David, that makes perfect sense, a great analogy.
Stefano, the biggest consideration for me in an idler would be putting any pulley size induced noise irregularities below the most sensitive audio region. The last thing you want is a pulley/platter ratio that puts the nominal pulley rotation speed smack bang in the middle of the most sensitive frequency range of our hearing. Try to get that motor rotating under 1k rpm if possible.
Stefano, the biggest consideration for me in an idler would be putting any pulley size induced noise irregularities below the most sensitive audio region. The last thing you want is a pulley/platter ratio that puts the nominal pulley rotation speed smack bang in the middle of the most sensitive frequency range of our hearing. Try to get that motor rotating under 1k rpm if possible.
Don't worry about the choice of the motor, pyramid and I take care of selection and every electrical/control s aspect.
The motor I selected will work perfectly you will see
Yes that's the idea, we are trying to get it between 600-900RPM.
Is there any rule of thumb we should be aware of?
The best we can do is to get the parts machined as tight as possible.
We were talking about even balancing the idler.
I don't think that other manufacturer ls don't do anything more specials...do they?
I don't think the idler will require balancing since it's relatively small in Dia. Machining would be out of billet anyway and rotational speed pressed up against the rim is slow.
The platter always needs balancing and is the main contributor
Of more concern is, since you will have side loads on all 3 axis tightly coupled, the motor has the highest speed with highest vibration with the smallest DIA. Shaft.
That's a potential wear issue that maybe the motor mfg. never intended to be used this way, with a tight rubber interface side loaded. You might check if they have side load specs?
Motors are expensive and a quick check is free info.
Regards
David
The platter always needs balancing and is the main contributor
Of more concern is, since you will have side loads on all 3 axis tightly coupled, the motor has the highest speed with highest vibration with the smallest DIA. Shaft.
That's a potential wear issue that maybe the motor mfg. never intended to be used this way, with a tight rubber interface side loaded. You might check if they have side load specs?
Motors are expensive and a quick check is free info.
Regards
David
David,
FYI the specs on the dcx22:
General data
Status provisional
Values at nominal voltage
Nominal voltage 48 V
No load speed 5220 rpm
No load current 5.16 mA
Nominal speed 4180 rpm
Nominal torque (max. continuous torque) 27.9 mNm
Nominal current (max. continuous current) 0.323 A
Stall torque 140 mNm
Starting current 1.6 A
Max. efficiency 89 %
Characteristics
Terminal resistance 29.9 Ω
Terminal inductance 2.8 mH
Torque constant 87.6 mNm/A
Speed constant 109 rpm/V
Speed / torque gradient 37.3 rpm/mNm
Mechanical time constant 3.17 ms
Rotor inertia 8.12 gcm²
Thermal data
Thermal resistance housing-ambient 13.6 K/W
Thermal resistance winding-housing 4.57 K/W
Thermal time constant winding 19.2 s
Thermal time constant motor 607 s
Ambient temperature -30...+85 °C
Max. permissible winding temperature +100 °C
Mechanical data
Bearing Type sleeve bearing
Max. permissible speed 7160 rpm
Axial play 0 - 0.18 mm
Radial play 0.02 mm
Max. axial load (dynamic) 0.1 N
Max. force for press fits (static) 80 N
(static, shaft supported) 440 N
Max. radial loading 3 N, 5 mm from flange
Other specifications
Number of pole pairs 1
Number of commutator segments 9
Direction of rotation Clockwise (CW)
Number of autoclave cycles
FYI the specs on the dcx22:
General data
Status provisional
Values at nominal voltage
Nominal voltage 48 V
No load speed 5220 rpm
No load current 5.16 mA
Nominal speed 4180 rpm
Nominal torque (max. continuous torque) 27.9 mNm
Nominal current (max. continuous current) 0.323 A
Stall torque 140 mNm
Starting current 1.6 A
Max. efficiency 89 %
Characteristics
Terminal resistance 29.9 Ω
Terminal inductance 2.8 mH
Torque constant 87.6 mNm/A
Speed constant 109 rpm/V
Speed / torque gradient 37.3 rpm/mNm
Mechanical time constant 3.17 ms
Rotor inertia 8.12 gcm²
Thermal data
Thermal resistance housing-ambient 13.6 K/W
Thermal resistance winding-housing 4.57 K/W
Thermal time constant winding 19.2 s
Thermal time constant motor 607 s
Ambient temperature -30...+85 °C
Max. permissible winding temperature +100 °C
Mechanical data
Bearing Type sleeve bearing
Max. permissible speed 7160 rpm
Axial play 0 - 0.18 mm
Radial play 0.02 mm
Max. axial load (dynamic) 0.1 N
Max. force for press fits (static) 80 N
(static, shaft supported) 440 N
Max. radial loading 3 N, 5 mm from flange
Other specifications
Number of pole pairs 1
Number of commutator segments 9
Direction of rotation Clockwise (CW)
Number of autoclave cycles
Stefano, as long as you keep the motor speed below 1k you'll be fine. As Avwerk says, side loading and bearing wear on the motor will be your largest issue. But if you can keep the loading in the range of what a belt drive produces you should be fine.
