Question ?
I have been offered a Pro-Ject Speedbox that outputs 16 volts ac at frequencies for 33 or 45 rpm on a synchronous motor.
Is it possible to feed this output through a transformer to provide around 100 volts ac so that I can use it to power my Thorens turntable.
Yes I know Pro-Ject have a model that has this output but that is not the model I have been offered.
A transformer with around x 6 step up would seem a possibility.
I have been offered a Pro-Ject Speedbox that outputs 16 volts ac at frequencies for 33 or 45 rpm on a synchronous motor.
Is it possible to feed this output through a transformer to provide around 100 volts ac so that I can use it to power my Thorens turntable.
Yes I know Pro-Ject have a model that has this output but that is not the model I have been offered.
A transformer with around x 6 step up would seem a possibility.
20 or 30 years ago I experimented with a generated power signal to feed the Thorens motor in my TD150.
I know from the cap/resistor that my 240Vac version actually used 120Vac as the motor supply.
I bought a cheap pre-built 50W amplifier and used a small back to front mains transformer (maybe around 25VA) to take the power amp output up to ~120Vac
I could play with the sensitivity control on the amplifier input to change the transformer output voltage.
The motor would run nicely anywhere from ~90Vac to ~130Vac.
But it would not start from 90Vac. I can't recall the minimum starting voltage, but I think it was around 105Vac. So I listened with 110Vac to 125Vac. I couldn't hear any differences over that range.
The intention was to build a crystal reference signal for the two frequencies needed for 33.3333 and 45 rpm. (cheap TV crystals divided down exactly to the the required frequencies), i.e. change the oscillator frequency to change the TT speed. I still have them in stock, but I never finished that project.
I know from the cap/resistor that my 240Vac version actually used 120Vac as the motor supply.
I bought a cheap pre-built 50W amplifier and used a small back to front mains transformer (maybe around 25VA) to take the power amp output up to ~120Vac
I could play with the sensitivity control on the amplifier input to change the transformer output voltage.
The motor would run nicely anywhere from ~90Vac to ~130Vac.
But it would not start from 90Vac. I can't recall the minimum starting voltage, but I think it was around 105Vac. So I listened with 110Vac to 125Vac. I couldn't hear any differences over that range.
The intention was to build a crystal reference signal for the two frequencies needed for 33.3333 and 45 rpm. (cheap TV crystals divided down exactly to the the required frequencies), i.e. change the oscillator frequency to change the TT speed. I still have them in stock, but I never finished that project.
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