Hello everyone!
I've been a bit quiet here lately.. Waiting for my D/A board to arrive and my drive gear(s) for my Theta Data.
BUT, I had an idea: I'm going to make a turntable!
I have read several threads on here (some QUITE long) and have a pretty good idea of what I'm going to do.
Bearing: I will probably make this myself. A beefy stainless shaft (1/2"-1" OD) running on a ceramic or sapphire ball in a brass sleeve (with Redline D4 ATF oil bath). The large diameter is for stability of the bearing yes; however it is also to allow me to close a collet on the shaft and use the actual shaft as the axis for turning the platen once the rough platen is attached to the shaft. This will ensure the platen is perpendicular to the shaft within 0.0005" or so, which I think will be good enough. I wish I had access to a dynamic balancing machine like the one used by the other shop next door to us in West Virginia!
Motor: I want to use a hall-effect servomotor. The quietest one I can find (as of now) is this one: http://www.teknic.com/files/product_info/1726_V3.3.pdf at $160.00 it is pretty cheap as well. I am open to any suggestions to alternate motors!
I think the platen should be MDF/Carbon fiber laminate. Looking now for carbon sheet (baked) as well as loose cloth, as I think wrapping the chassis with carbon will look cool.
Possible paring with Cocobolo, but that is WAY down the road.
Drive pulley will be simple brass. I can make it whatever diameter I need.
"belt" will be a nice o-ring
I am going to try and get some sink cut-outs of granite- black with some luck- and use that for the sub-base.
I am toying with the idea of suspending the mid-chassis with small air springs. They look like little shock absorbers. Three of those should isolate the top well, and it will be easy to adjust level with two of the three on some kind of threaded posts.
I am currently trolling eBay for tonearms, as I am not at a level to be making that! An RB300 would be fine; but certainly open to any and all suggestions!
So, let the games begin! I want to get the motor at least in hand before I go crazy making other items, only to find out the motor won't fit my intended design... So that is the priority right now!
Thanks in advance to all you big black disc players!
I've been a bit quiet here lately.. Waiting for my D/A board to arrive and my drive gear(s) for my Theta Data.
BUT, I had an idea: I'm going to make a turntable!
I have read several threads on here (some QUITE long) and have a pretty good idea of what I'm going to do.
Bearing: I will probably make this myself. A beefy stainless shaft (1/2"-1" OD) running on a ceramic or sapphire ball in a brass sleeve (with Redline D4 ATF oil bath). The large diameter is for stability of the bearing yes; however it is also to allow me to close a collet on the shaft and use the actual shaft as the axis for turning the platen once the rough platen is attached to the shaft. This will ensure the platen is perpendicular to the shaft within 0.0005" or so, which I think will be good enough. I wish I had access to a dynamic balancing machine like the one used by the other shop next door to us in West Virginia!
Motor: I want to use a hall-effect servomotor. The quietest one I can find (as of now) is this one: http://www.teknic.com/files/product_info/1726_V3.3.pdf at $160.00 it is pretty cheap as well. I am open to any suggestions to alternate motors!
I think the platen should be MDF/Carbon fiber laminate. Looking now for carbon sheet (baked) as well as loose cloth, as I think wrapping the chassis with carbon will look cool.
Possible paring with Cocobolo, but that is WAY down the road.Drive pulley will be simple brass. I can make it whatever diameter I need.
"belt" will be a nice o-ring
I am going to try and get some sink cut-outs of granite- black with some luck- and use that for the sub-base.
I am toying with the idea of suspending the mid-chassis with small air springs. They look like little shock absorbers. Three of those should isolate the top well, and it will be easy to adjust level with two of the three on some kind of threaded posts.
I am currently trolling eBay for tonearms, as I am not at a level to be making that! An RB300 would be fine; but certainly open to any and all suggestions!
So, let the games begin! I want to get the motor at least in hand before I go crazy making other items, only to find out the motor won't fit my intended design... So that is the priority right now!
Thanks in advance to all you big black disc players!
