Thanks for the C37 rack info. I had been using a Rubbermade rolling cart that fits almost perfect for C37 on the top section and a shelf underneath to place a PS Audio Power Re-generator P1000 with the Multiwave II option for going from 60Hz input AC power to 50Hz output power with me adding a 110V to 220V step up transformer inside the P1000 to feed my European C37 at 220VAC 50Hz. I can change the output frequencies in 1 Hz increment and it's been an excellent remedy for varispeed needs with some of the old tapes that were recorded with slight variance in speeds.
The C37 was originally owned by RCA in NYC and they tinkered with a few things. The machine uses 4 relays for NAB and CCIR and specialized EQ. All the caps are German Roderstein / Vishay, resistors are all Low Noise metal film 2%.. I am trying to keep it as stock as possible.
I was talking to my tech and found out some real interesting improvements that can be made to the record and playback preamps. So I told him to do his magic....exciting. There are several impediments in the signal path on all the preamp designs which are now 60 years old. So the result will be a much cleaner and more powerful signal which will enhance the sound of tube compliment, which is excellent and with the improved EQ, bias levels.
Here's the record preamps with swapped out transformers replacing the inadequate Beyers. Just one of the upgrades Dan is doing for me. These transformers will make a overall big difference and these had excellent specs.
The sound is really amazing
If you listen modern music the bass is no good like A80 and other less old and high is little roll off vs A80 and A816 and 820
but for jazz and classic music from mid bass to mid high the sound is magic,very natural,dynamic and impressive
The price for rack i don't remember but tomorrow i ask to Fabio Liberatore,owner of therecorderman,or you can send mail to him