As a raw concept rim drive should be a much more accurate solution in terms of speed stability than a floppy belt, but it introduces a whole load of physical constraints into the equation.
I'd still love to see a DD motor into a high drag bearing with speed control based purely on drive frequency.
As a raw concept rim drive should be a much more accurate solution in terms of speed stability than a floppy belt, but it introduces a whole load of physical constraints into the equation.
I'd still love to see a DD motor into a high drag bearing with speed control based purely on drive frequency.
Sq,
Our plan is to keep motor speed under 1K. As far as loading is concerned, I don’t know how to control that, it goes beyond my skill.
That is why I would like to see some mechanical discussion going on.
As far as DD is concerned, I personally strongly believe in D (If well implemented). Proven fact of its effectiveness is that VPI and other hi-end manufacturers are moving there.
It is certainly very expensive and hard to get it right (certainly harder than this project), but if a serious manufacturer invest time, resources and efforts on it, it is certainly going to be terrific.
Nevertheless, in order to have a DD you have to re-design your TT around it. This thread is more for an external accessory that everybody can use to convert their TT to as close as possible to a what we call DD without having to change their table.
However, I am going to post in a little bit, some preliminary dimensions (I did some studying last night) I estimated for the wheel, distances and everything.
Our plan is to keep motor speed under 1K. As far as loading is concerned, I don’t know how to control that, it goes beyond my skill.
That is why I would like to see some mechanical discussion going on.
As far as DD is concerned, I personally strongly believe in D (If well implemented). Proven fact of its effectiveness is that VPI and other hi-end manufacturers are moving there.
It is certainly very expensive and hard to get it right (certainly harder than this project), but if a serious manufacturer invest time, resources and efforts on it, it is certainly going to be terrific.
Nevertheless, in order to have a DD you have to re-design your TT around it. This thread is more for an external accessory that everybody can use to convert their TT to as close as possible to a what we call DD without having to change their table.
However, I am going to post in a little bit, some preliminary dimensions (I did some studying last night) I estimated for the wheel, distances and everything.
Stefano,
Just reviewing some of the specs for the Maxon motor.
The shaft of the DCX22L is only 3mm and the shaft is 10 mm long. This is a very small diameter shaft. I am sure we can make a pulley, but this is a much smaller shaft than typical motors. Typically the pulleys are secured to the shaft by a simple set screw. I think as the shaft gets smaller this is less effectve and the set screw might even bend the small diameter shaft, ever so slightly. Also, the set screw will tend to push the pulley away from being concentric with the shaft.
The 10 mm shaft is also short. The shaft must extend past the enclosure flange and into the pulley. Ideally the load on the motor shaft should be close to the motor bushings and not suspended on the end of shaft. We may need to extend the shaft with the pulley etc.
Also, the DXC22L is about 47mm long, not including the rear shaft clearance etc. This is a bit longer than most motors and may use up valuable height required for the enclosure, pulleys and flywheels.
