Please correct me if I'm wrong, but I think this might be what Edmund Chan's MOBER DC Motor Kit offered, using a MAXON DC motor.
Not sure which MAXON DC motor model.
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Panos, I can only speak for my own deck, but I find stylus-drag to be almost a non-issue.
That is to say that the impact stylus-drag has on the platter speed is so minute, compared to the high degree of (errant) speed drift I otherwise observe, even when the stylus is NOT in the groove.
Yes, the stylus slows the platter very slightly, and reduces speed to a virtually identical degree on all music types. If I set the platter speed - by strobe - to be creeping ever-so-slightly fast, it typically works out to be bang-on 33RPM, once the stylus actually hits the groove.
[...At least until the speed drifts again!]
Niffy, based upon my research, I understand that the two power supply topologies have different strengths: -
SMPS: Superior voltage stability and accuracy; and
LPS: Lower noise. Greater dynamic peak capability
(I know the likes of iFi and others would NEVER agree, but anyway...)
I'm thinking of a hybrid approach.
Perhaps a quality Chinese SMPS AC-DC Bench Power Supply providing (say) 60V DC, followed by a DC-DC 24V Linear Power Supply - to feed the OL DC Motor Speed Controller.
Anyway, tomorrow my new AC-DC 20DC LPS should arrive, so I will run a few tests and report my findings.
In an early power supply experiment I tried using a voltage regulator, just a basic To220 7824. This should have given a stable low noise output. It would also limit instantaneous current to around 1.5A. As the motor is only going to draw milliamps I thought this would be ideal. It didn't work at all well. It just sucked the life out of the music. It seems to be that a higher current supply is what is needed. So for the OL a linear supply is probably going to be superior though a hybrid, as you suggest, may be better still.
My friend, who has the Linn Radikal, is thinking that he might upgrade it's smps with a linear. As he's not actually fitting it to a Sondek but adapting it for another for another deck it isn't going to be an easy drop in. He doesn't want to make any irreversible changes to it so that he can easily sell it on if it doesn't work out or if it is bested by the OL.
I tried the new LINEAR POWER SUPPLY (LPS) to drive the OL ADVANCED DC Motor Speed Control Unit (hereafter OL ADVANCED SCU) to drive our OL DC Motor.
I was disappointed to find that there was no change to the speed-drift issue using the new LPS. Also, the sound quality was much the same as when using our existing iFi iPower AC-DC 9V wall-wart to power the OL ADVANCED SCU.
I was further disappointed to find that the LPS only offered voltage variation from 8V to 10V - not right up to 20V as I understood from the specifications brief.
Of course, I tried increasing the power supply feed to 10V, but it made no sound quality difference that I could discern.
I've now packed-up the LPS - and back it goes!
So, I did NOT get the chance to play around with (materially) higher voltages feeding the OL ADVANCED SCU.
Based upon what NIFFY has shared above, I remain very keen to do that and will shoot for a higher voltage version - up to 24V.
Meanwhile, I have done a small amount of work on the OL ADVANCED SCU.
You can see the original PCB and components pictured above - and you will also see my attempts to add a bit of heatsinking with whatever I had lying around.
Later, I also replaced several of the smaller resistors on this PCB. There are only 9 resistors in total on this fairly simplistic circuit, but I did not have shelf-stock to replace all of them.
Essentially, I took several of the smaller resistors and up-rated their power handling from 1/4W to 2W resistors. It is my hope that this might introduce some additional thermal stability and thereby improve speed stability.
Let's see...
As an aside, I was quite surprised to find that none of the original removed resistors showed any signs of damage or deterioration.
Likewise, the original resistors that have remained in operation all look nice and clean and measure-up nicely.
In the event that speed-drift problem does NOT improve as a result of these recent minor changes, next I will up-size the capacitance of the 1000uF/63V to something like a 3900uF/63V or perhaps even bigger.
I will report.
I was disappointed to find that there was no change to the speed-drift issue using the new LPS. Also, the sound quality was much the same as when using our existing iFi iPower AC-DC 9V wall-wart to power the OL ADVANCED SCU.
I was further disappointed to find that the LPS only offered voltage variation from 8V to 10V - not right up to 20V as I understood from the specifications brief.
Of course, I tried increasing the power supply feed to 10V, but it made no sound quality difference that I could discern.
I've now packed-up the LPS - and back it goes!
