My latest DIY TT project

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
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 :

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


And the bearing :

An externally hosted image should be here but it was not working when we last tested it.


Comments, suggestions all are welcome.
 
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
 
just input for a DIY-TT

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)
 

Attachments

  • IMG_0434.JPG
    IMG_0434.JPG
    54.2 KB · Views: 349
  • IMG_8821.JPG
    IMG_8821.JPG
    70.8 KB · Views: 173
  • IMG_9046.JPG
    IMG_9046.JPG
    58.4 KB · Views: 177
  • motortje 2.jpg
    motortje 2.jpg
    23 KB · Views: 181
  • motortje 3.jpg
    motortje 3.jpg
    29.2 KB · Views: 143
  • motortje 5.JPG
    motortje 5.JPG
    65.2 KB · Views: 126
  • motortje 4.JPG
    motortje 4.JPG
    56.8 KB · Views: 142
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
 
Gyrascope

Good evening again Matthias,

you had a question about my stroboscope annex lp-weigth.

I was looking for a way to SEE the rpm's during play. So the normal stroboscope devices do not work (they are UNDER the vinyl that is playing).
Next option is measuring the speed by a sppedometer. It works.....but has a high degree of uncertainty for you must keep your hand seriously steady as this will inflence the measurement.
Then i saw on an audiofair a turntable-weigth annex stroboscope. It is called the Gyrascope and made by the French company Lys.

This battery powered device flashes with the leds (options for 33 1/3 and 45 rpm) and if the rotation is exactly the chosen setting....the leds look like they are not moving. A very nice device: easy to use. Precise.
As the leds will become a nuisance over the time: simply turn the Gyrascope...still in function a a weigth.

I noted that currently there are more of these devices. One is made by Sutherland (Sutherland Timeline). This produces a laser-point on a wall...if it moves....the turntable does not rotate perfectly 33 1/3 or 45 rpm.
The other is spotted on Ebay; it is from the Far East....no more data available.

This answers the quenstion ?
Reinout
 

Attachments

  • IMG_7549.JPG
    IMG_7549.JPG
    51.5 KB · Views: 232
  • IMG_7556.JPG
    IMG_7556.JPG
    61.4 KB · Views: 230
  • IMG_7559.JPG
    IMG_7559.JPG
    60.5 KB · Views: 221
  • IMG_7562.JPG
    IMG_7562.JPG
    57.2 KB · Views: 224
  • IMG_7708.JPG
    IMG_7708.JPG
    44.2 KB · Views: 222
Good evening again Matthias,

you had a question about my stroboscope annex lp-weigth.

I was looking for a way to SEE the rpm's during play. So the normal stroboscope devices do not work (they are UNDER the vinyl that is playing).
Next option is measuring the speed by a sppedometer. It works.....but has a high degree of uncertainty for you must keep your hand seriously steady as this will inflence the measurement.
Then i saw on an audiofair a turntable-weigth annex stroboscope. It is called the Gyrascope and made by the French company Lys.

This battery powered device flashes with the leds (options for 33 1/3 and 45 rpm) and if the rotation is exactly the chosen setting....the leds look like they are not moving. A very nice device: easy to use. Precise.
As the leds will become a nuisance over the time: simply turn the Gyrascope...still in function a a weigth.

I noted that currently there are more of these devices. One is made by Sutherland (Sutherland Timeline). This produces a laser-point on a wall...if it moves....the turntable does not rotate perfectly 33 1/3 or 45 rpm.
The other is spotted on Ebay; it is from the Far East....no more data available.

This answers the quenstion ?
Reinout
Haha thanks Reinout,

This is something I am certainly going to buy !

For the motor I was looking at Maxon I saw a brush less flat motor there it was a 24V but that not a big issue the fact is you can directly solder to pot meter on the motor to change speed.

Do you now how much torque your has ?

Greetings Matthias
 
Did some more drawing work on the motor unit this time I worked on the inside of the unit. All necessary cabling comes inside the box except for the PSU than. Everything will be covered with one piece of ALU.

The second photo you can see how the engine is mounted on to the disc.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.