what was that??? I am not even sure I know you, but you don't have to participate on anything if you don't want to, nobody asked you in the first place!!!
The part about the O ring being precision ground and not touching when not in use is a very good observation.
With quite a few points actually touching while in use, it's going to be nearly impossible to have a lower overall noise than a good old belt.
The bearing will have more side thrust and will need more surface area to compensate.
I do like the idea of the "transmission" effect of the design and wish you the best, but be careful that you don,t take one step forward and two steps back.
Regards
David
With quite a few points actually touching while in use, it's going to be nearly impossible to have a lower overall noise than a good old belt.
The bearing will have more side thrust and will need more surface area to compensate.
I do like the idea of the "transmission" effect of the design and wish you the best, but be careful that you don,t take one step forward and two steps back.
Regards
David
Thank you so much for your very informative answer this really, really helps.
Before trying to answer to your key points, just keep in mind that, of course, somebody who is making TT has his own opinion and believes on what he does and things there is no other way and this might be true but that is why, we are all here, to discuss the best option available.
1) This might be true I have never compared RIM vs. belt but the extra quiet comes at a price which is called spring effect. As you attempt to reduce it, you attempt to remove this effect, you are creating a more rigid coupling and going back to the noise problem. I guess it is a matter of picking your worse evil and IMHO if the RIOM drive is designed quiet enough, your noise floor will never be above to your vinyl and phono stage.
2) Yes, this is a problem, the flywheel and pulley would have to be manufactured to a high precision and balanced. I am not a ME so I don’t know what are the processed involved, but I am sure it is doable in general, it is just a matter to know if we have the capabilities “on house” to do that. Remember for a manufacturer it’s all about costs and manufacturing something ultra precise means more rejected parts and therefore less margin on profits or higher price for the final parts which translates in less customers.
3) I saw this problem coming from a mile ahead, and that is why I said flat O-ring worked on lathe and milled down to the highest precision we have available, I don’t know how hard it is and again the ME guys should comment on the implementation aspect of it; nevertheless keep in mind that belts have the same exact problem and they are not specially milled, at least most of them.
4) This is actually an extremely good point! Thanks for sharing this. I think all you have to do after every session, is move your rim pod 1 cm away from the platter, disengage two/three screws off the flange of the motor and slide it away.
5) I agree with that, I don’t want to make the vintage people mad, but these tables are outdated. In the other hand, you would agree with me that if they are so popular, it is because there is probably a little truth on what they say! If the information we all read are true even fraction of what people say, it is not because of their plinth nor because of their platter nor spindle, but it is because they are direct or pulley or whatever and they are and will blow away for sure any cheap or even more advance modern belt drive system.
6) Here I don’t fully agree with you. I read reports of people who changed their system and upgraded it to the Vero supply or Vic direct drive and they were astounded how better it sounded and none them ever complained or even report anything about worsening their noise performance, if ever, they improved it!! And to mention one of the most famous names of the TT industry, VPI and their RIM drive. They are very good at what they do! The flywheel is in direct contact with the platter driven by two belt drive motors. People upgrade their tables with that and I don’t see any of them going back to belt drive. Moreover people then try the vero upgrade against the VPI RIM drive and they are blown away, why? Because there is no more belt involved! All this suggests me that the RIM drive is somehow superior to belt. I don’t know what TW acoustic does and why they do it, but there is a lot of information out there of people, way more informed and skilled, than you and I and they all seem to convey on the fact that the RIM drive is another animal. Moreover, still speaking of VPI, their latest and most expensive table, guess what, it is Direct Drive, so they must have understood that belt are not exactly the best thing in the world! Personally, I have deep respect for a serious manufacturer such as VPI, they make budget table such as my VPI Classic 3 that will blow TT much more expensive than that.
