My latest DIY TT project

[Thesoundmen]

Hi all,

After reading many logs of people their DIY TT projects, I thought its time to start my own.

The bearing is already in the concept stage and I have a drawing of that to.

The only thing I'm struggling with is what sort of motor AC / DC and what sort of controller.

The platter will weigh 16 kilo or 35,2 lbs.

I have made some 3D drawing in Google SK :







And the bearing :



Comments, suggestions all are welcome.

[Greg M]

Good luck!
I'll be watching, as I am at about the same place as you in making a TT.

[Thesoundmen]

Are their any people who can help with the motor problem.

Which is the way to go AC or DC

an what are possible ways of controlling the motor ?

[Leon08]

I think the most simple option is to take the motor and controller from some other turntable.

[Greg M]

Originally Posted by Thesoundmen

Are their any people who can help with the motor problem.

Which is the way to go AC or DC

an what are possible ways of controlling the motor ?

One method used by amateur astronomers (on their telescope mounts) is to use a synchronous motor controlled by a homemade controller which alters the Hz to correct for tracking errors (when doing astrophotography).

You can find these circuits in back issues of magazines like Sky & Telescope

Just an idea

[ReinoutdV]

Good evening Matthias,

we already had some conversation in Dutch....which is not understandable for all users...so i'll repeat it in short.

I have a serious oversized turntable platter (diameter 50 cm !; 17 kg) and had the same problem as you: the motor.

There are 2 options for this:
- or using a larger motor which is "dominant" over the turntable platter. Logical options are the motors from reel-to-reel tapedecks. Pabst made some really really nice stable motors. These motors have serious torque; they will control the turntable platter with ease. The challenge for this solution is the motor-control. For this you must make a quite complex engine-control.
- or using a quite light motor. Now the turntable platter is "dominant". The motor can be equiped with a rather simple PLL-control and if it runs.....the platter itself is in the lead.

For my TT-platter i opted for the second solution: the light motor. Of course this still has to be a nice stable motor and there are options enough: maxxon, airpax, pabst, premotec ....but i found a funny motor in the former DDR. This is used for tapedecks. It is less then a Watt but it can bring the platter up to speed. This takes time so i help a little...... But when it runs...it runs smoothly/quitly and shockingly stable.

May i suggest to read: krishu.de PLL-Antrieb

My biggest challenge was the building of my own tonearm. A 50 cm platter is fantastic stable (the weigth distribution is far better than a thicker/smaller platter of the same weigth)....but there are very few commercial tonearms available. So i build my own 17.5" arm; and it works like a charm. In the meantime i found ways to improve ths; so i got my Christmas-project already planned.

Back to the motor. Adding a flywheel is totally different. Now you must skip the options for a ligth motor. This will never get a flywheel up to speed which is connected/attached to the platter itself. This means that your stuck to a strong/high torque motor. So you need some serious engine control. If you have the knowledge to do that...fantastic. Remember that making a flywheel contraption is evectively making 2 turntables connected. My suggestion: start with the turntable/motor. If you're not content with the speed stability you can always ad a flywheel later. Again a serious cost driver as the flywheel is the energy reservoir for the turntable platter. So if your platter weighs in at 16 kgs.....

My 17 kgs platter is stable. I have a funny stroboscope and it does 33 1/3 EXACTLY and CONTINIOUSLY. Adding the turntable weigth, stroboscope, vinyl, cartridge.....is simply ignored.....the pll circuit in the small motor simply gives some more and the stroboscope indicates a stable 33 1/3 rpm.

Succes with the building effort. It took me some time and i can only say: well worth the effort !

Greetings from the netherlands,
Reinout
(added some pictures of my contraption. Remember....it is a LP you see...not a small single)

[Thesoundmen]

Originally Posted by ReinoutdV

Good evening Matthias,

we already had some conversation in Dutch....which is not understandable for all users...so i'll repeat it in short.

I have a serious oversized turntable platter (diameter 50 cm !; 17 kg) and had the same problem as you: the motor.

There are 2 options for this:
- or using a larger motor which is "dominant" over the turntable platter. Logical options are the motors from reel-to-reel tapedecks. Pabst made some really really nice stable motors. These motors have serious torque; they will control the turntable platter with ease. The challenge for this solution is the motor-control. For this you must make a quite complex engine-control.
- or using a quite light motor. Now the turntable platter is "dominant". The motor can be equiped with a rather simple PLL-control and if it runs.....the platter itself is in the lead.

For my TT-platter i opted for the second solution: the light motor. Of course this still has to be a nice stable motor and there are options enough: maxxon, airpax, pabst, premotec ....but i found a funny motor in the former DDR. This is used for tapedecks. It is less then a Watt but it can bring the platter up to speed. This takes time so i help a little...... But when it runs...it runs smoothly/quitly and shockingly stable.

May i suggest to read: krishu.de PLL-Antrieb

My biggest challenge was the building of my own tonearm. A 50 cm platter is fantastic stable (the weigth distribution is far better than a thicker/smaller platter of the same weigth)....but there are very few commercial tonearms available. So i build my own 17.5" arm; and it works like a charm. In the meantime i found ways to improve ths; so i got my Christmas-project already planned.

Back to the motor. Adding a flywheel is totally different. Now you must skip the options for a ligth motor. This will never get a flywheel up to speed which is connected/attached to the platter itself. This means that your stuck to a strong/high torque motor. So you need some serious engine control. If you have the knowledge to do that...fantastic. Remember that making a flywheel contraption is evectively making 2 turntables connected. My suggestion: start with the turntable/motor. If you're not content with the speed stability you can always ad a flywheel later. Again a serious cost driver as the flywheel is the energy reservoir for the turntable platter. So if your platter weighs in at 16 kgs.....

My 17 kgs platter is stable. I have a funny stroboscope and it does 33 1/3 EXACTLY and CONTINIOUSLY. Adding the turntable weigth, stroboscope, vinyl, cartridge.....is simply ignored.....the pll circuit in the small motor simply gives some more and the stroboscope indicates a stable 33 1/3 rpm.

Succes with the building effort. It took me some time and i can only say: well worth the effort !

Greetings from the netherlands,
Reinout
(added some pictures of my contraption. Remember....it is a LP you see...not a small single)

Hi Reinout,

Thank you very much for your advice .

I will go with your way without the flywheel it does sound the best option.

I will see how that works out and maybe some time later I make a second motor assembly.

PS : Is that a record clamp with LED ?

Matthias

[triocat]

has your bearing got an oil reservoir?

[Thesoundmen]

Originally Posted by triocat

has your bearing got an oil reservoir?

Yes, but the drawing is not the final design I am working on a new version.

[Thesoundmen]

My latest version of the bearing with a Delrin plate inside, also adjusted the size of the ceramic ball.