I just got a JCM800 4104 a couple weeks ago, great condition along with an 8ohm Hotplate. Being the tone freak that I am, I also swapped out the stock GM12-70 speakers for a pair of GH1230's broken in by Avatar, they call them "Hellatone". Big difference with the speakers alone. I also had the amp re-biased for EL34's. I went with the JJ EL34L's and a high gain set of preamp JJ's from Eurotubes. I'm still messing around with the preamp tubes but I keep coming back to the JJ's. Finally, my amp is not here now because I was missing one thing for my Echoplex, an FX Loop. I ended up sending the chasis to my buddy in CA, he owns two JCM800's and 2 JMP's and had all his FX Loops installed by his tech out there. He swears that the circuit this guy uses is as invisible as it gets. His recordings with the loop sound awesome. I can't wait to get it back so I can try out my "Cold Sweat/Trilogy" Guitar, that will be done this weekend!