BTW, Jeff's Sound Values down near San Diego has an MG S1 15DT-S for $525. There shouldn't be any difference between the last 2 generations of this amp. The new one uses the new chassis but its components, sockets, wiring, tubes, etc. are the same.

http://www.jeffssoundvalues.com/Inventory/Preamps.htm

Enjoy the Music. Trust your ears. Laugh at Folks Who Claim to Know it All.