An other DIY Schröder Tonearm Project
Hi. I'm just starting this new thread while we (me and Kilowattski) are starting an other crazy endeavor. I just completed my own Teres turntable (see the details at http://www.diyaudio.com/forums/showthread.php?s=&threadid=109561&perpage=25&pagenumber=1) with Mark Kelly controller (http://www.diyaudio.com/forums/showthread.php?s=&threadid=98045&perpage=25&pagenumber=1), and then Kilowattski contacted me and asked if I was interested in trying to build a Schroeder Tonearm clone.
I was already involved with Greg Nuspel (the nice guy that help us with the controller pulley design and manufacturing), but then Greg move along to some other projects. I was left without a machinist, so the project was out of the question. But I collected bits and pieces for the tonearm, found a nice tonearm lifter from Germany, etc, so it was a shame to let it go. Kilowattski made my day when he asked if I was interested in the project again. I certainly was
Don't take it wrong. Me and Kilowattski, we don't pretend that we can we do as good a tonearm as the real Schroeder (or even to get close to a good tonearm to start with), but we thought it would be a fun project.
We did a lot of research (published US patent, publicly accessible information and photos) and thinking, use some of the nice ACAD concept that Greg originally produced, and Kilowattski did a great job at producing a first draft design (in virtual CAD reality at least).
This thread will show our progress (or lack of) as we go along building the arm. Comments are welcome.
First, disclaimer right from the start. Yes, we are trying to build a Schröder Clone, but with a few twists. it may have a micrometer VTA adjustment for example. We don't have access to the real thing, and we don't know the trade secret of Mr. Frank Schroeder, and we are not trying to discover them either. Purpose of this project is real DIYer work, try to get something that work and have fun in the process. We are not trying to start a production of cheap copies or to steal any body's work. So, it won't be a real Schröder tonearm, just our own version of a great design using magnetic bearing, thread pivot point, etc...
I contacted Mr. Schroeder himself by email and asked for his permission to use his design concept and show our work and findings (username berlinta, he posted on the very forum at some occasions). He kindly reply and gives us permission with some restrictions. He even offer some comments and suggestions that can help us get a better result. That was very generous, and we can only thank him for doing so.
His reply was: ''I have no objections to you and your friend building your own Schröder arm version and sharing it with other DIYers a long as you don't publish drawings that someone else could use as a basis for a commercial effort. Photograps are fine off course.''
So, we will go along within these restrictions. That means, don't ask for ACAD drawings or files on our design, on this thread or by private email. I can just refer you back to designer itself.
I'll post some pictures and comments on the project.
Updates will be posted soon, I hope. So stay tuned.
Hi. I'm just starting this new thread while we (me and Kilowattski) are starting an other crazy endeavor. I just completed my own Teres turntable (see the details at http://www.diyaudio.com/forums/showthread.php?s=&threadid=109561&perpage=25&pagenumber=1) with Mark Kelly controller (http://www.diyaudio.com/forums/showthread.php?s=&threadid=98045&perpage=25&pagenumber=1), and then Kilowattski contacted me and asked if I was interested in trying to build a Schroeder Tonearm clone.
I was already involved with Greg Nuspel (the nice guy that help us with the controller pulley design and manufacturing), but then Greg move along to some other projects. I was left without a machinist, so the project was out of the question. But I collected bits and pieces for the tonearm, found a nice tonearm lifter from Germany, etc, so it was a shame to let it go. Kilowattski made my day when he asked if I was interested in the project again. I certainly was
Don't take it wrong. Me and Kilowattski, we don't pretend that we can we do as good a tonearm as the real Schroeder (or even to get close to a good tonearm to start with), but we thought it would be a fun project.
We did a lot of research (published US patent, publicly accessible information and photos) and thinking, use some of the nice ACAD concept that Greg originally produced, and Kilowattski did a great job at producing a first draft design (in virtual CAD reality at least).
This thread will show our progress (or lack of) as we go along building the arm. Comments are welcome.
First, disclaimer right from the start. Yes, we are trying to build a Schröder Clone, but with a few twists. it may have a micrometer VTA adjustment for example. We don't have access to the real thing, and we don't know the trade secret of Mr. Frank Schroeder, and we are not trying to discover them either. Purpose of this project is real DIYer work, try to get something that work and have fun in the process. We are not trying to start a production of cheap copies or to steal any body's work. So, it won't be a real Schröder tonearm, just our own version of a great design using magnetic bearing, thread pivot point, etc...