7) That I can’t say, you might be right I don’t know. Is there a way to establish if flywheel will bring benefit to the picture? Let’s see if we can reason on that (open discussion on this please as my logic could be faulty): flywheel is a passive device it is not powered up directly by the motor and this is an advantage. If we start from the assumption that the flywheel will be done balanced and made to high precision on a low noise/low friction spindle (please the ME guys can even say if we have the capabilities to do this?) and rubber coupled to the pulley and platter which is powered up by the motor and motor itself decoupled from the pad, the flywheel itself won’t have any loose parts therefore won’t have any wobbling, which is another advantage. Flywheel will also add a significant mass which will help with speed stability and dampening some more vibration, which is another advantage. Now, would this situation be worse than powering the platter up by a little pulley which is powered up directly by the spindle of a DC motor, which definitely doesn’t have tolerance like the flywheel? Is this going to be in any way quieter that the first approach? Maybe I am missing some practical sense as I don’t have in depth knowledge of driving systems, but logic would tell me that the flywheel would have an advantageous situation.
Please let’s comment on this as the intent here is to create the best drive system for people to upgrade their tables at a much lower price. You and I know how much the TW acoustic motor upgrade costs. We are talking about $5K and not so many people can afford that. Maybe this won’t be just as good as that or maybe it can be even better, but for sure, it won’t cost that much ! In the end, it will very likely be better than your current belt drive system, unless you probably own already a $30-40K or more TT.
I would develop and attentive listen to the solution on my reference system, which if some of the folks here are familiar with, has almost nothing to envy to any systems around, it is really top level. So if it works better than the belt I will definitely be able to tell and if in the end we decide to go for belt system, so be it. I am not stuck on any idea and that is why I opened up this post, so that we can discuss upfront the best solution and move then forward.
Thank you David. Do you mind explaining more the part on the bearing part?
Are you referring to the one on the platter or on the flywheel or both?
If I don't understand wrong, you are saying that the platter will be forced more on the side of its bearing maybe causing it to consume faster thus becoming noisier over time? Is this a real problem?
Also I don't quite understand the part where you say that RIM has less contact than a belt system (which I agree as the RIM will only contact at one point) therefore it has more noise transmitted! How can something which only has one point of contact be more prone to vibration than a system where there is more contact?
This is something I quite don't get it!
Stefanoo:
I very much hope to see a logical and reasonably priced motor/controller system come out of this thread.
I am definitely not stuck on a belt drive system. Perhaps VPI using modern technology and motor design has come up with a winner with direct drive. Time will tell. I am also sure the cost of a good motor/controller can be made so mere mortals can afford it.
Thomas ( TW acoustic ) has an open door policy when it comes to turntables. Bring in your turntable and he will set it up with the same arm and cartridge using the exact same speaker/electronics system ( $350,000- $400,000 I would guess ) and give a listen. Most all who do this wind up buying one of his turntables. Many of his customers have unlimited funds and own some very exotic equipment. Thomas is a perfectionist and will stop at nothing to make a better turntable. As I stated earlier, Thomas has owned/had on extended loan almost every top notch turntable out there and that includes the top Micro-Seki, EMT, and almost every thing in between and none performed better so far.
All this equipment/money is way too rich for my blood and that is why I am a DIY person. I am just lucky to know Thomas and be around this equipment to soak up the knowledge and great music during the audio shows.
I know that with all the talent here, something great will
I very much hope to see a logical and reasonably priced motor/controller system come out of this thread.
I am definitely not stuck on a belt drive system. Perhaps VPI using modern technology and motor design has come up with a winner with direct drive. Time will tell. I am also sure the cost of a good motor/controller can be made so mere mortals can afford it.
Thomas ( TW acoustic ) has an open door policy when it comes to turntables. Bring in your turntable and he will set it up with the same arm and cartridge using the exact same speaker/electronics system ( $350,000- $400,000 I would guess ) and give a listen. Most all who do this wind up buying one of his turntables. Many of his customers have unlimited funds and own some very exotic equipment. Thomas is a perfectionist and will stop at nothing to make a better turntable. As I stated earlier, Thomas has owned/had on extended loan almost every top notch turntable out there and that includes the top Micro-Seki, EMT, and almost every thing in between and none performed better so far.
All this equipment/money is way too rich for my blood and that is why I am a DIY person. I am just lucky to know Thomas and be around this equipment to soak up the knowledge and great music during the audio shows.
I know that with all the talent here, something great will
Well, pherhaps it will be hard to make it better than Thomas! He does it full time, spends money and time for research and prototype!! He is got money and set with the right equipment to do the job.
