Here is my collection of Ampex recorders a 350 1/4" 2&4TRACK Play,440B/C 1/4" 2&4 TRACK Play,MR70 1/4" 2TRACK,MR70 1/2" 2 TRACK,MR70 1/2" 4 TRACK,MR70 1/4" Transport. I am currently restoring the MR70'S.The 350 is mated to a 440C transport using low impedance transformers.The 440B electronics...