So, I did NOT get the chance to play around with (materially) higher voltages feeding the OL ADVANCED SCU.
Based upon what NIFFY has shared above, I remain very keen to do that and will shoot for a higher voltage version - up to 24V.
Meanwhile, I have done a small amount of work on the OL ADVANCED SCU.
You can see the original PCB and components pictured above - and you will also see my attempts to add a bit of heatsinking with whatever I had lying around.
Later, I also replaced several of the smaller resistors on this PCB. There are only 9 resistors in total on this fairly simplistic circuit, but I did not have shelf-stock to replace all of them.
Essentially, I took several of the smaller resistors and up-rated their power handling from 1/4W to 2W resistors. It is my hope that this might introduce some additional thermal stability and thereby improve speed stability.
Let's see...
As an aside, I was quite surprised to find that none of the original removed resistors showed any signs of damage or deterioration.
Likewise, the original resistors that have remained in operation all look nice and clean and measure-up nicely.
In the event that speed-drift problem does NOT improve as a result of these recent minor changes, next I will up-size the capacitance of the 1000uF/63V to something like a 3900uF/63V or perhaps even bigger.
I will report.
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Niffy, did you ever compare the TRUE POINT controller to your best AC-DC 24V / OL SCU effort?
As you quite rightly point out, the TRUE POINT DC SCU boxes are very thoughtfully designed, with toroidal trannys on-board and quite a bit of regulation.
Certainly, with TRUE POINT you get a whole lot more in the box - but as we all know, this does not always guarantee better performance.
Any empirical feedback on the TRUE POINT stuff?
@niffy
Further my above question about your experience with TRUE POINT SCU, I wonder if running the PREMOTEC DC 12V Motor or a MAXON DC Motor is entirely fair.
I think we established (maybe) earlier in this thread that every DC motor has a somewhat unique loading requirement.
Charles at TRUE POINT recommends and promotes the PREMOTEC DC 24V Motor - as found in MICHELL GYRO DC Turntables - with the TRUE POINT SCU.
[Nobody has mentioned this DC 24V PREMOTEC Motor, so please comment if you have some experience with it…]
Is it possible that in your shootout with the TRUE POINT SCU, the playing field was skewed by the fact that (only) the OL SCU was tailored for the load of the DC motor used in the shootout?
This scenario could possibly render invalid many of the SCU shootouts that have been reported On this and other forums.
Does this make sense?
Further my above question about your experience with TRUE POINT SCU, I wonder if running the PREMOTEC DC 12V Motor or a MAXON DC Motor is entirely fair.
I think we established (maybe) earlier in this thread that every DC motor has a somewhat unique loading requirement.
Charles at TRUE POINT recommends and promotes the PREMOTEC DC 24V Motor - as found in MICHELL GYRO DC Turntables - with the TRUE POINT SCU.
[Nobody has mentioned this DC 24V PREMOTEC Motor, so please comment if you have some experience with it…]
Is it possible that in your shootout with the TRUE POINT SCU, the playing field was skewed by the fact that (only) the OL SCU was tailored for the load of the DC motor used in the shootout?
This scenario could possibly render invalid many of the SCU shootouts that have been reported On this and other forums.
Does this make sense?
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Hi SondekNZ,
When I compared the OL to the Truepoint I was using a Pink Triangle Anniversary turntable. The PT uses a Premotec 29mm with a tacho. I don't know for certain which motor though I suspect it is the 9v. This motor was not ideally suited to the OL as it ran a little bit fast even at the lowest setting. Comparisons had to be done using 45rpm records. TP is a Pink Triangle specialist and their controller is designed specifically for the Anniversary. The test conditions were therefore not ideal with a probable advantage going to the TP.
The OL controller with my PSU still bested the TP controller by quite a margin. I have not directly compared the TP to the Ultra controller, only the Advanced. I have only compared the Advanced to the Ultra using the Maxon.
The OL controllers seem to be quite happy with a wide range of loading. The Motor supplied by OL, Premotec 18105, has a terminal resistance of 12.5Ω. The Maxon 226764 is much higher at 104Ω. The motor on the Anniversary is only ~6Ω. The OL controllers seem perfectly happy with a very wide range of loads.