I contacted Mr. Schroeder himself by email and asked for his permission to use his design concept and show our work and findings (username berlinta, he posted on the very forum at some occasions). He kindly reply and gives us permission with some restrictions. He even offer some comments and suggestions that can help us get a better result. That was very generous, and we can only thank him for doing so.
His reply was: ''I have no objections to you and your friend building your own Schröder arm version and sharing it with other DIYers a long as you don't publish drawings that someone else could use as a basis for a commercial effort. Photograps are fine off course.''
So, we will go along within these restrictions. That means, don't ask for ACAD drawings or files on our design, on this thread or by private email. I can just refer you back to designer itself.
I'll post some pictures and comments on the project.
Updates will be posted soon, I hope. So stay tuned.
Come on Ladies and Gents. Where is the interest? Sylvain (Algar_emi) and I will be tag-teaming this one. We will be making the last of the drawing changes tommorrow and the first machining starts Saturday. I promise to take as many pictures as I can. My goal is to machine a part a week. I am taking my time because I am not an experienced machinist. I am a beginner and like to measure everything two or three times before taking mill or lathe to material. It's gonna be alot of fun and Sylvain (Algar_emi) and I should a couple of Schroeder Clones out of it. I want to send a special thank you to Frank Schroeder for looking our drawings over and making suggestions.
PS: We are adding a little surprise to our Schroeder Clone. We will be adding micrometer based VTA on the fly. It should be very interesting to say the least.
PS: We are adding a little surprise to our Schroeder Clone. We will be adding micrometer based VTA on the fly. It should be very interesting to say the least.
kilo,
I'm very interested in seeing how this progresses and I would love to participate. However, I believe most of us will likely be confined to the sidelines. I'm no machinist and even if I were, it would be nearly impossible to join in the fun without drawings.
To me this is like trying to build a circuit without a schematic......
Bill
I'm very interested in seeing how this progresses and I would love to participate. However, I believe most of us will likely be confined to the sidelines. I'm no machinist and even if I were, it would be nearly impossible to join in the fun without drawings.
To me this is like trying to build a circuit without a schematic......
Bill
MashBill said:kilo,
I'm very interested in seeing how this progresses and I would love to participate. However, I believe most of us will likely be confined to the sidelines. I'm no machinist and even if I were, it would be nearly impossible to join in the fun without drawings.
To me this is like trying to build a circuit without a schematic......
Bill
Bill,
I would love to post the drawings, but Frank Schroeder has asked us not to. He has been very helpful and Sylvain and I will honor his wishes. I came up with the drawings by looking at pictures of the Schroeder Reference Arm and gestimating the dimensions via proportion, looking at his patent and trial and error. AutoCad made the job a little easier. I am no machinist. I just have access to a machine shop on the weekends and enough knowledge to make me dangerous. I am a beginner. Now if I had Vinyl Addicts skills, it would be done already. You should see the turntable he made. I loosely based my turntable on his design. I will post as many pictures of the Arm as work progresses.
Guy
woodturner-fran said:
Fran,
On the Schroeder Arm, it was a very simple thing to do. No earth shattering design breakthroughs here. Frank as a very nice implementation of VTA adjustment already in the Schroeder Reference Arm but ours will work on the fly. We will use a simple Starrett 0 to 0.5 inch micrometer head.
PS: We are making the arm tube out of Carbon Fiber. If I had your turning skills it would be made of some kind of exotic wood.
Have you considered rolling your own?
You can buy all manner of types of wood in fine veneers at 1/28 of an inch thick, sanded smooth both sides. Fashion a form any way you like in any shape you like. A little masking tape and a little white wood glue (PVA). Fix one end or the veneer to the form and roll away finish off with a fine line of PVA and a layer of tape let dry 30 minutes. Trim the excess veneer and remove the wooden tube from the form. Now you have a thin wall wooden tube straight walled or tapered. You could fill the tube with expanding poly foam if you like. Experiment all you want the tubes cost almost nothing and take minutes to make. You could use a bunch of paper straws as a base core for a tube which would be light and strong and keep things totally organic. Hope this gives you some options. You might also consider using a bread stick as an arm tube no kidding organic wheat foam core hard crust skin. There are also the super light white hard open cell foams used in craft work that can also make a foam core to veneer over. You could also build the whole thing out of rice paper or similar. Have fun.
