Stefano,
Making a box and pulleys should not be a problem. If the DC motor directly drives the platter then there is no need to engineer the motor bearings, but the motor would need good bearings. If we mount the motor to the box with sorbothane gasket, or the box has rubber or sorbothane feet and the O-ring is properly sized with right hardness of material, we should be able to isolate any motor bearing noise away from the platter. And the platter should have mass to avoid being easily excited.
Do you think the other guys will like the Rim drive idea? I am interested in trying a solution to remove belts.
What is the solution for the platter and bearing? I can make a platter and I can make a bearing, but I do not think my bearing is going to impress anyone since I do not have that experience.
Jamie
Making a box and pulleys should not be a problem. If the DC motor directly drives the platter then there is no need to engineer the motor bearings, but the motor would need good bearings. If we mount the motor to the box with sorbothane gasket, or the box has rubber or sorbothane feet and the O-ring is properly sized with right hardness of material, we should be able to isolate any motor bearing noise away from the platter. And the platter should have mass to avoid being easily excited.
Do you think the other guys will like the Rim drive idea? I am interested in trying a solution to remove belts.
What is the solution for the platter and bearing? I can make a platter and I can make a bearing, but I do not think my bearing is going to impress anyone since I do not have that experience.
Jamie
Stefano, aren't these multiple motor solutions with flywheel just trying to "fix" bad motor designs and controls. I thought the idea was to go to a better motor with excellent control to allow for direct drive of the platter?
If the motors are noisy, and there are three motors, 3X the noise, the only way the flywheel can avoid noise is to have bearings that are vibration dampening. It think this is just moving the problem around to different places instead of solving the problem directly.
The drive pulley will need a dampening contact point with the platter, like an O-ring, or the entire pulley is rubber like Thorens, then it can be directly mounted to the motor. If the motor is noisy, then don't we have the wrong motor? Then we are back where we started?
Jamie
If the motors are noisy, and there are three motors, 3X the noise, the only way the flywheel can avoid noise is to have bearings that are vibration dampening. It think this is just moving the problem around to different places instead of solving the problem directly.
The drive pulley will need a dampening contact point with the platter, like an O-ring, or the entire pulley is rubber like Thorens, then it can be directly mounted to the motor. If the motor is noisy, then don't we have the wrong motor? Then we are back where we started?
Jamie
No, because differently from VPI, we would drive the flywheel directly.
The flywheel and the 3 motors allow IMHO the following things:
1) more torque, so better regulation under stylus drag without the need of too much feedback but only the tachometer to allow for long run drifts
2) more uniform rotation for better pitch
3) Flywheel will further reduce the low noise that can be transmitted to the stylus resulting in a stunning low noise design if combined with very high quality DC motors that have lots of torque and low noise
4) The flywheel has to be a little heavy and this improves further the rotation stability through the extra flywheel effect.
5) a bigger with wider diameter flywheel will allow for speed reduction thus letting us run the DC motor at a higher speed than 300-400RPM thus obtaining more juice (torque) out of the magnet.
These are my main reason for doing this. I think I should apply for the intellectual propriety on this as I don't think that there is something like this in the market currently.
Something similar but not this 🙂
Anyway, I think that if we can implement the mechanical aspect, a top level electronics to control the motor can be done and a precise firmware to control the rotation will certainly be done by Pyramid!...he is the master!!!
😎
Also, I want to add, that our goal should be not to underestimate anything.
For example, give for granted that the DC motor has such a low vibration noise that it doesn't matter or not worth it to find ways to lower it even more.
For instance we should work out the best way to install the motors even if the motor is extremely good.
This is DIY we don't have restriction if we spend few dollars more.
My goal here is to get the best motor drive we can have, see if we can make it 😀
I am on this now and so is Pyramid, if Jamie, you can take care of the mechanical aspect i.e. produce parts and also figure out the best mechanical way to install the elements we are all set.
Obviously I hope that knowledgeable people here along the way feel to cheap in and give us some suggestion as well.
This is a very exciting project. I wasn't planning on doing this, but now that I think about it..... 😱
Let's get it done 😎
For example, give for granted that the DC motor has such a low vibration noise that it doesn't matter or not worth it to find ways to lower it even more.
