I recently obtained a Revox G36 reel to reel that started life in a 50hz, 240 VAC environment. The machine came with a 120 to 240 volt step up transformer and old recordings made on the machine appeared to play back at the correct speed using the transformer. I'd prefer not to use the large transformer so I set up the machine to run in its 110 volt setting. The problem is that running in the 110 volt setting, the machine is recording and playing back way too fast. This was verified by playing back a recent Revox recorded tape on a different, fully calibrated machine. I have to assume that plugging a step up transformer into a 60hz 110 volt power source would yield 240 volt, 60hz power which leads to several questions. Would a 60hz power source cause a 50hz motor to run way fast? Will I need a different capstan or capstan motor for a 110 volts? Should I just blow off the idea of not using the power supply and if so, why would the machine run at the correct speed on 240 volts or the wrong speed on 110 volts? Any input about this would be greatly appreciated. Geoffrey
From the manual there are different part numbers for the 50hz and the 60hz machines for the capstan assembly. The motors are 6/12 pole motors for the different speeds.
Full text of "Revox g36 service manual"
Full text of "Revox g36 service manual"
A 50hz motor will run faster on 60hz power. If you record and play back it will sound ok. Prerecorded tapes recorded at the correct speed will not sound right. The manual has a test for correct speed.
Since the capstan motor is a synchronous motor the speed is depented from the frequency so it runs to fast , finding a 60hz capstanshaft is not easy .
you can also use a powersupply for 240-50hz with variable freq.so you can adjust the speed since I found they are not running at the exact speed.
As I think I indirectly mentioned, I do have a 120 to 240 supply but I'd be really surprised if is capable of providing a 50hz output. The machine appeared to run correctly from the supply however I have yet to make a new recording to verify this. One my agenda for the week is to do just that. I'll keep you posted and thank you. Geoffrey