Niffy
When I compared the OL to the Truepoint I was using a Pink Triangle Anniversary turntable. The PT uses a Premotec 29mm with a tacho. I don't know for certain which motor though I suspect it is the 9v. This motor was not ideally suited to the OL as it ran a little bit fast even at the lowest setting. Comparisons had to be done using 45rpm records. TP is a Pink Triangle specialist and their controller is designed specifically for the Anniversary. The test conditions were therefore not ideal with a probable advantage going to the TP.
The OL controller with my PSU still bested the TP controller by quite a margin. I have not directly compared the TP to the Ultra controller, only the Advanced. I have only compared the Advanced to the Ultra using the Maxon.
The OL controllers seem to be quite happy with a wide range of loading. The Motor supplied by OL, Premotec 18105, has a terminal resistance of 12.5Ω. The Maxon 226764 is much higher at 104Ω. The motor on the Anniversary is only ~6Ω. The OL controllers seem perfectly happy with a very wide range of loads.
Niffy
Out of curiosity, I just measured across the terminals of our (disconnected) OL DC-100 from 2004 - presumably some form of PREMOTEC variant - and it measured 30.5-Ohms.
Using the OL metal pulley supplied by OL with this near 20-year old motor, it requires 3.85V to drive our LP12 platter at 33.33RPM.
Does this data sound familiar enough to anyone, to hazard a guess at a PREMOTEC model number for this (old) DC motor?
Using the OL metal pulley supplied by OL with this near 20-year old motor, it requires 3.85V to drive our LP12 platter at 33.33RPM.
Does this data sound familiar enough to anyone, to hazard a guess at a PREMOTEC model number for this (old) DC motor?
Sondeknz, I have also recently measured the resistance of my Premotec 18105. I've taken multiple measurements at various angles of the rotor. The mean value of those measurements was 27.5 Ohms, for all intents and purposes quite close to your measurement. By the way, have you taken one or more measurements of the resistance?
As mentioned, I am running the Premotec 18105 with an OL Advanced Controller to drive my Roksan Xerxes. The Roksan is driven at the subplatter, which measures 16.35cm in diameter. So, in order to achieve 33.333rpm, my motor runs at 727rpm. At that speed, the motor runs at 2.52V
I do not know whether that helps, but one can have at least a reference for an implementation with the Roksan Xerxes (original, not later models).
Cheers,
Panos
P.S. By the 25th of April I expect to have received my new Maxon RE-max 226764 motor and I will test it in place of the Premotec. I will report back with my findings.
As mentioned, I am running the Premotec 18105 with an OL Advanced Controller to drive my Roksan Xerxes. The Roksan is driven at the subplatter, which measures 16.35cm in diameter. So, in order to achieve 33.333rpm, my motor runs at 727rpm. At that speed, the motor runs at 2.52V
I do not know whether that helps, but one can have at least a reference for an implementation with the Roksan Xerxes (original, not later models).
Cheers,
Panos
P.S. By the 25th of April I expect to have received my new Maxon RE-max 226764 motor and I will test it in place of the Premotec. I will report back with my findings.
Many thanks Panos,
I've only taken one measurement of our OL DC-100 motor, while it was unplugged and resting - and the 30.5-Ohms includes the length of cable from the OL ADVANCED DC SCU to the motor.
(It is just so easy to measure from the ill-fitting OL male connector that plugs into the SCU...)
Our ORIGIN LIVE pulley diameter is approx. 7.3mm at the "crown" meaning that DC-100 gains reasonably high RPM that I think it prefers. The LINN sub-chassis drive diameter is about 162mm. I know there is a math calc to work all this out, but I am not on top of this aspect.
I'll try to take some more readings of the motor when it is connected, as this is bound to skew the measurements - but I need to figure-out exactly how. In any event, I'll NOT be surprised if it reads very close to 27.5-Ohms.
Anyways, it seems like we might currently be running the same sweet little old PREMOTEC DC motor.
All that is about to change with your new MAXON motor.
Can't wait to read all about it!
I've only taken one measurement of our OL DC-100 motor, while it was unplugged and resting - and the 30.5-Ohms includes the length of cable from the OL ADVANCED DC SCU to the motor.
(It is just so easy to measure from the ill-fitting OL male connector that plugs into the SCU...)
Our ORIGIN LIVE pulley diameter is approx. 7.3mm at the "crown" meaning that DC-100 gains reasonably high RPM that I think it prefers. The LINN sub-chassis drive diameter is about 162mm. I know there is a math calc to work all this out, but I am not on top of this aspect.