For instance we should work out the best way to install the motors even if the motor is extremely good.
This is DIY we don't have restriction if we spend few dollars more.
My goal here is to get the best motor drive we can have, see if we can make it 😀
I am on this now and so is Pyramid, if Jamie, you can take care of the mechanical aspect i.e. produce parts and also figure out the best mechanical way to install the elements we are all set.
Obviously I hope that knowledgeable people here along the way feel to cheap in and give us some suggestion as well.
This is a very exciting project. I wasn't planning on doing this, but now that I think about it..... 😱
Let's get it done 😎
Stefan's, Am I right that the VPI has compliant suspension posts and the motor is fixed solid to the furniture base or are both in equallibrium regarding their foundation?
I can't imagine a loose combination with a tight rim drive?
Regards
David
I can't imagine a loose combination with a tight rim drive?
Regards
David
No motors are fixed to the box for sure. The AC motor cannot be left floating or they will make a heck of a noise especially driven by their SDS.
Now, if you had a 24V motor and Pyramid supply, then the motor's vibration will go really low!!!
Our arrangement will be all fixed to the separate box, no floating suspensions going on.
The only thing is that the flywheel will need a very good bearing at least as good as the TT that goes to power up 🙂
Now, if you had a 24V motor and Pyramid supply, then the motor's vibration will go really low!!!
Our arrangement will be all fixed to the separate box, no floating suspensions going on.
The only thing is that the flywheel will need a very good bearing at least as good as the TT that goes to power up 🙂
Little update.
Since the lack of apparent interest for this more complicated and ambitious project with 3 motors, and after having talked with Pyramid, we decide to put this bigger project on hold for the following reasons:
1) the level of complication, therefore the amount of time that we would have to invest on this, would go behind the simple DIY project and we all have our daily challenges, probably unwise to add more 🙂
2) the cost of the final product will be very high just considering the use of 3 expensive motors, plus controller plus all other parts, therefore will preclude a lot of people from pursue it.
3) controller alone would be way too complicated for people to assemble (all SMD parts and also very hard to solder) and debug for any problem.
4) we are not sure that the benefit of having 3 motors, vs the problem to keep them synchronized would overcome the advantage of such a system (in my opinion it might but it is too much work to prove at this point).
For the following reasons, if there are more people on board, and only if there are people that like the idea and will support it, we will move forward and develop the initial idea of one motor with tachometer and minimum feedback.
The external pod has to has to be suitable for the majority of the TT out there so that many people will benefit from it.
We await your response to see if there is any interest on this and sorry for the confusion but hopefully, the explanation above, makes some sense to you all!
Since the lack of apparent interest for this more complicated and ambitious project with 3 motors, and after having talked with Pyramid, we decide to put this bigger project on hold for the following reasons:
1) the level of complication, therefore the amount of time that we would have to invest on this, would go behind the simple DIY project and we all have our daily challenges, probably unwise to add more 🙂
2) the cost of the final product will be very high just considering the use of 3 expensive motors, plus controller plus all other parts, therefore will preclude a lot of people from pursue it.
3) controller alone would be way too complicated for people to assemble (all SMD parts and also very hard to solder) and debug for any problem.
4) we are not sure that the benefit of having 3 motors, vs the problem to keep them synchronized would overcome the advantage of such a system (in my opinion it might but it is too much work to prove at this point).
For the following reasons, if there are more people on board, and only if there are people that like the idea and will support it, we will move forward and develop the initial idea of one motor with tachometer and minimum feedback.
The external pod has to has to be suitable for the majority of the TT out there so that many people will benefit from it.
We await your response to see if there is any interest on this and sorry for the confusion but hopefully, the explanation above, makes some sense to you all!
Stefanoo:
The word "expensive" is a relative term. Lets see what you come up with. The use of 3 motors is a definite step up from a single motor as I mentioned in a previous post, but start with one motor and see how it works out.
Everybody has their own priorities and budget. Just for your information, the latest 3 motor assembly and motor controller from TW Acoustic can also run off a built in battery supply that will spin a turntable for several hours or run off wall power. As you might guess it is very expensive but so is Mercedes, Rolex, and some bottles of wine. Choices, choices, choices.