Hi Jim! Good luck with this. I keep thinking about doing a TT but seeing as how my vinyl collection is rather small I think my time is better spent playing around with a music server. Once upon a time I repaired TT's and still have a fascination with things that go round and round, especially when done well.
Watch out for cutting and grinding the carbon fiber materials - it can be nasty stuff to clean up and you will want some proper breathing gear.
Watch out for cutting and grinding the carbon fiber materials - it can be nasty stuff to clean up and you will want some proper breathing gear.
Actually, my small vinyl collection is one of the main driver's for this, believe it or not!
I would be quite happy with a Rega P3, but for the money, I thought I could make something quite nice- a true piece of art to behold while listening to CD's for example.
And, as to the carbon, I have worked with it before. It is VERY nasty stuff. Equally nasty is the epoxy used to hold the stuff together (I use West System). Good advice for those who have never worked with it however!
The cloth is a real pain to work with as it wants to stretch in every direction. I may stick with inlayed sheet pieces to complement the wood (or maybe aluminum) for the other components.
I suppose I will need a very stable power supply circuit with some adjust ability to 'dial in' the speed. I was thinking a momentary switch with a strobe would be neat- how many marks do I need around my platen to give a 60hZ strobe at 33.3 RPM? I think we have a Haas dividing head in the model shop, so I can rig that up once I turn the OD...
I have a lot of projects going on right now (wedding, house reconstruction etc.) but I want to do this. I am looking forward to any and all input as I get going on this!
I would be quite happy with a Rega P3, but for the money, I thought I could make something quite nice- a true piece of art to behold while listening to CD's for example.
And, as to the carbon, I have worked with it before. It is VERY nasty stuff. Equally nasty is the epoxy used to hold the stuff together (I use West System). Good advice for those who have never worked with it however!
The cloth is a real pain to work with as it wants to stretch in every direction. I may stick with inlayed sheet pieces to complement the wood (or maybe aluminum) for the other components.
I suppose I will need a very stable power supply circuit with some adjust ability to 'dial in' the speed. I was thinking a momentary switch with a strobe would be neat- how many marks do I need around my platen to give a 60hZ strobe at 33.3 RPM? I think we have a Haas dividing head in the model shop, so I can rig that up once I turn the OD...
I have a lot of projects going on right now (wedding, house reconstruction etc.) but I want to do this. I am looking forward to any and all input as I get going on this!
UPDATE:
I have done the plinth in MDF/birch ply laminated. The very core will be Lexan, which I hope to back-light so the table 'glows' when it is on. Should look cool!
I am designing my main bearing now. Probably another 3-4 hours designing, and then I can cut material.
I have found a DC motor that I like WAY overkill for this use, but better too big than too small. Should be ordering that this week or next.
I am going to make my tonearm 14.2" long, so an off the shelf arm will not do much other than give mt specific dimensions and design ideas. BUT, I am still looking for any and all unwanted tonearms (in any condition!)
It is going slow, but it is going. I hope to have this done by the end of the summer.
I have done the plinth in MDF/birch ply laminated. The very core will be Lexan, which I hope to back-light so the table 'glows' when it is on. Should look cool!
I am designing my main bearing now. Probably another 3-4 hours designing, and then I can cut material.
I have found a DC motor that I like WAY overkill for this use, but better too big than too small. Should be ordering that this week or next.
I am going to make my tonearm 14.2" long, so an off the shelf arm will not do much other than give mt specific dimensions and design ideas. BUT, I am still looking for any and all unwanted tonearms (in any condition!)
It is going slow, but it is going. I hope to have this done by the end of the summer.
Good progress Jim!! Would luv ta see sum photo's when you get things sorted out.
A couple of good sites to visit
The Crossover Network http://www.thecrossovernetwork.co.uk/forum/index.php
The Vinyl Engine Vinyl Engine | The Home of the Turntable
A couple of good sites to visit
The Crossover Network http://www.thecrossovernetwork.co.uk/forum/index.php
The Vinyl Engine Vinyl Engine | The Home of the Turntable
Thanks for those links!
