Here's a totally mint jcm800 that originally had that one off mod by Dave Friedman for Reza. It already sounded good with that mod (if you've seen his clip you probably already know this), but it sounds 1000x better now with this V5 mod by Jens Kruse. The V5 mod has a 5 way switch on the back that lets you choose between 5 different modes (hence the name) that get, for the most part, progressively more aggressive as you turn it clockwise. There's also a 3-way toggle switch on the back to choose between different bottom end response and a low and high input on the front. Jens' mods are at least as good as any that I've tried by Friedman, Cameron, or Gower. I'm only selling since I made some pricy guitar purchases lately and need some money back
I just got one from Home Depot, helped me clean up my music room. I had guitar heads all over the place. Good luck to the seller of the amp, I bet it's a great sounding amp.