Stepper motor behaving strangely

Here's the video of the platter. Sharing with google drive since it does not allow to upload videos.

https://drive.google.com/file/d/1-n4k9CgYBYcuhNz4ye5GB4bPK5SXCWNN/view?usp=drivesdk

The machining is all done by hand (coupling the platter to the motor) so its not perfect. Also its not very evident but the platter is slightly off centre.

I put a styrofoam sheet on the platter to act as a mat - reduce, recycle, reuse! :laughing::laughing:

If you are interested in the audio, please let me know your email ID, I will share the audio privately.

Oh you mean a static electricity collection device.
Ever wonder why they are normally a heavy rubber ?

I'm not sure if the rubber mat is for static but it ensures that there is some grip/isolation between the platter and the record.

Of course I know that we should use a rubber mat, and it will look many times better - but I used it anyways to see if makes any difference to the sound - it does not. So, till I get a mat I shall leave it as it is.

Hi,
If the rubber platter contains carbon, then it will help discharge any static electricity.
Help to keep your vinyl dust free.

Tom... :smiley: :+1: :coffee: :australia:

Oh yes...I wasn't aware of that.

For homemade, the platter spin is decent.
You need to ditch the foam and get a proper mat.

Thank you. Noted regarding the mat.

Proper black rubber contains an ingredient called "carbon black"
Carbon black also has a lot of warnings when by itself but is considered safe when bonded into rubber.

A mat should be proper rubber not one of the newer materials fashioned to simulate rubber eg newer vinyl's or similar.
Quite often you can tell the difference just by picking it up and it should flex (A LOT) and the newer chemical versions are often stiffer.

Yes. I guess even the silicone rubber ones flex a lot...

The main reason for heavy rubber mat is to damp oscillations of the platter (which is normally metal and would ring like a bell otherwise). Not really needed for a wood or fibreboard platter which are much less resonant.

Anti-static isn't much use in a mat unless the vinyl itself is conductive - typically the side being played picks up a lot of static from the stylus friction and the only decent cure for that is a little trailing carbon-fibre brush dangling from the tone arm, or some anti-static coating/spray for the disc itself. Static only builds up on the surfaces of insulators, and it causes two problems: audible clicks/fizz when sparks/corona discharge jump between vinyl and the stylus cantilever, and secondly it attracts dust like crazy.

Still a conductive mat will take off a lot of the charge from the side once you flip the disc over - can't be a bad thing, probably helps dust drop off again.

And heavy rubber lies flat, which is important.

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Yes. Most of my records are very old and have a lot of dust. I have washed them all with mild soapy water and a thorough rinse in running water - gets rid of all dust and static - its not just the stylus or friction that causes static, even the plastic sleeve in which they're stored (I guess its the vinyl (PVC?) with which the records are made is the main factor). I've seen on YouTube some videos about "fixing" scratches with WD40. Any experience with that?

You should really use de-ionized water for this, a film of calcium and magnesium salts from hard water would be bad news for surface noise and the longevity of the diamond stylus.
Vinyl should be stored in paper inner sleeves inside cardboard sleeve/cover. plastic inner sleeves are to be avoided as they are the worst possible scenario for static as just sliding the disc out charges it highly.

Agreed. Better still to use isopropyl alcohol (surgical grade), I guess.

Also, as I had mentioned earlier, I have documented the entire build process and even created a small youtube video of it here:

https://sites.google.com/site/rohitbalkishandubla/direct-drive-turntable

I wish I could link to the sample audio file to show that it actually works, but in the interest of copyright it cannot be done, and I guess everyone will have to take my word for it....or better still build it and see for themselves... :smile:

Ok. I've uploaded a short demo video of the turntable in action on youtube. Do check it out...

https://youtu.be/PN47wAvJ37E

Looks like the pad is causing some wobble.
Quite an achievement though :slight_smile:

Thank you! I The records are a bit warped as well.

Never use solvents on a vinyl disc, that will melt the plastic or at the very least swell it up and/or remove the plasticizers essential for keeping it from getting brittle.

Working surprizingly well, I'd have imaging more motor noise (although I bet its noticable on headphones, which is a demanding test). Balsa wood tonearm? That's probably a good choice acoustically (if a bit fragile).

WOW that is surprisingly good for a cheap turntable.
The sounds has some definite flutter in there but I think you will get around to that with some better materials in your build.

Well done !

:ok_hand:

Tested with headphones as well... I'm happy to announce that there is no motor related noise. Yes there is the usual pops and crackles plus a slight background hum because of the preamp gain - it's there even with the turntable stopped.

Tonearm is made with softboard - its not wood but a kind of paper based board. Very easy to cut and assemble into various shapes. Its strong too once the adhesive sets...