I am registered and have a similar thread going over at the engine already. But, thanks for the link! To anyone else considering this project, that site has a TON of great information, and a lot of DIY table builders. Plus some very smart guys (not that we don't) who know more about table design and design considerations that I would have ever found otherwise!
Here's some pictures too!
First one is the first idea for the look. I cut some scrap material at 30 degrees back-angle to have the lexan recessed into the plinth. It looks cool, but the resultant sharp top edges seem too fragile, and will end up breaking off over time.
So, I have a new design I will mock up tonight.
Second photo is just the 20 X 20 pieces ready for additional work...
I am registered and have a similar thread going over at the engine already. But, thanks for the link! To anyone else considering this project, that site has a TON of great information, and a lot of DIY table builders. Plus some very smart guys (not that we don't) who know more about table design and design considerations that I would have ever found otherwise!
Here's some pictures too!
First one is the first idea for the look. I cut some scrap material at 30 degrees back-angle to have the lexan recessed into the plinth. It looks cool, but the resultant sharp top edges seem too fragile, and will end up breaking off over time.
So, I have a new design I will mock up tonight.
Second photo is just the 20 X 20 pieces ready for additional work...
Attachments
Almost a year later...
So the plinth has not progressed beyond what is shown above. Big surprise.
I have found and read more on turntable and tonearm design considerations than any human should have to endure. BUT, I have finalized the drawings of my (scratch built) tonearm- Version three- and I'm having parts made now (well, when he has time anyway). The arm will be carbon and OFC. It should look pretty nice!
The platen bearing was also scrapped in favor of a complete redesign (yet to be done). I want to use an inverted bearing, but recently learned quite a bit about proper platen design and intend to follow that. I also want it to be an oil-bathed inverted bearing, and making all that happen is a bit difficult with gravity being what it is and all (damn physics!)
So that's the update. Not much of one really, but I easily have 60-80 (part time) hours into the tonearm design, with a few components left to design.
So, sorry I've been away... I'm married now (almost a year already!) and have done a lot on the house (with no end in sight) It seems the more I fix, the more I find messed up. (climbing into the attic tonight to see what's up there...
So the plinth has not progressed beyond what is shown above. Big surprise.
I have found and read more on turntable and tonearm design considerations than any human should have to endure. BUT, I have finalized the drawings of my (scratch built) tonearm- Version three- and I'm having parts made now (well, when he has time anyway). The arm will be carbon and OFC. It should look pretty nice!
The platen bearing was also scrapped in favor of a complete redesign (yet to be done). I want to use an inverted bearing, but recently learned quite a bit about proper platen design and intend to follow that. I also want it to be an oil-bathed inverted bearing, and making all that happen is a bit difficult with gravity being what it is and all (damn physics!)
So that's the update. Not much of one really, but I easily have 60-80 (part time) hours into the tonearm design, with a few components left to design.
So, sorry I've been away... I'm married now (almost a year already!) and have done a lot on the house (with no end in sight)
It seems the more I fix, the more I find messed up. (climbing into the attic tonight to see what's up there...
So, sorry I've been away... I'm married now (almost a year already!) and have done a lot on the house (with no end in sight)
NOOOOOOOOOOOOOOOOOOOOOOO - NOT THE ATTIC!!!!
Goooooood ta see ya back Jim! Ahhhh.......... your progress speed matches mine nicely - still have a amp I built a year ago and need to get around to putting it into a case.............
Congrats on getting married. Did that myself almost 5yrs ago (second time around though). Can't wait to see more of your TT project.
Know all about household projects, my 100yr old house keeps me quite busy at times. Attic... <Shudder>
I'm less ambitious, restored a TD-124/ii a few months back. Listening to it now.. Amazing..
Know all about household projects, my 100yr old house keeps me quite busy at times. Attic... <Shudder>
I'm less ambitious, restored a TD-124/ii a few months back. Listening to it now.. Amazing..
guys, you're newbs (at marriage)
I've been lucky enough to have netted myself a keeper a while ago. I've been with the same girl 30 years (married for 25 of them).
