Hi Cowabbi,
I had a look in my old akai X201D reel to reel tape deck which has a 50/60 hz option.
besides 100/110/120/200/220/240 volts ac in.
There is a lever which actually changes the belt to the different size pulleys on the main motor and flywheel drive to allowe for that. This deck has an ac motor for the capstan drive and two directly driven spindles for the reels. The extra loading on the motor is minimal with the frequency change.