I highly doubt we will be able todo something like that, all I am asking for this is a very high quality drive that people will happily replace their original with.
If tip turns out to be even better than our expectations, great.
There area a lot of talented people on this forum and I hope we get he partecipation of many people to address our design concept.
For now, I will wait for thmechanical guys to comment on my model and let me know if my design concept can be manufactured.
If so, pyramid and I will move forward with the electronic side. We have been exchanging information today and we have very good ideas as far as the controller goes and I can ensure everybody that this controller will be the best on the market, I can at least guarantee that. As far as mechanical goes, I am no an ME, therefore it is all on the courts of our mechanical guys.
Please let me know how and if we want to proceed forward with this.
I highly doubt we will be able todo something like that, all I am asking for this is a very high quality drive that people will happily replace their original with.
If tip turns out to be even better than our expectations, great.
There area a lot of talented people on this forum and I hope we get he partecipation of many people to address our design concept.
For now, I will wait for thmechanical guys to comment on my model and let me know if my design concept can be manufactured.
If so, pyramid and I will move forward with the electronic side. We have been exchanging information today and we have very good ideas as far as the controller goes and I can ensure everybody that this controller will be the best on the market, I can at least guarantee that. As far as mechanical goes, I am no an ME, therefore it is all on the courts of our mechanical guys.
Please let me know how and if we want to proceed forward with this.
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I like to think of an idler as 1/2 way between a DD and belt drive.
With a belt you get a filter from motor vibrations ( belt ) and with DD you get direct motion with no filter.
What I am referring to is you have only a tight o ring revolving around 3 axis. And we haven,t even talked about mass ratios of all 3!
The motor bushings,rim bushings and platter bushing and these are rigid in the sense that vibration from all 3 bushings had better be near silent under load because the " filter " consists of a tight super glued o ring compared to a long belt that takes care of external motion.
Up until this point of construction, do you think you will have covered all these potential problems in comparison?
Have you made a low noise foundation that the diamond hasen,t noticed as of yet?
On top of that, all of this must be attached to the plinth in some way to make it work properly, read .,. Tight coupling. And at this point, have you awoke the diamond from its deep silent sleep? it doesn't take much since he's a light sleeper?
There is reason the simple belt drive has its advantages concerning external vibration, and rim drive would pose a serious challenge on that one issue alone.
I can appreciate that an in between "mass" might help to bury a serious bass transient at the blink of an eye, but usually a heavy platter has already passed by and hardly noticed?
I still leave room for persuasion because I haven,t done it yet and the emotional crowd has strong (Yoda) influence that drives concepts like these
I just can't think of the mechanism that would make me believe the emotional crowd is right as of yet..
However, Kate beckinsale handing me a Martini over this, might just convince me otherwise......
Regards
David
With a belt you get a filter from motor vibrations ( belt ) and with DD you get direct motion with no filter.
What I am referring to is you have only a tight o ring revolving around 3 axis. And we haven,t even talked about mass ratios of all 3!
The motor bushings,rim bushings and platter bushing and these are rigid in the sense that vibration from all 3 bushings had better be near silent under load because the " filter " consists of a tight super glued o ring compared to a long belt that takes care of external motion.
Up until this point of construction, do you think you will have covered all these potential problems in comparison?
Have you made a low noise foundation that the diamond hasen,t noticed as of yet?
On top of that, all of this must be attached to the plinth in some way to make it work properly, read .,. Tight coupling. And at this point, have you awoke the diamond from its deep silent sleep? it doesn't take much since he's a light sleeper?
There is reason the simple belt drive has its advantages concerning external vibration, and rim drive would pose a serious challenge on that one issue alone.
I can appreciate that an in between "mass" might help to bury a serious bass transient at the blink of an eye, but usually a heavy platter has already passed by and hardly noticed?
I still leave room for persuasion because I haven,t done it yet and the emotional crowd has strong (Yoda) influence that drives concepts like these
I just can't think of the mechanism that would make me believe the emotional crowd is right as of yet..
However, Kate beckinsale handing me a Martini over this, might just convince me otherwise......
