SP10 motor controller: Mark Kelly and Kaneta
Like Rich, I am sitting here waiting for more knowledgeable folks to get it done. Does anyone know how Mark Kelly's SP10 controller project is progressing? Also, has anyone seen or heard an SP10 being driven via the Kaneta controller? Is the latter just a schematic available on the net, a kit, or a finished product that one can purchase? Thanks for any info.
Like Rich, I am sitting here waiting for more knowledgeable folks to get it done. Does anyone know how Mark Kelly's SP10 controller project is progressing? Also, has anyone seen or heard an SP10 being driven via the Kaneta controller? Is the latter just a schematic available on the net, a kit, or a finished product that one can purchase? Thanks for any info.
Hi LewM,
Here is some information that I found, I think this is from the Kaneta project:
http://homepage2.nifty.com/~mhitaste/audiotop/audio_apparatus_page/sp-10mk2.html
Translated: http://translate.google.com/transla...-a&rls=org.mozilla:en-US:official&hs=bW5&sa=G
I hope someone can make some sense out of everything he has done!
Best regards,
Mark
Here is some information that I found, I think this is from the Kaneta project:
http://homepage2.nifty.com/~mhitaste/audiotop/audio_apparatus_page/sp-10mk2.html
Translated: http://translate.google.com/transla...-a&rls=org.mozilla:en-US:official&hs=bW5&sa=G
I hope someone can make some sense out of everything he has done!
Best regards,
Mark
I would like most of all to isolate the motor onto a plinth, with the controller/controls in a seperate enclosure, and a upgraded power supply.
I would like to be able to use 33/45/78 speeds still, and have a "trim" capability such as the MKIII has.
Also, possibly being able to "adjust" the controller to be able to use larger mass platters.
A digital readout on the controller showing speed would also be a nice plus, and this could also be used to show other information about the controller/motor.
Maybe now is a good time for everyone to add what they would also like, then maybe somehow we could narrow it down to what is actually possible?
Rick
I would like to be able to use 33/45/78 speeds still, and have a "trim" capability such as the MKIII has.
Also, possibly being able to "adjust" the controller to be able to use larger mass platters.
A digital readout on the controller showing speed would also be a nice plus, and this could also be used to show other information about the controller/motor.
Maybe now is a good time for everyone to add what they would also like, then maybe somehow we could narrow it down to what is actually possible?
Rick
Rich wrote, "Also, possibly being able to "adjust" the controller to be able to use larger mass platters."
This (the effect of platter mass on speed regulation) was the topic of a short discussion between Steerpike and Mark Kelly, I think. I am not sure how that really came out. One company I just discovered, Sound Hi-Fi in the UK, markets a copper platter mat for the SP10. The mat itself weighs 1.8kg. Thus it would alter the net platter mass by a fair percentage with respect to the baseline value. Yet there is no mention by the vendors that this mat could itself have an adverse effect, and I presume they have many satisfied customers. I would guess that the copper mat would not be a problem, in fact, but does anyone (still) here have an opinion based on a sound understanding of the mechanics? (I cannot recall who took which side in the Steerpike/Kelly discussion.) Thanks, anyone.
This (the effect of platter mass on speed regulation) was the topic of a short discussion between Steerpike and Mark Kelly, I think. I am not sure how that really came out. One company I just discovered, Sound Hi-Fi in the UK, markets a copper platter mat for the SP10. The mat itself weighs 1.8kg. Thus it would alter the net platter mass by a fair percentage with respect to the baseline value. Yet there is no mention by the vendors that this mat could itself have an adverse effect, and I presume they have many satisfied customers. I would guess that the copper mat would not be a problem, in fact, but does anyone (still) here have an opinion based on a sound understanding of the mechanics? (I cannot recall who took which side in the Steerpike/Kelly discussion.) Thanks, anyone.
Rich, I think it's just you and me at the moment. Unfortunately, we are a pretty worthless design team. I re-read the thread as regards platter mass, in relation to my possible purchase of that copper mat. I was incorrect in stating that Mark and Steerpike discussed the issue at length, but the preponderance of posts on that subject did suggest that platter mass has to be designed into the electronics and that a change in mass (e.g., if you add a 1.8kg copper mat instead of the stock rubber mat), could affect speed stabiity. (I recognize that the mass of the mat is distributed fairly evenly from spindle to outer circumference and therefore would not present as much of a problem as adding 1.8kg to the outer edge.) By extension, this means that one should use the stock rubber mat at all times in a unit with stock electronics. I am writing this in hopes that someone with a deeper understanding will tell me I'm correct or not correct.