I'll try to take some more readings of the motor when it is connected, as this is bound to skew the measurements - but I need to figure-out exactly how. In any event, I'll NOT be surprised if it reads very close to 27.5-Ohms.
Anyways, it seems like we might currently be running the same sweet little old PREMOTEC DC motor.
All that is about to change with your new MAXON motor.
Can't wait to read all about it!
Thanks Niffy.
If my DC-100 is in fact an 18V (Max) DC motor, running at 3.85V for 33RPM may explain why it has lasted 20-years and still (barely) purrs like a kitten.
If my DC-100 is in fact an 18V (Max) DC motor, running at 3.85V for 33RPM may explain why it has lasted 20-years and still (barely) purrs like a kitten.
My motor is definitely the 18105 (proof provided in the attachment), as I bought it from OL before they launched then DC100, DC200 designation (at some point they also had a DC300).
My new challenge is to find a pulley for the RE-max motor I am expecting. It has a 3mm shaft (axle). I would like to try pulleys of various diameters, say 10mm, 20mm or even 30mm. And I wonder whether I should go for metallic or plastic pulley.
Anybody can give a hint about where I should look? Thanks in advance.
My new challenge is to find a pulley for the RE-max motor I am expecting. It has a 3mm shaft (axle). I would like to try pulleys of various diameters, say 10mm, 20mm or even 30mm. And I wonder whether I should go for metallic or plastic pulley.
Anybody can give a hint about where I should look? Thanks in advance.
Attachments
Here in China, there are pulleys made of everything, every shape and every size.
Nothing is a problem - as long as you want 100 of them! 🤣
I would try to get a "crown" shaped barrel made of PTFE. That stuff is incredibly hard, hard wearing and has some nice dampening qualities that I like.
Personally, I'm a fan of having a pulley with a big old flywheel on it somewhere to (theoretically) further smooth any motor noise... if you can squeeze it in.
Give ALI EXPRESS a look...
Nothing is a problem - as long as you want 100 of them! 🤣
I would try to get a "crown" shaped barrel made of PTFE. That stuff is incredibly hard, hard wearing and has some nice dampening qualities that I like.
Personally, I'm a fan of having a pulley with a big old flywheel on it somewhere to (theoretically) further smooth any motor noise... if you can squeeze it in.
Give ALI EXPRESS a look...
PTFE is quite a soft plastic famed for it's low friction. Belt slip would be more likely with this material than with any other. It is also not brilliant for dimensional stability.
I believe that a better option is Delrin, also known as Acetal or POM. The homopolymer variety of acetal would probably be marginally better than the copolymer version. Delrin is of the homopolymer variety.
Delrin is exceptionally easy to machine and has excellent dimensional stability. Although it is also a low friction material it's coefficient of friction is typically over twice as high as PTFE. It also has good damping properties.
My current pulley is made of Delrin.
Niffy
I believe that a better option is Delrin, also known as Acetal or POM. The homopolymer variety of acetal would probably be marginally better than the copolymer version. Delrin is of the homopolymer variety.
Delrin is exceptionally easy to machine and has excellent dimensional stability. Although it is also a low friction material it's coefficient of friction is typically over twice as high as PTFE. It also has good damping properties.
My current pulley is made of Delrin.
Niffy
For the moment, for my rim-drive use case, I have ordered a few tape deck capstans, to use them as pulleys on the Maxon motor I am expecting. They are rubber coated of course.
Alternatively, I intend to also try a belt-drive with a tensioner idler-wheel, to secure maximum contact circumference (arc) between pulley and belt (see photo from Artemis belt-drive). I will try two different belt materials, namely polyester thread and PET tape.
Many interesting things to try. In the meantime, I am measuring the wow & flutter of my rim-drive Xerxes (rim-drive) and it's around 0.15%. I do not know whether I will be able to improve that with my new Maxon motor and capstan-based pulley...
Panos
Alternatively, I intend to also try a belt-drive with a tensioner idler-wheel, to secure maximum contact circumference (arc) between pulley and belt (see photo from Artemis belt-drive). I will try two different belt materials, namely polyester thread and PET tape.
Many interesting things to try. In the meantime, I am measuring the wow & flutter of my rim-drive Xerxes (rim-drive) and it's around 0.15%. I do not know whether I will be able to improve that with my new Maxon motor and capstan-based pulley...
Panos