Regards
David
Direct drive gets no filter because it does not need it. The motor is running at the lowest speed possible, 33rpm, about HALF hertz! Mechanically it's the simplest and the ONLY moving part in contact is the bearing. In a DD system, the motor and platter shares the same bearing and, in fact, the platter is part of the motor, the rotor. As far as filter is concerned, the magnetic field is the filter; it's a compliant system and it's design dependent, either tighter or looser. While a DD system has problems of its own such as cogging, bad servo, magnetic shielding, etc... motor noise is actually NOT one of them. Direct drive is a quiet system as long as its bearing is of high quality and that goes for ALL drive systems.
David,
Thanks for the constructive criticism.
Let me ask you something: have you ever heard of anybody on the net who has ever complained about the noise going from belt up to RIM drive? Somebody who's got the salvation whose complained about its noise? Somebody who's got a vpi rim drive and preferred the belt drive? Or somebody who has a vero drive which complained about noise?
I personally haven't!
All I know is that, hundreds people, commented positively being stunned by how much they gain by going to RIM drive.
Moreover, the fact that impacts me the most is that on all the comments reported, the user felt the background was quieter than with the belt(My guess is that they experience less distortion that the ear interprets as quieter musical signal which a classic effect of reducing distortion.)
All the systems I mentioned above are way cheaper quality than what we are, at least intent wise, trying to make.
Vero drive uses AC motor!!!! Vpi uses 2 AC motors. Salvation DC motor with super simple driving system.
I have people I know who have tried all 3 systems mentioned above and found the motor from the salvation to be the absolute best (accidentally happened to be DC motor).
Here we are planning on using the best DC motor in the market on a separate heavy pad, using a flywheel with very low noise and high mass with low noise/ low friction spindle and also milled o ring for maximum regularity! On top of this the best and most flexible controller audio market has yet to see.
Why would this be any noisier than the systems above mentioned?
Do you think we are missing something out from these commercial solutions? If so please bring it up on the plate and we can discuss it and address what we are missing.
My only concern would be if we have the capabilities and the resources to create a mechanical model that will be in pair with our expectations.
I don't know if I am wrong, but, as long as the mechanical guys have access to precision CNC and know how to use them, I don't think there should be any problem in making parts that are as precise as any other precision and machined part you find on delicate equipment
Please guys let me know if I am just fooling myself with this assumption, after all, my background is electronics and I am completely ignorant regarding machining and mechanical related topics.
Maybe, what I am thinking, is that we should cover more the construction aspect or in other words, how to make and design a proper low noise spindle and flywheel.
Unfortunately, this goes beyond my knowledge, so somebody here will have to step up and nudge us to the right direction.
Again, pyramid and I will be waiting for the mechanical implementation to get started to begin our SW and HW development.
It sounds like we should first consolidate the design concept and how we are going to design these parts for minimum noise.
Hope thus makes sense!
Thanks for the constructive criticism.
Let me ask you something: have you ever heard of anybody on the net who has ever complained about the noise going from belt up to RIM drive? Somebody who's got the salvation whose complained about its noise? Somebody who's got a vpi rim drive and preferred the belt drive? Or somebody who has a vero drive which complained about noise?
I personally haven't!
All I know is that, hundreds people, commented positively being stunned by how much they gain by going to RIM drive.
Moreover, the fact that impacts me the most is that on all the comments reported, the user felt the background was quieter than with the belt(My guess is that they experience less distortion that the ear interprets as quieter musical signal which a classic effect of reducing distortion.)
All the systems I mentioned above are way cheaper quality than what we are, at least intent wise, trying to make.
Vero drive uses AC motor!!!! Vpi uses 2 AC motors. Salvation DC motor with super simple driving system.
I have people I know who have tried all 3 systems mentioned above and found the motor from the salvation to be the absolute best (accidentally happened to be DC motor).
Here we are planning on using the best DC motor in the market on a separate heavy pad, using a flywheel with very low noise and high mass with low noise/ low friction spindle and also milled o ring for maximum regularity! On top of this the best and most flexible controller audio market has yet to see.
Why would this be any noisier than the systems above mentioned?
Do you think we are missing something out from these commercial solutions? If so please bring it up on the plate and we can discuss it and address what we are missing.
My only concern would be if we have the capabilities and the resources to create a mechanical model that will be in pair with our expectations.