You can buy all manner of types of wood in fine veneers at 1/28 of an inch thick, sanded smooth both sides. Fashion a form any way you like in any shape you like. A little masking tape and a little white wood glue (PVA). Fix one end or the veneer to the form and roll away finish off with a fine line of PVA and a layer of tape let dry 30 minutes. Trim the excess veneer and remove the wooden tube from the form. Now you have a thin wall wooden tube straight walled or tapered. You could fill the tube with expanding poly foam if you like. Experiment all you want the tubes cost almost nothing and take minutes to make. You could use a bunch of paper straws as a base core for a tube which would be light and strong and keep things totally organic. Hope this gives you some options. You might also consider using a bread stick as an arm tube no kidding organic wheat foam core hard crust skin. There are also the super light white hard open cell foams used in craft work that can also make a foam core to veneer over. You could also build the whole thing out of rice paper or similar. Have fun.
Hello every folks!
First ill introduce my self. I am a student from the Netherlands.
For my educational programme i have a part which i can fill in at my one wishes (within borders of course).
I have chosen to construct a tone arm. Of course i had to chose a type of tone arm. After a small research I made up my mind and chose the Schroeder type bearing.
In the meanwhile i have read the topics about the diy tone arm on this forum. But i still heave some questions that needs to be answered.
There for I taught to get the email address from mr. Schroeder from this forum. no no said this forum. you first have to write some posts because your new
There for i will spam this topic kidding.
In the older topic about this tone arm mr Schroeder wrote about a big problem.,The chancing of the VTF and VTA during playing. In particular with non-planar plates.
I think the mean problem with this issue is that the tone arm is moving out of the vertical bearing axis.
One thing that might help is a conical hole in the upper magnet, (a large diameter hole at the top of the magnet, and a small diameter hole at the bottom)
Besides this a spherical lower magnet wil be necessary. Because he wrote that the force is the highest at the edge of the magnet.
I think that this wil prevent the tonearm from moving out of the vertical axis.
Fore more magnet strengt the lower magnet can by quite high i think.
I hope that my view makes some sense to you all.. if not, please let me know.
Note: I have no commercial ideas of what so ever. (pure edicational and hobby. )
First ill introduce my self. I am a student from the Netherlands.
For my educational programme i have a part which i can fill in at my one wishes (within borders of course).
I have chosen to construct a tone arm. Of course i had to chose a type of tone arm. After a small research I made up my mind and chose the Schroeder type bearing.
In the meanwhile i have read the topics about the diy tone arm on this forum. But i still heave some questions that needs to be answered.
There for I taught to get the email address from mr. Schroeder from this forum. no no said this forum. you first have to write some posts because your new
There for i will spam this topic
kidding. In the older topic about this tone arm mr Schroeder wrote about a big problem.,The chancing of the VTF and VTA during playing. In particular with non-planar plates.
I think the mean problem with this issue is that the tone arm is moving out of the vertical bearing axis.
One thing that might help is a conical hole in the upper magnet, (a large diameter hole at the top of the magnet, and a small diameter hole at the bottom)
Besides this a spherical lower magnet wil be necessary. Because he wrote that the force is the highest at the edge of the magnet.
I think that this wil prevent the tonearm from moving out of the vertical axis.
Fore more magnet strengt the lower magnet can by quite high i think.
I hope that my view makes some sense to you all.. if not, please let me know.
Note: I have no commercial ideas of what so ever. (pure edicational and hobby.
)Yet another Schroeder arm
Hi DIYers,
I am Bill Gruhn in Massachusetts. I am a retired engineer and an audio DIYer of very long standing. Recently started converting an old DIY Well tempered arm to a Schroeder design. First off I did a quick replacement of all the silicone oil suspension parts with the two magnets, adapting them directly to the suspension disk of the WTA. I then converted the WTA double strings arrangement to Schroeder's split string setup making my old arm very like a Model 1 Schroeder. There were several things that needed refinement but rather than digging in to that, I decided to try the single string setup of the Model 2, mostly because I like the looks of the design better if all else be equal. The first attempt really had great sound though.
