Marshall JMP-1 Modded by Voodoo Amps with their coveted Platinum Mod. How can Billy Gibbons, Neal Schon, Phil Collen and more be wrong. Best of the best to make the JMP-1 a Beast! Preamp sounds fantastic and works perfectly. It is missing some screws on the top and back but nothing that affects performance, and can easily be found and replaced. Rack scratches and one of the ears is a little bent. The serial number is 943672651, you can verify the mod on the Voodoo amps website by plugging in the serial number.