SOTA Turntable and 50 Hz power

[cricfansd]

To the Turntable gurus in India,
I am in the process of moving to Bangalore from US and I am shipping my Sota Sapphire turntable. I have a major doubt which may determine whether I finally bring it to Bangalore. The sapphire models are driven through AC synchronous motors which are dependent on the supply frequency. The question then becomes whether the speed control becomes difficult with 50 Hz frequency as the deviation from 60 Hz frequency is around 20%. I can compensate it by changing my mains to 100 V from 120V using a variac but before I do that I wanted to get an opinion from the gurus here. Otherwise the Table goes on Audiogon.
Changing the motor etc on the SOTA is quite expensive.

 

[reignofchaos]

Normally you only need to change a pulley for 50->60Hz conversion if the motor accepts dual voltage. Best is to contact the manufacturer.

 

[marantzcdfan]

suggest you start by trying the step-down transformer, take a closer look once you've tried that.

 

[cricfansd]

Just a reference a new motor and power supply costs around $1K for SOTA.

 

[sachu888]

Just a reference a new motor and power supply costs around $1K for SOTA.

You will need a 50hz pulley for accurate speed.You can calculate pulley size for 33/45 Rpm if you know the drive platter size and motor RPM

Here is an example of how to calculate pulley diameter.
This shows a 4" diameter subplatter being driven. Keep in mind that you also have to factor in what type of belt you are using.
The example below would be used for a flat belt. If you are using a "grooved" pulley for a string drive or round belt, you have to calculate the groove angle and contact area where the belt is being driven to get an accurate pulley size. I normally use the formula to get me close and then fine-tune the final diameter by measuring actual speed with the pulley on the motor.

Motor speed x motor pulley diameter divided by hub diameter = R.P.M.
Example:
Motor speed = 300 RPM
Hub size = 4.000"
Small pulley = 0.444" (33.3 rpm)
Small pulley = 0.600" (45 rpm)

Source: Diyaudio.com

Regards,
Sachin

 

[pnreddy]

To the Turntable gurus in India,
I am in the process of moving to Bangalore from US and I am shipping my Sota Sapphire turntable. I have a major doubt which may determine whether I finally bring it to Bangalore. The sapphire models are driven through AC synchronous motors which are dependent on the supply frequency. The question then becomes whether the speed control becomes difficult with 50 Hz frequency as the deviation from 60 Hz frequency is around 20%. I can compensate it by changing my mains to 100 V from 120V using a variac but before I do that I wanted to get an opinion from the gurus here. Otherwise the Table goes on Audiogon.
Changing the motor etc on the SOTA is quite expensive.

The Sota web page says that the drive motor is run on DC.

"Due to the low current application, the Electronic Flywheels super-fast and dynamic regulator circuits are able to deliver only pure DC voltage to the motor system."

If this is true you may need only a 220/110 V step down transformer. But it is better to get this clarified with the manufacturer. You could also request them and see if they have a 50 Hz pulley. I hope this helps.

 

[sachu888]

The Sota web page says that the drive motor is run on DC.

"Due to the low current application, the Electronic Flywheels super-fast and dynamic regulator circuits are able to deliver only pure DC voltage to the motor system."

If this is true you may need only a 220/110 V step down transformer. But it is better to get this clarified with the manufacturer. You could also request them and see if they have a 50 Hz pulley. I hope this helps.

Hi,
Sota must have 50hz pulley for your table.

Regards,
Sachin

 

[sachu888]

Sota Sapphire has AC motor

Hi,
Sota Sapphire turntable uses AC motor,so you will need a 50hz pulley.

Regards,
Sachin

 

[cricfansd]

Thanks. Yes I figured that I may need a 50 Hz pulley. I have contacted SOTA, lets see what they say.

 

[cricfansd]

Just a quick rejoinder, according to SOTA , this is a pre 1986 SOTA and it uses DC motor. According to them it should work if the voltage is converted. So SOTA Sapphire comes to Bangalore :yahoo:

 

[sachu888]

Just a quick rejoinder, according to SOTA , this is a pre 1986 SOTA and it uses DC motor. According to them it should work if the voltage is converted. So SOTA Sapphire comes to Bangalore :yahoo:

That's a good news.

Regards,
Sachin

 

[miroflex]

Just a quick rejoinder, according to SOTA , this is a pre 1986 SOTA and it uses DC motor. According to them it should work if the voltage is converted. So SOTA Sapphire comes to Bangalore :yahoo:

Finally, relief from frequency change worries and the joys of American versus British schools of electrical engineering. Faraday, Edison, Tesla et al probably never envisaged such problems would arise in the international movement of electrical equipment. Happy listening in Bangalore!

Regards.