On to the single string Model 2. It has been playing very nicely albeit with a few problems to sort out before making a pretty one. The magnets are generic Neodymium disc magnets from the hardware store measuring 8 mm x 3 mm. No idea what strength but they sure are hard to get apart when stuck together. Will be ordering some good ones soon. There is a problem I would like to get a bit of help with please. The bottom magnet is just recessed into the 1/4" diam aluminum arm tube. and drilled out for the string which goes up through a hole in the top of the arm tube and on up to the upper support. member. Pardon if I don't use the exact nomenclature, but it should be clear. Now with the arm assembled and roughly balanced I find that it rotates on its long axis flipping so either side of the upper tube hole is resting firmly against the string. In the manner of an over-the-center spring or toggle. The assembly looks just like the pictures of the actual Schroeder arm so I do not think there is a gross geometry error, but it sure acts like there is. In Frank Schroeder's Model 2 manual he mentions using a drop or three of silicone oil applied to the string and allowed to run down into the well in the arm tube. Well I don't have a well yet, but very thick silicone oil doesn't begin to fix this one. What does work beautifully is to anchor arm tube to the string with a small drop of hot glue centering the string in the little hole. As near as I can tell the actual pivot point is still at or below the bottom surface of the top magnet and the stability of the thing is great. One of the close up photos of the model 2 (on the www.soundscapehifi.com/schroder-model2-pics.htm ) web site shows the hole and string with something just below the surface of the arm tube. If there is something inside the tube anchoring the string/tube then that is Schroeder's solution. But, if that is the case, putting silicone oil at that spot seems to be somewhat of a futile gesture, what looks like a "well" is so tiny as to provide no effective damping especially of any cartridge/arm tube resonances.
The little drop could do some minor damping of the string itself. Can someone please give me an explanation or show me what I am missing.
Thanks,
Bill
Hi DIYers,
I am Bill Gruhn in Massachusetts. I am a retired engineer and an audio DIYer of very long standing. Recently started converting an old DIY Well tempered arm to a Schroeder design. First off I did a quick replacement of all the silicone oil suspension parts with the two magnets, adapting them directly to the suspension disk of the WTA. I then converted the WTA double strings arrangement to Schroeder's split string setup making my old arm very like a Model 1 Schroeder. There were several things that needed refinement but rather than digging in to that, I decided to try the single string setup of the Model 2, mostly because I like the looks of the design better if all else be equal. The first attempt really had great sound though.
On to the single string Model 2. It has been playing very nicely albeit with a few problems to sort out before making a pretty one. The magnets are generic Neodymium disc magnets from the hardware store measuring 8 mm x 3 mm. No idea what strength but they sure are hard to get apart when stuck together. Will be ordering some good ones soon. There is a problem I would like to get a bit of help with please. The bottom magnet is just recessed into the 1/4" diam aluminum arm tube. and drilled out for the string which goes up through a hole in the top of the arm tube and on up to the upper support. member. Pardon if I don't use the exact nomenclature, but it should be clear. Now with the arm assembled and roughly balanced I find that it rotates on its long axis flipping so either side of the upper tube hole is resting firmly against the string. In the manner of an over-the-center spring or toggle. The assembly looks just like the pictures of the actual Schroeder arm so I do not think there is a gross geometry error, but it sure acts like there is. In Frank Schroeder's Model 2 manual he mentions using a drop or three of silicone oil applied to the string and allowed to run down into the well in the arm tube. Well I don't have a well yet, but very thick silicone oil doesn't begin to fix this one. What does work beautifully is to anchor arm tube to the string with a small drop of hot glue centering the string in the little hole. As near as I can tell the actual pivot point is still at or below the bottom surface of the top magnet and the stability of the thing is great. One of the close up photos of the model 2 (on the www.soundscapehifi.com/schroder-model2-pics.htm ) web site shows the hole and string with something just below the surface of the arm tube. If there is something inside the tube anchoring the string/tube then that is Schroeder's solution. But, if that is the case, putting silicone oil at that spot seems to be somewhat of a futile gesture, what looks like a "well" is so tiny as to provide no effective damping especially of any cartridge/arm tube resonances.
The little drop could do some minor damping of the string itself. Can someone please give me an explanation or show me what I am missing.
Thanks,
Bill
Hi Bill,
Sorry, the choice of magnet(dimensions) explains the "error" in the behaviour of your bearing. Try 8x5mm...or a counterweight with a very low center of gravity(not ideal). But this isn't the whole story.
The "well", once (partially) filled with silicone fluid will have a profound influence on the damping of the arm cartridge res frequency peak, but predominantly for vertical movement. It's not to "fix" any instability. This bearing, as said earlier, can be made to behave anything from stable to unstable.
And that means, sorry again, that livemusic's assessment is INCORRECT! I have built arms without low slung counterweights with a restoring force of zero, but also some with a rf up to as much as 0,5gr per 10° deviation from equilibrum.
Lastly the bearing can be executed so that it is stable around the armwand axis and neutral for vertical(up-down) movement. But that can't be done with disc shaped magnets
Cherio,
Frank
Sorry, the choice of magnet(dimensions) explains the "error" in the behaviour of your bearing. Try 8x5mm...or a counterweight with a very low center of gravity(not ideal). But this isn't the whole story.
