ARBITRARY, you set up your tonearm arbitrary????Whatever you want, everything is arbitrary.
Regards zeoN_Rider
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First determine your arm length, then find alignment guides that are posted all over the web. See which cartridge you want to use and get the spec. Take all the numbers and lay them out with a CAD drawing program and build your arm with those numbers.
There is no "set" distance" other than what you determine for your own individual choices. Unles... you are directly copying an already made arm 1 : 1.
JD
There is no "set" distance" other than what you determine for your own individual choices. Unles... you are directly copying an already made arm 1 : 1.
JD
Frank would not look too keenly on that nor on anyone discovered to do your work and homework for you. . He has VERY GENEROUSLY offered, and freely given his help here in this thread on this forum, with the understanding that this is strictly D.I.Y. not do it for others. Asking for someone to do it for you is a slap in his face and the rest of us in this thread.
Peeps here will more than happily give you all the help, advise, and understanding for you to have the ultimate satisfaction of building a "Shcroederesque" tonearm with your own two hands and an learned understanding of the priciples involved.
If someone other than Frank builds you a tonearm, he may very well be putting Franks children through University, and probably will end his contribution here. I would not blame him one bit if he even asked the moderators of this forum to pull all of his posts in this thread. That would surely be an awful circumstance if he did as we would all bear punishment from the action of a couple of individuals (you and your cohort).
JD
Peeps here will more than happily give you all the help, advise, and understanding for you to have the ultimate satisfaction of building a "Shcroederesque" tonearm with your own two hands and an learned understanding of the priciples involved.
If someone other than Frank builds you a tonearm, he may very well be putting Franks children through University, and probably will end his contribution here. I would not blame him one bit if he even asked the moderators of this forum to pull all of his posts in this thread. That would surely be an awful circumstance if he did as we would all bear punishment from the action of a couple of individuals (you and your cohort).
JD
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Hello
If you are willing to pay someone to build you a Frank Schröder Tonearm, why not Frank Schröder himself? If someone other than Frank would build it, it would certainly cost more, assuming the same build quality. The reason for the higher cost would be the fact that the unknown maker would have to buy his supplies in single quantities and at retail whereas Frank buys in larger quantities and at wholesale. Also, since the Arm is patented, there would also be a problem with patent infringement. So, buying one from Frank would the wiser choice. Just think of the pride of ownership.
Sincerely,
Ralf
If you are willing to pay someone to build you a Frank Schröder Tonearm, why not Frank Schröder himself? If someone other than Frank would build it, it would certainly cost more, assuming the same build quality. The reason for the higher cost would be the fact that the unknown maker would have to buy his supplies in single quantities and at retail whereas Frank buys in larger quantities and at wholesale. Also, since the Arm is patented, there would also be a problem with patent infringement. So, buying one from Frank would the wiser choice. Just think of the pride of ownership.
Sincerely,
Ralf
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Hi Guys,
Thanks for the support! And, as anyone of those who built a nicely executed version of my design all by himself can attest, it more likely than not cost him quite a lot of time, spent on familiarizing oneself with the principle AND executing it. If those DIYers had paid themselves what they get paid per hour in their profession, the arm certainly didn't come cheap. But hopefully, all of you got an excellent sounding arm and something often more valuable than the pride of ownership: that of achievement.
@murphythecat8: Since you don't have the time to build your own Schröder arm "clone", would it be correct to assume that you are so busy making money that you could actually afford an original, rather than getting a DIY forum member in trouble for patent infringement? Just wondering....
Cheers,
Frank
Thanks for the support! And, as anyone of those who built a nicely executed version of my design all by himself can attest, it more likely than not cost him quite a lot of time, spent on familiarizing oneself with the principle AND executing it. If those DIYers had paid themselves what they get paid per hour in their profession, the arm certainly didn't come cheap. But hopefully, all of you got an excellent sounding arm and something often more valuable than the pride of ownership: that of achievement.
@murphythecat8: Since you don't have the time to build your own Schröder arm "clone", would it be correct to assume that you are so busy making money that you could actually afford an original, rather than getting a DIY forum member in trouble for patent infringement? Just wondering....
Cheers,
Frank
What an amazing thread.
I was contemplating a DIY conventional unipivot, after reading this I need to have a major re-think. Hats off to Frank, what a simple elegant concept. Like most things the details are what it is all about, but the principle is so appealing.
One thing (only one, I wish) the upper end of the line is attched to an adjustable 2 part knob. The centre part adjusts up and down to set magnet gap and the outer part can be rotated, taking the inner part with it, to create twist in the line, as a form of anti skate - got that right I think.