Having this as a knowledge base, I can be certain of a few things:
Jim, good luck with the project (marriage). I'm sure it will fine. Just don't over-engineer it. (I asked my wife to look over the list, and of course she found fault---she suggested I follow my own advice. Busted, again!)
Regarding your turntable project, I am a believer in the K.I.S.S. principle. Sometimes we all forget that the point is to listen to music instead of designing stuff.
And remember that if, someone (you) were paying for the development time, then any economy is a false one.
I've been lucky enough to have netted myself a keeper a while ago. I've been with the same girl 30 years (married for 25 of them).
Having this as a knowledge base, I can be certain of a few things:
- She usually "wins" all of the arguments.
- A happy wife means a happy life.
- don't allow your audio "stuff" to interfere with any "decorating". The female homo sapiens sapiens loves the sound but hates the look.
- Never forget to give her good gifts with lots of unobtainium (er, ...like a new pre-amp when the time is right) for "special" occasions.
Jim, good luck with the project (marriage). I'm sure it will fine. Just don't over-engineer it. (I asked my wife to look over the list, and of course she found fault---she suggested I follow my own advice. Busted, again!)
Regarding your turntable project, I am a believer in the K.I.S.S. principle. Sometimes we all forget that the point is to listen to music instead of designing stuff.
And remember that if, someone (you) were paying for the development time, then any economy is a false one.
kevin (and Jim too):
well I'll just say that I really lucked out at a very early age (I'm 46 as I type this).
Jim, the engineering required to do a good "oil pump" type inverted bearing is not trivial (I know you didn't suggest that it was). For a start I'd suggest using a salvaged bearing/platter to get you going. Then if you like take the time to do a prototype, knowing that it may need to re-worked, or re-designed.
You may consider purchasing a unit that is pre-built, such as seen here. $115 + freight...
There may be others, but this seems like a pretty reasonable price.
well I'll just say that I really lucked out at a very early age (I'm 46 as I type this).
Jim, the engineering required to do a good "oil pump" type inverted bearing is not trivial (I know you didn't suggest that it was). For a start I'd suggest using a salvaged bearing/platter to get you going. Then if you like take the time to do a prototype, knowing that it may need to re-worked, or re-designed.
You may consider purchasing a unit that is pre-built, such as seen here. $115 + freight...
There may be others, but this seems like a pretty reasonable price.
Attachments
Thanks Stew, both for the marital advice and the bearing link.
I was initially going to use that very bearing (and the platter they offer- they also sell a decent motor package as well, making the project rather 'easy') but have learned that I would feel better if I made it rather than simply assembling it (I have no such ambitions when it comes to electronics, however).
So, an inverted bearing such as that is OK; however there is a great deal of surface area on the sides which allow the 'pump' to work. And, that pumping causes additional drag (above and beyond the increased surface area), which will slow the platter. And the better the pump works, the worse the drag, because the oil is pushed up, but is dead-ended. In fact, the oil could potentially trap an air bubble and then you'd have the disadvantage of oil drag without the advantage of oil! (but I doubt that would happen) plus how long does it have to run dry before oil finds its way between the bearing and thrust plate?
We need an inverted bearing, with the pivot just above the center of gravity of the platter, and bathed in oil. At the bottom of the bearing, the smallest 'guide' possible to keep the bearing straight. Like I eluded to earlier- the more I learn, the more I need to know...
Oh, and we need an opposing force opposite the drive motor (in the case of a belt drive) to offset the force of the drive belt. I have a unique idea for that that I have to attempt to implement (I've never seen my particular idea for this before). This also adds additional drag on the platter... And so it goes...
I was initially going to use that very bearing (and the platter they offer- they also sell a decent motor package as well, making the project rather 'easy') but have learned that I would feel better if I made it rather than simply assembling it (I have no such ambitions when it comes to electronics, however).