After the motor is put into an enclosure, the enclosure has some feet, and then pulleys are added, the height of the pulley drive could be higher than ideal. The motor must also drive the flywheel BELOW the flywheel rim drive and the rim drive should not be higher than the CG of the platter. Even just 10mm in extra height of the motor could make things difficult.
Jamie
Just reviewing some of the specs for the Maxon motor.
The shaft of the DCX22L is only 3mm and the shaft is 10 mm long. This is a very small diameter shaft. I am sure we can make a pulley, but this is a much smaller shaft than typical motors. Typically the pulleys are secured to the shaft by a simple set screw. I think as the shaft gets smaller this is less effectve and the set screw might even bend the small diameter shaft, ever so slightly. Also, the set screw will tend to push the pulley away from being concentric with the shaft.
The 10 mm shaft is also short. The shaft must extend past the enclosure flange and into the pulley. Ideally the load on the motor shaft should be close to the motor bushings and not suspended on the end of shaft. We may need to extend the shaft with the pulley etc.
Also, the DXC22L is about 47mm long, not including the rear shaft clearance etc. This is a bit longer than most motors and may use up valuable height required for the enclosure, pulleys and flywheels.
After the motor is put into an enclosure, the enclosure has some feet, and then pulleys are added, the height of the pulley drive could be higher than ideal. The motor must also drive the flywheel BELOW the flywheel rim drive and the rim drive should not be higher than the CG of the platter. Even just 10mm in extra height of the motor could make things difficult.
Jamie
Attached is a more finalized design concept for new drive idea. This should give us all the mechanical basic information to start our discussion.
I considered a 50mm overlap for flywheel to reach out the platter. For example on my classic it is 42mm, so I am giving some more margin to accommodate more tables. I consider therefore 55mm to be what the flywheel will hang off by the pod (55 mm of clearance between motor pod and TT frame).
The assigned diameter for the wheel will be 140mm and calculated pulley diameter is 14mm. This allows us to run the selected motor at 700RPM at 33.333RPM and 945RPM at 45RPM. This values sets the rotation of the motor under 1K as sq recommended.
With 37.3RPM/nNm offers a good figure of 18.7mNm of torque at 33RPM and 25.3mNm of torque at 45RPM.
The low factors of RPM/V allows us plenty of headroom to control the motor.
Please let’s comment on this and see if we need to major adjustments or only minors to this mechanical concept.
Meanwhile, Pyramid and I have been entertaining some discussion on RPM’s optimization in order to maximize the resolution on the DAC control and feedback loop. Therefore perhaps, these figures might need to change slightly but I don’t expect any major change at least in order to run the controller properly.
My concern is to balance the pod and flywheel considering good part of the flywheel is hanging off the pod.
Anyhow, this is my thought: if we make the pod heavy enough to be stable and not being affected by the momentum of the heavy flywheel , we can extend dimension after the motor to keep the center of gravity in a safe spot, so I see possibilities to make these mechanical design fully stable.
I defer all the more specific comments to the mechanical guys and everybody else who wants to share their idea. No idea is stupid, if you have a though please throw it in as even if it doesn’t apply right in the second, might be applicable for other things we will need to get done.
My philosophy is, the more the ideas the better!
I considered a 50mm overlap for flywheel to reach out the platter. For example on my classic it is 42mm, so I am giving some more margin to accommodate more tables. I consider therefore 55mm to be what the flywheel will hang off by the pod (55 mm of clearance between motor pod and TT frame).
The assigned diameter for the wheel will be 140mm and calculated pulley diameter is 14mm. This allows us to run the selected motor at 700RPM at 33.333RPM and 945RPM at 45RPM. This values sets the rotation of the motor under 1K as sq recommended.
With 37.3RPM/nNm offers a good figure of 18.7mNm of torque at 33RPM and 25.3mNm of torque at 45RPM.
The low factors of RPM/V allows us plenty of headroom to control the motor.
Please let’s comment on this and see if we need to major adjustments or only minors to this mechanical concept.
Meanwhile, Pyramid and I have been entertaining some discussion on RPM’s optimization in order to maximize the resolution on the DAC control and feedback loop. Therefore perhaps, these figures might need to change slightly but I don’t expect any major change at least in order to run the controller properly.