I don't know if I am wrong, but, as long as the mechanical guys have access to precision CNC and know how to use them, I don't think there should be any problem in making parts that are as precise as any other precision and machined part you find on delicate equipment
Please guys let me know if I am just fooling myself with this assumption, after all, my background is electronics and I am completely ignorant regarding machining and mechanical related topics.
Maybe, what I am thinking, is that we should cover more the construction aspect or in other words, how to make and design a proper low noise spindle and flywheel.
Unfortunately, this goes beyond my knowledge, so somebody here will have to step up and nudge us to the right direction.
Again, pyramid and I will be waiting for the mechanical implementation to get started to begin our SW and HW development.
It sounds like we should first consolidate the design concept and how we are going to design these parts for minimum noise.
Hope thus makes sense!
Direct drive,
I know you are the most skilled person here on TT design. Would you be so kind to give us some insight on my design concept, if you think it could be a successful idea, if it is doable, manufacturable and if we should watch for some particular aspect we are missing?
I would really appreciate your critical opinion.
Thank you.
My feedback on the belts and rim drive. I would like to focus on just one aspect of the design in this post. Here are my thoughts. I have no experience doing this rim drive to a TT, so I am just thinking through this as best I can.
I believe the Idler Wheel must have the smallest force applied to the platter rim as possible since any run out or lack of concentricity of either the idler drive wheel OR the platter will result in bad things. Ideally, the contact between the idler wheel and platter is very small with some compliance.
There will be a coefficient of friction between the rubber material and the platter. The smaller the area of contact, the higher the pressure at contact. The force applied by friction is the same for a small contact area or large contact area. It does not matter for friction within the static friction range.
I think standard O-rings are the best for this. They come in many different sizes and materials. See this link just for the range of selection in Silcone O-rings.
McMaster-Carr
There are 11 different materials offered by McMaster in a wide range of sizes. We can test several to find the best one. DIY members can try their own and share which ones work best.
We'll precision machine the Idler Wheel.
Another option is to make the idler wheel from urethane. Urethane can be machined to some level of precision if it is first frozen in liquid nitrogen before machining. But, I doubt that urethane can be machined and then mounted to a hard shaft with better concentricity than machining a pulley from aluminum billet and then installing the O-ring. Sometimes simplier is better.
Jamie
I believe the Idler Wheel must have the smallest force applied to the platter rim as possible since any run out or lack of concentricity of either the idler drive wheel OR the platter will result in bad things. Ideally, the contact between the idler wheel and platter is very small with some compliance.
There will be a coefficient of friction between the rubber material and the platter. The smaller the area of contact, the higher the pressure at contact. The force applied by friction is the same for a small contact area or large contact area. It does not matter for friction within the static friction range.
I think standard O-rings are the best for this. They come in many different sizes and materials. See this link just for the range of selection in Silcone O-rings.
McMaster-Carr
There are 11 different materials offered by McMaster in a wide range of sizes. We can test several to find the best one. DIY members can try their own and share which ones work best.
We'll precision machine the Idler Wheel.
Another option is to make the idler wheel from urethane. Urethane can be machined to some level of precision if it is first frozen in liquid nitrogen before machining. But, I doubt that urethane can be machined and then mounted to a hard shaft with better concentricity than machining a pulley from aluminum billet and then installing the O-ring. Sometimes simplier is better.
Jamie
Oh, I forgot one key concept.
By using an O-ring with a very small contact area to the platter, any runout of the idler wheel or platter will compress the O-ring. With a small contact area the force that gets applied to the platter and idler wheel are minimized. If a large surface area is used for contact, there is very low pressure applied to the surface, but much higher force for variation of concentricity of the idler wheel and platter.
I am thinking the softest O-ring is best, but as I mentioned before, this can be solved by each person if they like as they try different materials. As the O-rings are compressed the absolute speed changes, but this is adjusted by the controller when setup and stays the same unless the motor pod is moved tighter.
Jamie
By using an O-ring with a very small contact area to the platter, any runout of the idler wheel or platter will compress the O-ring. With a small contact area the force that gets applied to the platter and idler wheel are minimized. If a large surface area is used for contact, there is very low pressure applied to the surface, but much higher force for variation of concentricity of the idler wheel and platter.
