New Technics SP10 motor controller specification - Page 3

Shaun · 19th June 2008, 06:33 PM

If the source code is available, it would not be a major task to port it over to another chip. One can make allowances for obsolescence by making the controller board separate from the PSU and drivers, etc. So one just needs to make a new controller board with the same electrical interfaces.

However, I've been pondering your idea of not reinventing the wheel (expressed in PM). One would have to replicate the main system blocks using currently available components, so the design effort required should be reduced.

Steerpike · 19th June 2008, 07:46 PM

How much of the original circuit have you 'reverse' engineered so far?

analog_sa · 19th June 2008, 08:30 PM

Quote:

Originally posted by Steerpike
If the software (HEX dump) is free on the WWW, would most (all?) readers have some access to a PIC or EEPROM programmer?

Other than the terminally brain dead, yes. Putting together a programmer on a vero board takes five minutes.

It may be a better idea to publish assembler (or C) as well. It's pretty straightforward to recompile it for a different micro.

Zero Cool · 19th June 2008, 08:44 PM

The SP-10's has some very good noise floor. So whatever controller you build will have to be very sophisticated to be as quiet. ramped pulses, feedback loop for stability etc.

The people that would have the most interest in something like this are archivist's that work with odd variety of disc's. The most important thing would be the pitch control. a very large +/- range would be helpful and it should be adjustable in semitones and cents not % which is about useless. Even if it read out in direct RPM would be better.

Variable speed from 10tpm to 100rpm would be desirable. backwards play at any speed. the ability to control start up and stop speeds. etc.

The controllers for these motors, for any of the technics direct drive motors are pretty well thought out. To duplicate one is no easy task! The hardest part is reducing cogging of the DD motor. the 10's had a -93dB noise floor if memory serves correct where as the 1200's and SP-25, SP-15's had something like -78db

best of luck. let us know how it goes!

Steerpike · 19th June 2008, 09:18 PM

Quote:

will have to be very sophisticated to be as quiet. ramped pulses,

Quote:

The hardest part is reducing cogging of the DD motor

The SP10 motor generates its own 3-phase sine drive signal, so there is no need to worry about waveforms, ramped or otherwise (if this is what you were referring to).
The motor and its original drive PCB act (electrically) just like an ordinary DC motor - increase the DC voltage and it runs faster / increases torque.
'Cogging' - well thats something that we iron out in the feedback compensator :-)

By 'noise' are you refering to 'noise' as an error/randomness in the speed setpoint?

Steerpike · 20th June 2008, 10:37 AM

I found this:
de.geocities.com/bc1a69/kaneta_eng.html
which has some interesting ideas.

rich121 · 21st June 2008, 06:47 PM

Are yoiu reffering to the different (MKI, MKII and MKIII) diagrams, or the plinth?
As for the plinth, I would personally use Russian Baltic Birch for the "constrained layer" effect, as this has been my wish all along, to seperate the motor into the plinth.
After isolating the motor like this, it would be much easier to have a slab of slate cut for I believe, even a better plinth... more mass, with the "constrained layer" still there.
"Butcher block" syle plinths, isolation platforms etc. have been found from other sites/forums posters to not be a good design..but, I guess there is always experimentation..

Rick

Steerpike · 21st June 2008, 11:37 PM

I was interested in both - since I have no plinth either.
But his use of variable transconductance op-amps to control the motor speed was interesting. I'd avoid that though because I'd want to use very ordinary and easy to source components.

rich121 · 23rd June 2008, 12:17 AM

Well, I hope that all goes well and that a controller/power supply can be designed to bring the SP-10 to it's full potential....
I am quite anxious to be honest..but, will be patient, as I would want the best design possible to be hashed out...

Keep us informed of any developments...

Rick

rich121 · 29th June 2008, 09:41 AM

I hope this project takes hold and is not just another wishful undertaking.... I'm very serious about this...

Rick

19th June 2008, 06:33 PM	#21
Shaun diyAudio Member Join Date: Aug 2001 Location: Cape Town, South Africa	If the source code is available, it would not be a major task to port it over to another chip. One can make allowances for obsolescence by making the controller board separate from the PSU and drivers, etc. So one just needs to make a new controller board with the same electrical interfaces. However, I've been pondering your idea of not reinventing the wheel (expressed in PM). One would have to replicate the main system blocks using currently available components, so the design effort required should be reduced. __________________ Shaun Onverwacht \|\|\|\|\|\|\|\|\|\| DON'T PANIC \|\|\|\|\|\|\|\|\|\|

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19th June 2008, 07:46 PM	#22
Steerpike diyAudio Member Join Date: Jan 2006 Location: Johannesburg, South Africa	How much of the original circuit have you 'reverse' engineered so far?

19th June 2008, 08:44 PM	#24
Zero Cool diyAudio Member Join Date: Sep 2004 Location: MN	The SP-10's has some very good noise floor. So whatever controller you build will have to be very sophisticated to be as quiet. ramped pulses, feedback loop for stability etc. The people that would have the most interest in something like this are archivist's that work with odd variety of disc's. The most important thing would be the pitch control. a very large +/- range would be helpful and it should be adjustable in semitones and cents not % which is about useless. Even if it read out in direct RPM would be better. Variable speed from 10tpm to 100rpm would be desirable. backwards play at any speed. the ability to control start up and stop speeds. etc. The controllers for these motors, for any of the technics direct drive motors are pretty well thought out. To duplicate one is no easy task! The hardest part is reducing cogging of the DD motor. the 10's had a -93dB noise floor if memory serves correct where as the 1200's and SP-25, SP-15's had something like -78db best of luck. let us know how it goes!

20th June 2008, 10:37 AM	#26
Steerpike diyAudio Member Join Date: Jan 2006 Location: Johannesburg, South Africa	I found this: de.geocities.com/bc1a69/kaneta_eng.html which has some interesting ideas.

21st June 2008, 06:47 PM	#27
rich121 diyAudio Member Join Date: Nov 2007	Are yoiu reffering to the different (MKI, MKII and MKIII) diagrams, or the plinth? As for the plinth, I would personally use Russian Baltic Birch for the "constrained layer" effect, as this has been my wish all along, to seperate the motor into the plinth. After isolating the motor like this, it would be much easier to have a slab of slate cut for I believe, even a better plinth... more mass, with the "constrained layer" still there. "Butcher block" syle plinths, isolation platforms etc. have been found from other sites/forums posters to not be a good design..but, I guess there is always experimentation.. Rick

21st June 2008, 11:37 PM	#28
Steerpike diyAudio Member Join Date: Jan 2006 Location: Johannesburg, South Africa	I was interested in both - since I have no plinth either. But his use of variable transconductance op-amps to control the motor speed was interesting. I'd avoid that though because I'd want to use very ordinary and easy to source components.

23rd June 2008, 12:17 AM	#29
rich121 diyAudio Member Join Date: Nov 2007	Well, I hope that all goes well and that a controller/power supply can be designed to bring the SP-10 to it's full potential.... I am quite anxious to be honest..but, will be patient, as I would want the best design possible to be hashed out... Keep us informed of any developments... Rick

29th June 2008, 09:41 AM	#30
rich121 diyAudio Member Join Date: Nov 2007	I hope this project takes hold and is not just another wishful undertaking.... I'm very serious about this... Rick

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