My concern is to balance the pod and flywheel considering good part of the flywheel is hanging off the pod.
Anyhow, this is my thought: if we make the pod heavy enough to be stable and not being affected by the momentum of the heavy flywheel , we can extend dimension after the motor to keep the center of gravity in a safe spot, so I see possibilities to make these mechanical design fully stable.
I defer all the more specific comments to the mechanical guys and everybody else who wants to share their idea. No idea is stupid, if you have a though please throw it in as even if it doesn’t apply right in the second, might be applicable for other things we will need to get done.
My philosophy is, the more the ideas the better!
Attachments
Ok, I see your good points. Please take a look at my sketch and point out if there is any gross impediment. I used the height of my TT for reference, which is the very general purpose. Anyhow, the problem I see is to adjust it to different TTs. The feet should be adjustable, or even better feet can come in different sizes for instance, that could be a possible solution.
If this motor is really a problem we can try to find something else. I don’t know, but maxon offers for this motor different options as far as shaft and flange are concerned. I haven’t checked, but I am wondering if they offer a larger diameter. I will chek into that right now.
Please take a look at my sketch and give me some feedback. Thanks Jamie for your contribution, I feel we are doing a very good job so far.
checked. Unfortunately the diameter is fixed and we can only control the length.
I also checked the other motors maxon uses and shaft is even thinner. The "famous" A-Max that many high end manufacturer use is only 2mm diameter.
That said, we have to find a good way to make it work with 3mm.
I am thinking if the hole on the pulley is precise and fits like a glow, then 3 small screws will work just fine, I don't think much
I don't see many other choices as far as DC motors are concerned other than changing manufacturer for the motors, but researching around the Maxon are the absolute best. I think I mentioned that even the raving Kronos TT uses Maxon DC motor, have I? this should be a marginal guarantee of the quality of these DC motors.
I also checked the other motors maxon uses and shaft is even thinner. The "famous" A-Max that many high end manufacturer use is only 2mm diameter.
That said, we have to find a good way to make it work with 3mm.
I am thinking if the hole on the pulley is precise and fits like a glow, then 3 small screws will work just fine, I don't think much
I don't see many other choices as far as DC motors are concerned other than changing manufacturer for the motors, but researching around the Maxon are the absolute best. I think I mentioned that even the raving Kronos TT uses Maxon DC motor, have I? this should be a marginal guarantee of the quality of these DC motors.
Stefano,
Looks like the height and shaft dia. should not be a problem.
But, I feel like I am trying to run just to catch up with this project though and I'd like to see if we can revisit the basic goals. You are putting out a lot of your solutions before anyone else can really suggest anything different and we are all then trying to make your solution work or avoid making a criticism or suggesting something different.
I don't think the DIY community is really asking for a rim drive solution based on the feedback we are getting. Everyone is being very polite and offering their experience, but no one has said they also want a rim drive solution. This is just my reading of the feedback.
We are also not getting very much feedback or suggestions about DC motors. I believe this is because people do not want the rim drive and are afraid to disagree with you about that idea. I think, but I am not sure, that many people in the community might like a good, inexpensive, easy to build DC Motor and PSU solution. But, I think inexpensive and easy to build are important for DIY.
We haven't discussed a budget or any real price targets yet. The Maxon motors may be the best, but we're in the range of $250.00 just for the motor at this point, not including shipping. We're talking about machining enclosures from aluminum billet, flywheels, etc. and then control boards. This all adds up cost.
I think we should think about what the budget should be. If the entire kit is $1,000.00 then I don't think that is DIY. Maybe $500 is the limit, or that still might be too much for DIY.
To keep the budget reasonable for DIY, the configuration might need to be belt drive since that is the least expensive and easiest to build. If the solution works for belt drive, some people could also make a rim drive for themselves for more money.
But again, I am not really sure since this project is going in so many directions at one time. There is the decision for rim drive versus belt drive, decisions for AC versus DC motors, decisions about control logic and circuit topology. One person can easily make all these decisions for themselves and say "well this is just the best way because I say so", but I do not think a group of people can work on these decisions together if everything is happening at the same time quickly. People are really only able to agree or disagree, and then they must consider that to disagree is going against someone's strongly held belief.