Rich, I am fooling around with increasing the effective mass of the platter bearing assembly, a la the Albert Porter design.
Rich, I am fooling around with increasing the effective mass of the platter bearing assembly, a la the Albert Porter design.
I'm still here, and not given up! But as you will understand, these things all have to be fitted in when 'free' time is available.. alas never enough of it!
This is true. The servo system needs to be designed for a SPECIFIC inertial mass. However, its quite possible to include variable components in such a servo (variable resistors, or micro-controllers that can adjust their behaviour as needed). This would make it possible to have a user-selectable platter mass.
A heavier platter gives the system greater inherent resistance to disturbances, but when there *is* an error, it makes it harder (i.e., takes a longer time) for the motor & servo to correct it.
I think for home use, where fast run up time is not important, and the only disturbance is likely to be stylus drag, greater mass would be a good thing.
Changing the mass alone, with no correction in the electronics, will alter the system damping. I don't know the original design specs used by panasonic, but it most likely is based on close to critical damping - which is a good balance between oscillation, and slow response.
Altering the mass way beyond the system's capabilities can even make it unstable - where it will endlessly hunt either side of the desired speed and never lock.
This is true. The servo system needs to be designed for a SPECIFIC inertial mass. However, its quite possible to include variable components in such a servo (variable resistors, or micro-controllers that can adjust their behaviour as needed). This would make it possible to have a user-selectable platter mass.
A heavier platter gives the system greater inherent resistance to disturbances, but when there *is* an error, it makes it harder (i.e., takes a longer time) for the motor & servo to correct it.
I think for home use, where fast run up time is not important, and the only disturbance is likely to be stylus drag, greater mass would be a good thing.
Changing the mass alone, with no correction in the electronics, will alter the system damping. I don't know the original design specs used by panasonic, but it most likely is based on close to critical damping - which is a good balance between oscillation, and slow response.
Altering the mass way beyond the system's capabilities can even make it unstable - where it will endlessly hunt either side of the desired speed and never lock.
platter mass
Thank you very much for your cogent response. I guess therefore that you would agree that if one were to use an after-market platter mat on an SP10, it would be best to use one that is near to the same mass (weight, in this case) as that of the stock mat. I would guess that the stock rubber mat weighs about 300-400 gms. Therefore a 1.8-kg mat might throw things out of whack, even though the idea of a copper mat is very tempting. (Copper would have the added benefit of providing a shield from any EMI or RFI radiated from the electronics in the stock set-up, if you believe that's a problem at all.)
Thank you very much for your cogent response. I guess therefore that you would agree that if one were to use an after-market platter mat on an SP10, it would be best to use one that is near to the same mass (weight, in this case) as that of the stock mat. I would guess that the stock rubber mat weighs about 300-400 gms. Therefore a 1.8-kg mat might throw things out of whack, even though the idea of a copper mat is very tempting. (Copper would have the added benefit of providing a shield from any EMI or RFI radiated from the electronics in the stock set-up, if you believe that's a problem at all.)
A sheet of copper *foil* might be almost as good a screen, and not be significantly heavier.
I'm not sure that extra metal here would be much of an advantage over the platter itself. Copper IS a slightly better screen, I don't know how much noise is leaking through the platter as it is.
For magnetic screening, copper isn't so great, you need something called mu-metal (NiFe + other traces) for best results.
1.8kg is quite heavy - I think the original platter is something like 3.6kG isn't it (totally vague here, just a memory) ?
So you'd be altering it to 150% of it's normal value. Well, the best test is in the listening! If it sounds better, thats all that counts
I'm not sure that extra metal here would be much of an advantage over the platter itself. Copper IS a slightly better screen, I don't know how much noise is leaking through the platter as it is.
For magnetic screening, copper isn't so great, you need something called mu-metal (NiFe + other traces) for best results.
1.8kg is quite heavy - I think the original platter is something like 3.6kG isn't it (totally vague here, just a memory) ?
So you'd be altering it to 150% of it's normal value. Well, the best test is in the listening! If it sounds better, thats all that counts