The word "expensive" is a relative term. Lets see what you come up with. The use of 3 motors is a definite step up from a single motor as I mentioned in a previous post, but start with one motor and see how it works out.
Everybody has their own priorities and budget. Just for your information, the latest 3 motor assembly and motor controller from TW Acoustic can also run off a built in battery supply that will spin a turntable for several hours or run off wall power. As you might guess it is very expensive but so is Mercedes, Rolex, and some bottles of wine. Choices, choices, choices.
yes it is a relative terms. BTW I own a Mercedes I know what you mean 😉
The problem for the expense is that the majority of people I see here around the forum mostly engage on projects that are relatively cheap or that are cheaper version of commercial projects.
Also the controller should come pre-assembled and tested as it would be really tough for the great majority here to assemble and test.
Now, a 3 motor kind of deal, will require a lot of R&D and time money for who develops it, and becomes more of a professional project that anybody would do for commercial purpose.
So I will turn that down for now and IF there is interest in this thing, Pyramid and I can continue on the one motor solution.
We need somebody who will be capable of developing pulley and metal pod and assembly for the motor.
IF Jamie is still on board to help us with the mechanical aspect, then we can continue.
Please let's confirm if there are people who want to see this project get done 😀
P.S. TW makes really interesting projects, but they do it for a living they have more than one person working full time on their projects, which makes a huge difference...especially considering that the people who work on these things make a revenue as well which is another plus...if you know what I mean!
😎
The problem for the expense is that the majority of people I see here around the forum mostly engage on projects that are relatively cheap or that are cheaper version of commercial projects.
Also the controller should come pre-assembled and tested as it would be really tough for the great majority here to assemble and test.
Now, a 3 motor kind of deal, will require a lot of R&D and time money for who develops it, and becomes more of a professional project that anybody would do for commercial purpose.
So I will turn that down for now and IF there is interest in this thing, Pyramid and I can continue on the one motor solution.
We need somebody who will be capable of developing pulley and metal pod and assembly for the motor.
IF Jamie is still on board to help us with the mechanical aspect, then we can continue.
Please let's confirm if there are people who want to see this project get done 😀
P.S. TW makes really interesting projects, but they do it for a living they have more than one person working full time on their projects, which makes a huge difference...especially considering that the people who work on these things make a revenue as well which is another plus...if you know what I mean!
😎
My thinking, right or wrong is that it seems that simple isn't sufficient, but complicated is. Synchronous motor vs complicated drive.
I'll be watching too.
I'll be watching too.
Stefanoo:
The motor pod would be fairly easy. You can use something like a 4" Or 5" heavy wall aluminum tube and use 1/2" thick or so aluminum cap for the bottom and some thick delrin for a top cap where the motor will be secured. Just one of many options.
The motor pod would be fairly easy. You can use something like a 4" Or 5" heavy wall aluminum tube and use 1/2" thick or so aluminum cap for the bottom and some thick delrin for a top cap where the motor will be secured. Just one of many options.
I have a synchronous motor and they are fairly noisy if compared to DC motors, not sure what you are trying to say.
3 motors idea was fairly complicated for the purpose of this and the result is uncertain and requires a lot of work.
All I mean is that you have spent so much time questioning/remarking the synchronous motors are noisy. They may have noise, but have you tried to isolate one in your "outboard" container/mount to see how much diffference it makes? I've spent a number of hours on ebay looking a broadcast quality turntables from the pre direct drive era & they're all 1800 rpm synchronous motors. Somehow for that use they weren't too noisy. So much discussion on how to build a motor controller for a DC motor... Let me ask you...what does your location mean? Italy or Wisconsin USA? Cost to ship to Wisconsin is a lot less than to Italy.
1 1800 rpm motor, maybe an idler in between & then a driving wheel (actually another idler) to the rim of the turntable might be simpler, but I don't know either.