I have not wanted to get involved in the debate about AC versus DC, or Rim Driver versus Belt Drive, or Digital Controller versus Discrete Controller, as I really don't know, but there should be some kind of consensus before we invest a lot of time in this. And this can't happen quickly. I believe you are trying to rush things because you believe this can be done quickly. All of my experience says that this is a 1 year project at a minimum. Unless, of course you do it by yourself and do not allow enough time for group working.
I will try to help as I can, and maybe someone else will be better to supply some mechanical solutions, and that is also okay, but my suggestion is to back up and focus the project on something with a budget and make sure the community is interested.
Jamie
Looks like the height and shaft dia. should not be a problem.
But, I feel like I am trying to run just to catch up with this project though and I'd like to see if we can revisit the basic goals. You are putting out a lot of your solutions before anyone else can really suggest anything different and we are all then trying to make your solution work or avoid making a criticism or suggesting something different.
I don't think the DIY community is really asking for a rim drive solution based on the feedback we are getting. Everyone is being very polite and offering their experience, but no one has said they also want a rim drive solution. This is just my reading of the feedback.
We are also not getting very much feedback or suggestions about DC motors. I believe this is because people do not want the rim drive and are afraid to disagree with you about that idea. I think, but I am not sure, that many people in the community might like a good, inexpensive, easy to build DC Motor and PSU solution. But, I think inexpensive and easy to build are important for DIY.
We haven't discussed a budget or any real price targets yet. The Maxon motors may be the best, but we're in the range of $250.00 just for the motor at this point, not including shipping. We're talking about machining enclosures from aluminum billet, flywheels, etc. and then control boards. This all adds up cost.
I think we should think about what the budget should be. If the entire kit is $1,000.00 then I don't think that is DIY. Maybe $500 is the limit, or that still might be too much for DIY.
To keep the budget reasonable for DIY, the configuration might need to be belt drive since that is the least expensive and easiest to build. If the solution works for belt drive, some people could also make a rim drive for themselves for more money.
But again, I am not really sure since this project is going in so many directions at one time. There is the decision for rim drive versus belt drive, decisions for AC versus DC motors, decisions about control logic and circuit topology. One person can easily make all these decisions for themselves and say "well this is just the best way because I say so", but I do not think a group of people can work on these decisions together if everything is happening at the same time quickly. People are really only able to agree or disagree, and then they must consider that to disagree is going against someone's strongly held belief.
I have not wanted to get involved in the debate about AC versus DC, or Rim Driver versus Belt Drive, or Digital Controller versus Discrete Controller, as I really don't know, but there should be some kind of consensus before we invest a lot of time in this. And this can't happen quickly. I believe you are trying to rush things because you believe this can be done quickly. All of my experience says that this is a 1 year project at a minimum. Unless, of course you do it by yourself and do not allow enough time for group working.
I will try to help as I can, and maybe someone else will be better to supply some mechanical solutions, and that is also okay, but my suggestion is to back up and focus the project on something with a budget and make sure the community is interested.
Jamie
Jamie,
Let’s skim things out. I feel you don’t want to really take part to this project. You have been trying to change motor type since the beginning without any real evidence that it would be more suitable than a DC motor for a low noise application. If your expertise is mechanical, you should have worried more about mechanical side and not worry so much about speed control, motor speed, torque and so on, when you have people like me and Pyramid work on it and when it is clearly not your field of expertise.
I am used to getting something started done and go through and not back up just because there are some difficulties on the path.
To be honest with you, I see a lot of people interested in this (just read the thread and you will see).
If you want s simple tube pad with a cheap motor, don’t even bother with this, as it does not belong to this thread and also, if you allow me, just use what you already have on your TT unless you have a very cheap table, but at that point the RIM drive would be a waste of your money either way.
Beside all other projects that I have going on right now, yet I am still taking the time to research and study things and producing a lot of work for the community and if you can’t catch up with things it cannot possibly be my fault, things sit there for days at a time without any comment so there is plenty of time there to comment and give inputs to the presented solution.