I am thinking the softest O-ring is best, but as I mentioned before, this can be solved by each person if they like as they try different materials. As the O-rings are compressed the absolute speed changes, but this is adjusted by the controller when setup and stays the same unless the motor pod is moved tighter.
Jamie
Oh, I forgot one key concept.
By using an O-ring with a very small contact area to the platter, any runout of the idler wheel or platter will compress the O-ring. With a small contact area the force that gets applied to the platter and idler wheel are minimized. If a large surface area is used for contact, there is very low pressure applied to the surface, but much higher force for variation of concentricity of the idler wheel and platter.
I am thinking the softest O-ring is best, but as I mentioned before, this can be solved by each person if they like as they try different materials. As the O-rings are compressed the absolute speed changes, but this is adjusted by the controller when setup and stays the same unless the motor pod is moved tighter.
Jamie
By using an O-ring with a very small contact area to the platter, any runout of the idler wheel or platter will compress the O-ring. With a small contact area the force that gets applied to the platter and idler wheel are minimized. If a large surface area is used for contact, there is very low pressure applied to the surface, but much higher force for variation of concentricity of the idler wheel and platter.
I am thinking the softest O-ring is best, but as I mentioned before, this can be solved by each person if they like as they try different materials. As the O-rings are compressed the absolute speed changes, but this is adjusted by the controller when setup and stays the same unless the motor pod is moved tighter.
Jamie
I really like your thinking here. I see you are very prepared to make educated decisions on your own on the mechanical side.
Let me ask you this: What do you need in order to feel confident and start manufacturing the wheel and pulley and enclosure.
Another question for you: How are you planning on making the enclosure? IMHO it is an extremely important part as it will have to act as a solid damping support.
Is it possible to have an aluminum block milled or you have a better idea?
Look at this thread :
http://www.diyaudio.com/forums/analogue-source/67089-corian-turntable-fun.html
There is another discussion about the enclosure.
http://www.diyaudio.com/forums/analogue-source/67089-corian-turntable-fun.html
There is another discussion about the enclosure.
Stefano,
I first want to make some calculations about pulley sizes based on rpm's. I would also like to see the motor shaft size. I'm really not sure the best approach for precision machining pulleys and how the belts or rim driving is best done without first seeing how the diameters interact.
There is no problem to make the enclosure from Aluminum, but Aluminum has no real advantage other than being easy and cheap. It has little mass and no vibration dampening. It does have good stiffness though.
For my personal equipment, I would use cast iron. But, I am not sure it is right for this.
I think we can start with the assumption that we'll use solid aluminum billet material, but maybe there is something better for mass.
Again, I'd like to see the dimensions of the motor shaft, the size of pulleys, etc.
Depending on the idler flywheel mass and the mass of the motor, we may have a problem getting the enclosure to have more mass. Consider that the flywheel will have a large amount of rotational inertia, the enclosure might be light as a feather in aluminum compared to the flywheel. Consider the flywheel will just jerk the enclosure around.
If the idea is that the enclosure has mass to resist vibration from the flywheel, etc. it might need to be heavy to really do that job, depending on flywheel mass.
I first want to make some calculations about pulley sizes based on rpm's. I would also like to see the motor shaft size. I'm really not sure the best approach for precision machining pulleys and how the belts or rim driving is best done without first seeing how the diameters interact.
There is no problem to make the enclosure from Aluminum, but Aluminum has no real advantage other than being easy and cheap. It has little mass and no vibration dampening. It does have good stiffness though.
For my personal equipment, I would use cast iron. But, I am not sure it is right for this.
I think we can start with the assumption that we'll use solid aluminum billet material, but maybe there is something better for mass.
Again, I'd like to see the dimensions of the motor shaft, the size of pulleys, etc.
Depending on the idler flywheel mass and the mass of the motor, we may have a problem getting the enclosure to have more mass. Consider that the flywheel will have a large amount of rotational inertia, the enclosure might be light as a feather in aluminum compared to the flywheel. Consider the flywheel will just jerk the enclosure around.
If the idea is that the enclosure has mass to resist vibration from the flywheel, etc. it might need to be heavy to really do that job, depending on flywheel mass.
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