So, an inverted bearing such as that is OK; however there is a great deal of surface area on the sides which allow the 'pump' to work. And, that pumping causes additional drag (above and beyond the increased surface area), which will slow the platter. And the better the pump works, the worse the drag, because the oil is pushed up, but is dead-ended. In fact, the oil could potentially trap an air bubble and then you'd have the disadvantage of oil drag without the advantage of oil! (but I doubt that would happen) plus how long does it have to run dry before oil finds its way between the bearing and thrust plate?
We need an inverted bearing, with the pivot just above the center of gravity of the platter, and bathed in oil. At the bottom of the bearing, the smallest 'guide' possible to keep the bearing straight. Like I eluded to earlier- the more I learn, the more I need to know...
Oh, and we need an opposing force opposite the drive motor (in the case of a belt drive) to offset the force of the drive belt. I have a unique idea for that that I have to attempt to implement (I've never seen my particular idea for this before). This also adds additional drag on the platter... And so it goes...
ok,
well you could always make a rim drive and then it doesn't matter.
One thing that lots of folks usually don't take into consideration is the drag caused by the oil, a point well stated. And surface area is a critical as well.
I like the idea that Roksan used in the Xerxes: a long, thin bearing at a quite small diameter. And they also addressed tension in the belt, allowing the motor to rotate , but held at a constant force by a spring.
One way I've thought that could be implemented would be to use an idler pulley (much like an automotive belt tensioner, where the tension can be adjusted and that it will keep it constant based on using a spring attached to the tensioner arm.
Regarding the tonearm, how about a Nanook 219? Cheap and (methinks) quite good.
well you could always make a rim drive and then it doesn't matter.
One thing that lots of folks usually don't take into consideration is the drag caused by the oil, a point well stated. And surface area is a critical as well.
I like the idea that Roksan used in the Xerxes: a long, thin bearing at a quite small diameter. And they also addressed tension in the belt, allowing the motor to rotate , but held at a constant force by a spring.
One way I've thought that could be implemented would be to use an idler pulley (much like an automotive belt tensioner, where the tension can be adjusted and that it will keep it constant based on using a spring attached to the tensioner arm.
Regarding the tonearm, how about a Nanook 219? Cheap and (methinks) quite good.
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Well, actually even with an idler (either vertical or horizontal), it applies an outside force (besides the rotational one) that should (ideally) be countered to keep the main bearing 'centered' and well balanced.
Well like I said. the more I learn, the more I find I need to know. An entire thread could be devoted to oil viscosity at temperatures, shear strength of synthetic vs. Dino oil etc...... Plus there is bearing rumble as the bearing shaft rubs the shell; the larger the diameter of the bearing, the more surface area can rub, and therefore the more rumble potential from the bearing...
When I was assuming to use a typical bearing, I was planning on a thin, solid carbide shaft (for stifness)...
I put a lot of thought into this idea. Since I need a belt that won't stretch (so it does not store energy and feed into wow), I need a way to provide 'enough' tension to allow the motor to spin the platen; but not 'too' much that will pull the bearing to one side too much... I thought about another scheme to do that as opposed to the 'belt tensioner'. And, if the belt is wide (ala VHS tape) there is a static build up potential as well as increased surface area, for increased sound generation potential.
Regarding the tonearm, how about a Nanook 219? Cheap and (methinks) quite good.
I am not familiar with that tonearm... Mine is 14.215 effective length. I found one German company making a 14" arm, but that was the only one I found... (and I have no hope to ever afford it either)
Uni-pivots....
yup a uni. Dumb stupid and simple. It competes with my SME309 easily. Same league, different presentation.
Have a look at this thread for details.
Not trying to discourage you, if you have the resources to get your arm machined, great. My "219" requires no outside machine work.
yup a uni. Dumb stupid and simple. It competes with my SME309 easily. Same league, different presentation.
Have a look at this thread for details.
Not trying to discourage you, if you have the resources to get your arm machined, great. My "219" requires no outside machine work.
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