Also, I have been asking for mechanical advice since day one, considering especially that it is not my field of expertise but nobody has made any real effort so far.
I am sure the idea will work, but yes, you are correct with one thing, it won’t cost $300. Just the motor like you said is $200 alone. Then you will have PCB and controller and mechanical parts. I don’t know about this costs yet, so please don’t even ask. I don’t see it getting close to $1K at all. But all things considered for a vero supply and motor they are asking for $1700, not to mention the beloved TW motor and control.
I said from the beginning –READ-, the intent of this project is to create a TOP DC controller with RIM drive system! It is NOT belt and it NEVER CHANGED scope since the post started, maybe it did in your mind! You keep asking for things that are written in this really short thread that YOU can take the time to re-read and if you have any question ask for.
I don’t know how long it would take. Maybe one year? I don’t think so, but it takes the time it takes there is no real rush on it. Either way, you have to keep the peace if you want to get something done.
In short, you are obviously not interested in this, just say so and stay away from it and move on, nobody has forced you to take part of this.
I asked for people who were willing to work on THIS SPECIFIC job and you agreed, but I didn’t point any gun at you or did I? One thing is to not wanting to participate on something and another it to try to CHANGE completely the original scope of the project just because you don’t like it or it might cost YOU too much. Maybe you should open your own thread and project and work on controller and mechanical and everything, then maybe I can just participate and comment on it. I don’t think you need lots of help as you seem to have the key to the solution.
Here is the thing, if people are still interested in seeing this project done and to take part of it, please say so. If I see there is enough interest, I, at least on my side, will be willing to continue my researches and developments. If not, I will stop investing my time and energy on this.
All I need for it to continue, is a mechanical person who will pull through with prototypes of the mechanical parts and a SW which will continue with the design of the firmware and work closely with me on the prototype side (like Pyramid and I have been doing).
So far we had Pyramid and Ted. If you two are still ok to move forward, so will I and if there is interested we can continue.
On my side, I thought this was an interesting project and DIY doesn’t necessary mean to have to implement something basic and cheap. I think if there is the brain power and resources to do better, it is nice to see something excellent getting done. This is just my two cents.
Cheers!
Let’s skim things out. I feel you don’t want to really take part to this project. You have been trying to change motor type since the beginning without any real evidence that it would be more suitable than a DC motor for a low noise application. If your expertise is mechanical, you should have worried more about mechanical side and not worry so much about speed control, motor speed, torque and so on, when you have people like me and Pyramid work on it and when it is clearly not your field of expertise.
I am used to getting something started done and go through and not back up just because there are some difficulties on the path.
To be honest with you, I see a lot of people interested in this (just read the thread and you will see).
If you want s simple tube pad with a cheap motor, don’t even bother with this, as it does not belong to this thread and also, if you allow me, just use what you already have on your TT unless you have a very cheap table, but at that point the RIM drive would be a waste of your money either way.
Beside all other projects that I have going on right now, yet I am still taking the time to research and study things and producing a lot of work for the community and if you can’t catch up with things it cannot possibly be my fault, things sit there for days at a time without any comment so there is plenty of time there to comment and give inputs to the presented solution.
Also, I have been asking for mechanical advice since day one, considering especially that it is not my field of expertise but nobody has made any real effort so far.
I am sure the idea will work, but yes, you are correct with one thing, it won’t cost $300. Just the motor like you said is $200 alone. Then you will have PCB and controller and mechanical parts. I don’t know about this costs yet, so please don’t even ask. I don’t see it getting close to $1K at all. But all things considered for a vero supply and motor they are asking for $1700, not to mention the beloved TW motor and control.
I said from the beginning –READ-, the intent of this project is to create a TOP DC controller with RIM drive system! It is NOT belt and it NEVER CHANGED scope since the post started, maybe it did in your mind! You keep asking for things that are written in this really short thread that YOU can take the time to re-read and if you have any question ask for.
I don’t know how long it would take. Maybe one year? I don’t think so, but it takes the time it takes there is no real rush on it. Either way, you have to keep the peace if you want to get something done.