How are you guys connecting the line to the centre part?
It has to be strong enough to withstand the magnet pull and also can not rotate or the line could not be twisted. A simple hole and a knot in the line will not do, or will it? How much twist is their.......confused. Thought about grub screw in the side of the centre part etc, the pictures do not show any obvious or bulky contraptions so it must be somthing simple?
Can not start drawing somthing up till I get this sorted out, in principle.
Just thought, what stops the lower end rotating.....Doohhh!
Ken
I was contemplating a DIY conventional unipivot, after reading this I need to have a major re-think. Hats off to Frank, what a simple elegant concept. Like most things the details are what it is all about, but the principle is so appealing.
One thing (only one, I wish) the upper end of the line is attched to an adjustable 2 part knob. The centre part adjusts up and down to set magnet gap and the outer part can be rotated, taking the inner part with it, to create twist in the line, as a form of anti skate - got that right I think.
How are you guys connecting the line to the centre part?
It has to be strong enough to withstand the magnet pull and also can not rotate or the line could not be twisted. A simple hole and a knot in the line will not do, or will it? How much twist is their.......confused. Thought about grub screw in the side of the centre part etc, the pictures do not show any obvious or bulky contraptions so it must be somthing simple?
Can not start drawing somthing up till I get this sorted out, in principle.
Just thought, what stops the lower end rotating.....Doohhh!
Ken
[0000]I was wondering if anyone would be willing to build me one of those arms?
Please pm me, and well fix a price[/QUOTE]
If you are unable to build your own arm you must purchase one from Frank, doing otherwise is a violation of the terms by which this thread exists.
Please pm me, and well fix a price[/QUOTE]
If you are unable to build your own arm you must purchase one from Frank, doing otherwise is a violation of the terms by which this thread exists.
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A double or triple knot should do the trick. The knot(s) should be larger than the diameter of the hole and it (so far on mine for over a year now) should not compress / un-knot / pull through.
I used a drop of super glue on the knot once it's in place in the bottom of the grub screw. It wont pull through or rotate independantly of the grub screw. Tried first on a test part just to be sure. Just be sure that the knot sits shallow enough inside the bottom of the hex hole in the grub screw so you can use the allen key.
What stops the bottom? On mine another double knot inside a dimpled plate (with a central hole) in the arm body, above the magnet, Just a drop of super-glue keeps the string in place on the plate. The dimpled plate/disc I use is a press fit into the arm body and it will not rotate in the cavity.
JD
I used a drop of super glue on the knot once it's in place in the bottom of the grub screw. It wont pull through or rotate independantly of the grub screw. Tried first on a test part just to be sure. Just be sure that the knot sits shallow enough inside the bottom of the hex hole in the grub screw so you can use the allen key.
What stops the bottom? On mine another double knot inside a dimpled plate (with a central hole) in the arm body, above the magnet, Just a drop of super-glue keeps the string in place on the plate. The dimpled plate/disc I use is a press fit into the arm body and it will not rotate in the cavity.
JD
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Ugh, don't I know it. Building this arm has been anything but easy, but I'm nearing the end of the process. Really looking forward to a listen! You've got quite an imagination to have dreamt this concept up Frank. Thanks for the contribution!
JD - Thanks for confirming how you hold the string.
I might try an alternative glue as super glue is a bit perminant.
I use super glue on the braided line knots when I am fishing, stops them undoing nicely.
For the bottom end I am going to use a csk magnet in the arm, this is designed to take a fixing screw head. I am thinking of using a plastic bead (fishing tackle) and a knot in the thread, super glued to the bead. The bead will centre the line in the csk and through hole. I may need to stick the bead to the magnet to stop rotation. It will give a nice low pivot point (roughly mid depth in the magnet).
The csk magnet I am looking at is dia 10mm x 5mm thick with a 3.2mm through hole that has a csk.
I can only find N42 and was worried about the strength of this type/size. When I compared its pull off strength and Gauss figures, to a standard N42 Dia 10mm x 5mm disc magnet, there wasn't much difference. In fact both figures were higher than on a 4mm thick Dia 10mm N42. So I guess there mustn't be a significant loss of mass and it would be ok to use. Certainly avoids drilling the magnet. I could allways use a thicker or higher N number for the magnet in the base to help. Or are magnets of a large difference in pulling power not good to work together? (not my area of expertise).
Has anyone tried a csk magnet? Opinions good/bad please?
