Magnavox/Collaro Micromatic Changer Hertz
 

I scored a sweet midcentury Magnavox console here in Spain that had been imported in the early 1960s. It has the same Collaro-made Micromatic changer that all the Magnavoxes had back then. I've got the tuner, multiplex decoder, and power amp all repaired and recapped, and sounding great, and have started on the changer.

After cleaning and lubing, and adjusting the setdown screw, it's working smoothly. There is, however, one serious problem: the changer was sold in the United States and the motor was designed for 60Hz mains power, so here in Europe it runs around 20% slow.

Googling around turns up a few suggestions about using one of those cheap "pure sine wave" inverters to power it, but those aren't really a sine wave and cause horrible noise and overheating in the motor.

So I'm thinking about a possible solution, and wonder if I can get some of the more knowledgeable folks here to give me a reality check or alternative. My idea is to combine a cheap chinese frequency generator board with a cheap chinese PWM audio amplifier board to drive a 12V:120V power transformer connected in reverse.

If I'm calculating right, 20W into 8 ohms should give me the 12V I need of a 60Hz sine wave, to then be stepped up by the transformer and yield 120V. I'll still have to build a power supply for the two boards.

What am I missing? Or is there a simpler way? I get that I could build a 60Hz oscillator out of a few parts but frankly for 3 bucks I'm inclined to go with the digital one.

Find a UK market Collaro changer which is built for 50 Hertz /220 volts and be done with the issue. The 1960's models will work beautifully (pre 1967 models best, the Conquest is nice). Drop in, plug and play. Serviced well, end of speed problems.

Kent is right on the money. While it would be possible to make it work in any number of ways, simply replacing either the whole player, or just the motor with a UK market one is the elegant way to go, and probably easier than you think since these things were made in massive quantities.