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turntable speed controller

HiFi, LoFi, Tubes, Transistors, ICs, Commercial, DIY

turntable speed controller

Postby huddslad » Thu Oct 16, 2014 7:34 am

Hi I have a AR legend turntable that has manual speed control. This involves taking the platter of and manual putting the belt onto the appropriate pulley which is a pain the neck.
The motor runs on standard 240V ac mains. I have been looking for a speed controller that I can use to change the speed electronically but cant find one. Does anyone know of one, or has built one. I could change the motor to a 24V AC version. Has elektor published one.

Can Anyone help.

Thanks
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Re: turntable speed controller

Postby justin thyme » Sun Oct 19, 2014 8:41 pm

I would have thought that the speed of the AC motor is dictated by the mains frequency, not the voltage. If so, then you'd need a circuit that can change the frequency!
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Re: turntable speed controller

Postby ahmedzg » Wed Dec 10, 2014 5:23 pm

It's very complicated to control AC motor by electronics , it made of mechanical parts usually
So I think you have to use a Dc motor 12 or 24 volt with internal or external dc regulator
By altering the motor shaft pulley' diameter for the whole range and the regulator control as a fine coarse adjustment , You'll get good result
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Simple turntable speed controller

Postby electrosmoke » Thu Mar 26, 2015 10:52 am

It is not so difficult to control the speed of a synchronous turntable motor - all you need is a stable sinewave oscillator hooked to a power amp feeding the secondary winding of a small mains transformer - which should provide the "artificial" mains voltage of 230 V (or whatever) at about 4...5 W feeding the truntable motor with a constant voltage at variable frequency, thus controlling the speed.

I remember an article in Wireless World ages ago on a speed controller for a dancing studio turntable based on this idea - it used a PLL-IC (NE567?) as a generator.
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Re: turntable speed controller

Postby officina tron-audio » Wed Apr 08, 2015 2:26 pm

oups sorry
User avatar
officina tron-audio
 
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Re: Simple turntable speed controller

Postby gerardoS » Thu Apr 12, 2018 11:31 am

electrosmoke wrote:It is not so difficult to control the speed of a synchronous turntable motor - all you need is a stable sinewave oscillator hooked to a power amp feeding the secondary winding of a small mains transformer - which should provide the "artificial" mains voltage of 230 V (or whatever) at about 4...5 W feeding the truntable motor with a constant voltage at variable frequency, thus controlling the speed.

I remember an article in Wireless World ages ago on a speed controller for a dancing studio turntable based on this idea - it used a PLL-IC (NE567?) as a generator.

Thank you for the information, you've been very helpful. Remember the Wireless World article? I'd like to read it.
Greetings.
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