1 1800 rpm motor, maybe an idler in between & then a driving wheel (actually another idler) to the rim of the turntable might be simpler, but I don't know either.
the only good use that 3 motors will serve is stability/centralisation of the main platter bearing. the reduced noise of the main bearing will be nulled by the noise of 3 rim drive motors. so what you gain one way you loose the other. it's not always about horsepower.
anyone can build a turntable but will it sound good is another question. there is a loooot more that goes into turntable design than people think.
here is another teaser to get your head round. why rim drive when you could go underneath and drive from the underside of the platter. this in theory would put less force on the platter bearing and keep it more central. now go and have a good think about it and come back with an answer why its not a good idea.
anyone can build a turntable but will it sound good is another question. there is a loooot more that goes into turntable design than people think.
here is another teaser to get your head round. why rim drive when you could go underneath and drive from the underside of the platter. this in theory would put less force on the platter bearing and keep it more central. now go and have a good think about it and come back with an answer why its not a good idea.
gvasale;
The sad truth is that to my knowledge, there are no synchronous motors made today that are any where near the quality of a good dc motor. Synchronous motors are noisy, under powered and cheaply made. You can make a synchronous motor work, but will never perform as well as a good dc motor with a proper controller and there is no way around it. Once you hear the difference there is no going back.
The sad truth is that to my knowledge, there are no synchronous motors made today that are any where near the quality of a good dc motor. Synchronous motors are noisy, under powered and cheaply made. You can make a synchronous motor work, but will never perform as well as a good dc motor with a proper controller and there is no way around it. Once you hear the difference there is no going back.
Don't see how a tachometer would help - it measures only the shaft speed, not the platter speed.
And anyhow, why don't you guys read the original Teres design history instead of reinventing everything afresh?
As i seem to vaguely recall, Manfred Huber donated his controller design to the Teres team. It is centered around a Maxon DC motor with no tacho coils.
Instead, correct speed is set from a strobe printout on the bottom of the platter which a photodiode counts. The controller code is pretty simple and anyone with a bit of experience in control can put it together. Initial voltage is set higher to get quickly up to speed and subsequent adjustments are done infrequently through a slow integrator.
I use the same motor but have never felt a burning need for dead-on correct speed. Getting clean dc in a way that sounds good to my ears has been a priority.
I think the concept we are proposing is to use a DC or Brushless DC motor with the most advanced speed, power, waveform and noise control available. Pyramid's PSU's use the most advanced programmable and digital processing bits available. This is technology that was not available in legacy designs.
The correctly designed PSU would allow for multiple motors within the same basic motor design, speed, and power range. We can then use the power of crowd testing for the best motor. Imagine a single advanced PSU tested against dozens or 100's of motors to find the quietest motor with the best bearings, torque, speed stability, price etc.
All previous implementations of DC motors required exact matching of PSU to motor. You really couldn't change one without the other.
IMHO the design should be One motor, One PSU, One Platter and potentially allow for multiple drive options, Rim, belt, etc.
I would speculate that a Rim drive would work best with a heavier platter and better bearing, and folks with lighter platters might benefit from a softer touch of a belt.
I think the focus should be on solving the DIY build issues for making the best platter bearing, platter, and plinth. Finding the best drive motor, the best drive pulley, etc.
All of these different ideas for multiple motors, idler wheels, flywheels, etc. are all trying to solve badly engineered mechanical systems and every additional moving part is another potential source of noise that needs another solution and round and round it goes.
With a single simple drive system design. One motor, one drive pulley, one platter, the collective resources of the community can find the very best material for the drive pulley (rubber, urethane, silicone, whatever), the best motor, the best motor mount (again many materials of many hardness, compliance, etc. can be tested if the design is flexible). Even Sorbothane comes in multiple durometers and the mounting can be pre-loaded for a firm, yet dampening mounting of motor, etc.
A simple design is not engineered simply. It takes much more effort to make a correct simple system, but the best designs are most definitely simple.
The correctly designed PSU would allow for multiple motors within the same basic motor design, speed, and power range. We can then use the power of crowd testing for the best motor. Imagine a single advanced PSU tested against dozens or 100's of motors to find the quietest motor with the best bearings, torque, speed stability, price etc.
All previous implementations of DC motors required exact matching of PSU to motor. You really couldn't change one without the other.
IMHO the design should be One motor, One PSU, One Platter and potentially allow for multiple drive options, Rim, belt, etc.
I would speculate that a Rim drive would work best with a heavier platter and better bearing, and folks with lighter platters might benefit from a softer touch of a belt.
I think the focus should be on solving the DIY build issues for making the best platter bearing, platter, and plinth. Finding the best drive motor, the best drive pulley, etc.
