DIY TURNTABLE : ideas and comments.

[Hiten]

Some interesting reading from page 7 onwards...
So How's it done? - Page 7 - diyAudio
Regards

 

[omishra]

So we need sinewave oscillator and amplifier. so will require more electronics which I am trying to avoid. How about UPS inverter (the small ones with 20/25 min. backup) I presume they must be having voltage regulation and oscillator (not by capacitors) for steady frequency. If possible we can supply regulated 12 V DC supply (as they get from lead batteries). what say ??? once voltage and fq. is stabilised I can use AC motor without worrying about major speed drifts.

That's long way, but sinewave generators are not cheap and bulky for required power.

Sorry for repeating wouldn't brushless DC motors be easy to control and stabilize as it will only need feedback and voltage regulation. I checked with friend at lamington road. Only DC motors they have are for aeromodelling and robotics from Rs. 500 onwards.
Thanks again

These are simplest to control. And I am not sure why are you are worried about drift in speed. Even PS or motor temperature can change current and speed of any motor AC/DC. Only compensation from feedback circuit can do the trick to mitigating error in speed. (this is like strobe circuit etc.)

 

[dillihifi]

Our frequency does vary a little bit in either way. You can see the current frequency at WESTERN REGIONAL LOAD DESPATCH CENTRE

 

[Hiten]

Thanks omi. You have been of great help. So drive system is narrowed down to.
1) AC motor (Just because it is very well made) with tapered pulley (For accurate speed control) connected directly to AC line.
2) DC motor with feedback and regulation.
Thanks again will look for DC motors. Meanwhile can you post some link of pic of circuit or module to control DC motors.
@dillihifi - wow ! great link. Have bookmarked it. will be watching fq. change at various intervals. A very little change is ok. 0.5% change in fq. results in 0.33 rpm loss. I think its ok.
regards

 

[Hiten]

Just for the info.
I checked the frequency from the link given by dillihifi. Took five reading yesterday evening, today morning and afternoon. Took the average and fluctuation is approx 0.20 hz bothways. which me thinks is negligible.

So rejoice ye vintage synchronous motor turntable owners
regds.

 

[omishra]

So whats the plan? AC/DC motor?

 

[dillihifi]

You also can check the frequency graph for the day from the following link

NRLDC

 

[Hiten]

So whats the plan? AC/DC motor?

Will look for DC motor with feedback module first. If not easily available I already have garrard motor.

You also can check the frequency graph for the day from the following link
NRLDC

Thanks
Regards

 

[omishra]

I am thinking of this circuit which takes input from rotation, (like inside the ball tracking mouse has).

In fact salvage parts from old mouse and some new for this. Power handling capabilities will be added, because that OPAMP can't drive motor effectively. So we will give it a helping hand by putting some MOSFET inline.

I will design something using this reference.

BTW, DC motor under consideration is brush less or with brush?

 

[Hiten]

From what I have read brushless are very much preferred. Threre were few motors available on ebay with what looks like feed back and control
Pioneer PL 220 Motor, Pitch Control, Strobe Assembly-Vintage Turntable | eBay
but am reluctant as they may be non working and I don't understand circuits to repair them. Lets see...

 

[sachu888]

Hiten,
This is for you Homemade Turntable... - AudioKarma.org Home Audio Stereo Discussion Forums

Regards,
Sachin

 

[Hiten]

Sorry for late reply Sachin. Things are little hectic.
Thanks for the link. That diy is neat, wood plinth looks beautiful. Worth considering.
Regards

 

[Hiten]

In overenthusiasm bought two turntables. One is Garrard fully automatic. Idler Drive. Other is Sansui Direct drive. Took a peak inside Sansui. It has Frequency generation servo Direct Drive motor.

The Garrard.

Fully automatic functions are not working, so considering restoration.
I know times have changed. But that 'Pink' Plinth is definite NO NO. First thing I will do is destroy the plinth.

Sansui DA-P500

Regards

 

[jls001]

Hiten,
This is for you Homemade Turntable... - AudioKarma.org Home Audio Stereo Discussion Forums

Man, that guy's got some skills with woodworking.

 

[jls001]

@Hiten: I am assuming you are opting for the DC motor. Is the drive mode finalised (as in is it gonna be a direct drive, belt, idler, a hybrid, or your new invention)? I think the solid wood plinth pointed out by Sachin looks really awesome, and do-able.

 

[Hiten]

Yes joshua DC motor is what I want. but so far have not found brushless DC motor. I bought above two turntable to salvage some parts, but no luck there either. Garrard has massive spindle with bush with ball bearings not good for quality TT. DD motor in Sansui is good though.
Yes wood plinth looks great. But I was thinking single heavy Aluminium base for spindle and tonearm. Motor + rest of the stuff on MDF. But that would be thinking ahead before finalising motor, spindle and speed control stuff. will decide soon. Also thinking of restoring garrard. So many things to do.
Regards

 

[grubyhalo]

Yes joshua DC motor is what I want. but so far have not found brushless DC motor. I bought above two turntable to salvage some parts, but no luck there either. Garrard has massive spindle with bush with ball bearings not good for quality TT. DD motor in Sansui is good though.
Yes wood plinth looks great. But I was thinking single heavy Aluminium base for spindle and tonearm. Motor + rest of the stuff on MDF. But that would be thinking ahead before finalising motor, spindle and speed control stuff. will decide soon. Also thinking of restoring garrard. So many things to do.
Regards

Do a search on DIYA for "mark kelly dc motor", you would get a lot of informational threads to help you form an idea about all aspects of a TT, including this gem...

 

[Hiten]

Thanks gruby, but I can not afford it. It costs around Rs. 10/15,000. A High quality brand new turntable spindle and bearing will cost aprx. Rs. 8,000.
Now some vintage TTs have fantastic low rumble figures. So it only makes sense to use them. Same for the motor. Hope you understand.
Regards

 

[sachu888]

Thanks gruby, but I can not afford it. It costs around Rs. 10/15,000. A High quality brand new turntable spindle and bearing will cost aprx. Rs. 8,000.
Now some vintage TTs have fantastic low rumble figures. So it only makes sense to use them. Same for the motor. Hope you understand.
Regards

Hiten,
Did you see this Homemade Turntable... - AudioKarma.org Home Audio Stereo Discussion Forums
He has completed his DIY TT.I will definitely try this in near future.
A video DIY Turntable - SME 3009 Tonearm, NAD Model 90 Vintage Hifi Setup - YouTube

Regards,
Sachin

 

[Hiten]

yes bro,
I saw it when you first mentioned it. DoomRider is an artist.
Regards