The "well", once (partially) filled with silicone fluid will have a profound influence on the damping of the arm cartridge res frequency peak, but predominantly for vertical movement. It's not to "fix" any instability. This bearing, as said earlier, can be made to behave anything from stable to unstable.
And that means, sorry again, that livemusic's assessment is INCORRECT! I have built arms without low slung counterweights with a restoring force of zero, but also some with a rf up to as much as 0,5gr per 10° deviation from equilibrum.
Lastly the bearing can be executed so that it is stable around the armwand axis and neutral for vertical(up-down) movement. But that can't be done with disc shaped magnets
Cherio,
Frank
Frank,
Thank you very much for the reply. As I mentioned the magnets I used were found in the local hardware store and looked to be usable. That is what started this project. I am ordering some from an in-line vendor that though in inch sizes are but a few thousandths away from the metric dimensions. I'll try them with soft iron or mild steel pole pieces of various contours.
Would you care to comment on fixing the attachment point of the thread to the top of the arm tube with something, perhaps a dot of hot glue as I mentioned in my first post? This was very successful for stabilizing the arm tube.
In yet another approach, I did a variation of the Model-1 inverted Y suspension which also appears to be very successful. I drilled the arm tube on its horizontal centerline all the way through the opposite side wall. Then passed a thread all the way through the arm tube, brought it around to the top, tied a knot just above the arm tube, about 13 mm above the tube. Cut off one of the thread tails and passed the remaining tail up through the top support. This gave me a miniature inverted Y suspension. On casual listening over a few evenings I have found little to complain about.
One last question if the answer is not a trade secret, The "well" we have mentioned before, Is that an actual physical structure separated from the rest of the arm tube interior or is it just the small space defined by the thickness and diameter of the hole in the arm tube?
I give you my sincerest thanks for helping me and all the other DIYers building their Schroeder inspired tone arms.
Bill
Thank you very much for the reply. As I mentioned the magnets I used were found in the local hardware store and looked to be usable. That is what started this project. I am ordering some from an in-line vendor that though in inch sizes are but a few thousandths away from the metric dimensions. I'll try them with soft iron or mild steel pole pieces of various contours.
Would you care to comment on fixing the attachment point of the thread to the top of the arm tube with something, perhaps a dot of hot glue as I mentioned in my first post? This was very successful for stabilizing the arm tube.
In yet another approach, I did a variation of the Model-1 inverted Y suspension which also appears to be very successful. I drilled the arm tube on its horizontal centerline all the way through the opposite side wall. Then passed a thread all the way through the arm tube, brought it around to the top, tied a knot just above the arm tube, about 13 mm above the tube. Cut off one of the thread tails and passed the remaining tail up through the top support. This gave me a miniature inverted Y suspension. On casual listening over a few evenings I have found little to complain about.
One last question if the answer is not a trade secret, The "well" we have mentioned before, Is that an actual physical structure separated from the rest of the arm tube interior or is it just the small space defined by the thickness and diameter of the hole in the arm tube?
I give you my sincerest thanks for helping me and all the other DIYers building their Schroeder inspired tone arms.
Bill
reost #15
Hello Schröder tone arm fans,
I thought I had successfully posted this note last night but It appears something went wrong. If tonight's post is a duplicate (more or less) Mr Moderator please delete this one. Thank you.
Post #15 discusses my progress making a Schröder inspired tone arm and mentions an alternate inverted Y design I put together for test and experiment work. For some more information and photos of this version as well as photos of my DIY turntable using Corian for plinth, base and platter, and the WTA clone I am expecting to replace with a version of either the inverted Y or or the single string suspension arm please visit my web page at
www.apricot.com/~bgruhn/turntable/magarms.html
Thanks
Bill
ost #15Hello Schröder tone arm fans,
I thought I had successfully posted this note last night but It appears something went wrong. If tonight's post is a duplicate (more or less) Mr Moderator please delete this one. Thank you.
Post #15 discusses my progress making a Schröder inspired tone arm and mentions an alternate inverted Y design I put together for test and experiment work. For some more information and photos of this version as well as photos of my DIY turntable using Corian for plinth, base and platter, and the WTA clone I am expecting to replace with a version of either the inverted Y or or the single string suspension arm please visit my web page at
www.apricot.com/~bgruhn/turntable/magarms.html
Thanks
Bill
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