All of these different ideas for multiple motors, idler wheels, flywheels, etc. are all trying to solve badly engineered mechanical systems and every additional moving part is another potential source of noise that needs another solution and round and round it goes.
With a single simple drive system design. One motor, one drive pulley, one platter, the collective resources of the community can find the very best material for the drive pulley (rubber, urethane, silicone, whatever), the best motor, the best motor mount (again many materials of many hardness, compliance, etc. can be tested if the design is flexible). Even Sorbothane comes in multiple durometers and the mounting can be pre-loaded for a firm, yet dampening mounting of motor, etc.
A simple design is not engineered simply. It takes much more effort to make a correct simple system, but the best designs are most definitely simple.
analog_sa,
Pyramid already has a tach that reads from the platter using a very accurate sensor. It is an easy DIY modification and extremely accurate. I would expect we would want to measure speed at the platter as that is what matters. I think the correct PSU will adjust for minor variations in platter diameter, pulley diameter, temperature, etc. The Pyramid PSU is a complete solution within the limits of the motor type used.
Jamie
Pyramid already has a tach that reads from the platter using a very accurate sensor. It is an easy DIY modification and extremely accurate. I would expect we would want to measure speed at the platter as that is what matters. I think the correct PSU will adjust for minor variations in platter diameter, pulley diameter, temperature, etc. The Pyramid PSU is a complete solution within the limits of the motor type used.
Jamie
Bibio,
A 90 degree sub platter drive would require a matching platter design and putting the drive motor closer to the platter bearing making it much more difficult to retrofit the drive to any other platter. Also the 90 degree drive includes some amount of shear force on the drive pulley since the contact patch is linear. All undesirable conditions for drive.
Even if, that's a big if, the subplatter drive solved platter bearing issues, it creates other issues more difficult to solve broadly in a way that can be built by others.
If the platter and bearing have a problem with a rim drive, there is a problem that should be solved directly. Better bearing, heavier platter, better drive pulley, better motor or whatever. Again, all in a very simple mechanical layout that allows DIYers to make their own bearings, platters or plinths to test for best performance and then share results. This is the opposite of the commercial designs with gimmicky designs, lot's of little parts that are cheap to make on machines and very light for cheap shipping. Why do you think we have constrained layer dampening? Because heavy plinths and platters are expensive to make and ship. Mass is good for audio, but bad for profit.
If we make a decision for a particular mechanical configuration then we can focus on the details of implementation. If we continually change the overall mechanism we never know if the improvement is from a better execution or by rearranging the bits, and round and round we go.
My proposal is to keep the mechanical design brutally simple and then use the power of the crowd to find the best execution which includes materials selection, dampening schemes, etc. and allow for individual modification. All sharing the same PSU.
We can source some enclosures for the motor for pods, but also allow for someone to mount the motor in their own plinth, etc.
Jamie
A 90 degree sub platter drive would require a matching platter design and putting the drive motor closer to the platter bearing making it much more difficult to retrofit the drive to any other platter. Also the 90 degree drive includes some amount of shear force on the drive pulley since the contact patch is linear. All undesirable conditions for drive.
Even if, that's a big if, the subplatter drive solved platter bearing issues, it creates other issues more difficult to solve broadly in a way that can be built by others.
If the platter and bearing have a problem with a rim drive, there is a problem that should be solved directly. Better bearing, heavier platter, better drive pulley, better motor or whatever. Again, all in a very simple mechanical layout that allows DIYers to make their own bearings, platters or plinths to test for best performance and then share results. This is the opposite of the commercial designs with gimmicky designs, lot's of little parts that are cheap to make on machines and very light for cheap shipping. Why do you think we have constrained layer dampening? Because heavy plinths and platters are expensive to make and ship. Mass is good for audio, but bad for profit.
If we make a decision for a particular mechanical configuration then we can focus on the details of implementation. If we continually change the overall mechanism we never know if the improvement is from a better execution or by rearranging the bits, and round and round we go.
My proposal is to keep the mechanical design brutally simple and then use the power of the crowd to find the best execution which includes materials selection, dampening schemes, etc. and allow for individual modification. All sharing the same PSU.
We can source some enclosures for the motor for pods, but also allow for someone to mount the motor in their own plinth, etc.
Jamie
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