Tube power supply for turntable

[julienlebas]

Thanks Mark. Any recommendations for a fairly simple circuit to control a Maxon 110189 motor? My electronic skills are quite limited and although I received from you and others the article and circuit for your control circuit, I wouldn't mind starting with something a bit simpler. Thanks

 

[Mark Kelly]

The app note circuit Kevin postd is about as simple as possible without huge compromises in performance.

 

[kenneth]

Controler

This is the ready built controler. Not yet installed on my turntable, but works fine so far. I will post more pics later when my turntable is ready for a test spin.

 

[julienlebas]

Thanks Kenneth for posting these. I am in the process of building it right now. Just one question: did you use an external symmetrical power supply? Or is it part of the board?

 

[Mark Kelly]

Relevant to the title if not the rest of the thread's content, I just found this phot on my hard drive.

It's a PP KT88 power supply for a Garrard 301. I built it about 15 years ago and ran it for a while before going on to other things. Can't remember what happened to it, probably pulled it apart because it was taking up space.

 

[kenneth]

I am using a external +/-24v supply with +/-9v regulators on the board.

 

[barrymagrec]

View attachment 292367

Relevant to the title if not the rest of the thread's content, I just found this phot on my hard drive.

It's a PP KT88 power supply for a Garrard 301. I built it about 15 years ago and ran it for a while before going on to other things. Can't remember what happened to it, probably pulled it apart because it was taking up space.

Puts me in mind of the Valradio Osc / amps that they used to make to drive synchronous capstan motors on tape machines to give variable pitch. four 807s if I remember.

 

[kenneth]

Reference suly

The voltages I quoted are for the supplies.. You will need a separate reference which could very easily be derived from one of the supplies, I'd recommend an LM385-1.2V reference, a 10T pot for each speed, and a switch to select speed. The LM385 is a shunt reference and can be run off of the 9V supply using a series resistor..

Hello! should the LM385-1.2v reference have a negative (-9v) supply. My controler works but have reversed polarity where the motor is connected.
Thanks, Kenneth