400 I found I'll have the set. Had to tell someone.