In short, you are obviously not interested in this, just say so and stay away from it and move on, nobody has forced you to take part of this.
I asked for people who were willing to work on THIS SPECIFIC job and you agreed, but I didn’t point any gun at you or did I? One thing is to not wanting to participate on something and another it to try to CHANGE completely the original scope of the project just because you don’t like it or it might cost YOU too much. Maybe you should open your own thread and project and work on controller and mechanical and everything, then maybe I can just participate and comment on it. I don’t think you need lots of help as you seem to have the key to the solution.
Here is the thing, if people are still interested in seeing this project done and to take part of it, please say so. If I see there is enough interest, I, at least on my side, will be willing to continue my researches and developments. If not, I will stop investing my time and energy on this.
All I need for it to continue, is a mechanical person who will pull through with prototypes of the mechanical parts and a SW which will continue with the design of the firmware and work closely with me on the prototype side (like Pyramid and I have been doing).
So far we had Pyramid and Ted. If you two are still ok to move forward, so will I and if there is interested we can continue.
On my side, I thought this was an interesting project and DIY doesn’t necessary mean to have to implement something basic and cheap. I think if there is the brain power and resources to do better, it is nice to see something excellent getting done. This is just my two cents.
Cheers!
yes, I believe you.
This is a project for who is interested in having and creating an excellent RIM drive to update the performance of their TT.
RIM drives are not cheap as everybody knows already, you need good mechanics, good motors and good controller. IMHO belts are preferred as there is much less work involved to get it right, better margins/profits associated as manufacturer can use a $30-40 motor and $2 silicon belt and $2 pulley and they are done and most of all no engineering involved.
I renew the interest here, people who want to go through with this project, see it done and actually use it, please say so. If there is enough interest we will be moving forward with this, otherwise not.
We will make sure it will be as cost effective as possible. Also, please, take in consideration the order of things, where a TT upgrade such as Vero drive or OL motor or Linn motor control they all cost way above $1000 some close to $2000 and they won't even come close to this implementation for motor control and quality of motor and mechanics.
We have no margins and no gains here so it will be as cheap as it gets and impossible to purchase something like this elsewhere at this price point.
Just something to think about it.
One more thing worth of mentioning on the pulley system, is that given the high ration from the motor to the platter which is about X21, the torque seen at the platter will be extremely high and more than capable to be independent of any stylus drag.
If on top of that we would put the extra momentum generated by the heavy flywheel, this is a system that will likely be load invariant to highly modulated grooves.
Just thought it was worth mentioning this technical aspect, since on one of my previous posts I mention that torque qs “only 18mNm at 33RPM, at the platter the torque will be 378mNm at 33RPM.
If on top of that we would put the extra momentum generated by the heavy flywheel, this is a system that will likely be load invariant to highly modulated grooves.
Just thought it was worth mentioning this technical aspect, since on one of my previous posts I mention that torque qs “only 18mNm at 33RPM, at the platter the torque will be 378mNm at 33RPM.
Stefanoo:
Keep on trucking !!! Don"t let anybody distract you from your goal. There has got to be more than one way to skin this cat!!!
The motor/controller is what will separate the great turntable from the ordinary. When you think about turntables in general, there are only so many Platter materials to use, only a few turntable bearing designs that work.
But getting that platter to spin perfectly at 33.3, 45, or 78 rmp is a whole different ball game.
I find a whole new respect for the TW motor /controller design. I am sure all the talent here can figure out a good reasonable solution that most analog lovers can afford.
Thanks again for your time trying to solve this decades long problem.
Keep on trucking !!! Don"t let anybody distract you from your goal. There has got to be more than one way to skin this cat!!!
The motor/controller is what will separate the great turntable from the ordinary. When you think about turntables in general, there are only so many Platter materials to use, only a few turntable bearing designs that work.
But getting that platter to spin perfectly at 33.3, 45, or 78 rmp is a whole different ball game.
I find a whole new respect for the TW motor /controller design. I am sure all the talent here can figure out a good reasonable solution that most analog lovers can afford.
Thanks again for your time trying to solve this decades long problem.
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