I might try an alternative glue as super glue is a bit perminant.
I use super glue on the braided line knots when I am fishing, stops them undoing nicely.
For the bottom end I am going to use a csk magnet in the arm, this is designed to take a fixing screw head. I am thinking of using a plastic bead (fishing tackle) and a knot in the thread, super glued to the bead. The bead will centre the line in the csk and through hole. I may need to stick the bead to the magnet to stop rotation. It will give a nice low pivot point (roughly mid depth in the magnet).
The csk magnet I am looking at is dia 10mm x 5mm thick with a 3.2mm through hole that has a csk.
I can only find N42 and was worried about the strength of this type/size. When I compared its pull off strength and Gauss figures, to a standard N42 Dia 10mm x 5mm disc magnet, there wasn't much difference. In fact both figures were higher than on a 4mm thick Dia 10mm N42. So I guess there mustn't be a significant loss of mass and it would be ok to use. Certainly avoids drilling the magnet. I could allways use a thicker or higher N number for the magnet in the base to help. Or are magnets of a large difference in pulling power not good to work together? (not my area of expertise).
Has anyone tried a csk magnet? Opinions good/bad please?
Headshell design
Berlinta - Hope you are around.
I am pulling in design information and supplier leads for raw materials etc prior to starting my own diy arm based on your fabulous concept.
I have a question relating to your headshell design, which may have an obvious answer I have not considered, but please bear with me on this as I am not great with the phisics in arm design and I am trying to deal with the fundamentals.
I notce that some designs (unipivot) recomend the stylus tip should line up with the centre line of the arm and that the bearing point should be at record height, putting the stylus at the centre of bearing rotation. As I understand it, this reduces movement of the stylus in the groove down to rotation rather than a distance traveled accross the record and requires less work from the cantlever compliance to deal with.
I would make a simple analogy to help describe (for everyone) what I mean.
1. If you had a design with the bearing centre of rotation exactly in the middle of the arm and you were to look on the end of the (straight) arm at the cartridge.
2. You compare this with the hand on a clock face with the centre of the clock being the centre of the tonearm.
Ok so if the stylus is at the centre of rotation, this is like being at the centre of the clock pointer shaft. Any tendancy for the arm to rotate at the pivot, which can be a problem for most unipivots, does not cause movement of the stylus, but it will change its angle in the groove.
(A). If the stylus is below the horizontal bearing axis but still ligned up with the vertical axis, this is equivilant to the stylus bieng on the end of the clock hand at 6 o'clock position. Any rotation of the tonearm will rock the pionter between 5 and 7 say. This gives a lot of horizontal movement (accross the grooves) with very little vertical movement.
(B). If the stylus lignes up with the horizontal axis but is inboard of the vertical axis, this is like the pointer being at 9 o'clock. Any rotation of the arm, say between 8 and 10 o'clock, will induce larger vertical movement for the cartridge compliance to deal with, but have very little horizontal movement accross the grooves.
The stylus (pointer) could reside at any position between the two examples with movement results equivilant to the appropriate clock positions. The greater the distance the stylus is from the axis the longer the pointer on the clock = greater distance moved for any given amount of rotation.
On your headshell the stylus appears (I'm Guessing here) to be similar to sinario (B). Approx. lighning up with the virtual horizontal axis but being inboard of the vertical axis.
Do you think it would be a good idea to try and align the stylus with the vertical axis, that is, line it up with the arm centre line.?
You can not do this with your current design. As I see it, the challange is to be able to adjust the effective length to the correct distance while keeping the correct offset angle and not moving the stylus tip off the arm centre line. Difficult to achieve all three, but if you can't then protractor alignment will be out and a compramise will have to be made.
What is your take on this?
Sorry for dumming it down, I wanted to make it easilly understood by the whole audiance, including myself.
Berlinta - Hope you are around.
I am pulling in design information and supplier leads for raw materials etc prior to starting my own diy arm based on your fabulous concept.
I have a question relating to your headshell design, which may have an obvious answer I have not considered, but please bear with me on this as I am not great with the phisics in arm design and I am trying to deal with the fundamentals.
I notce that some designs (unipivot) recomend the stylus tip should line up with the centre line of the arm and that the bearing point should be at record height, putting the stylus at the centre of bearing rotation. As I understand it, this reduces movement of the stylus in the groove down to rotation rather than a distance traveled accross the record and requires less work from the cantlever compliance to deal with.
I would make a simple analogy to help describe (for everyone) what I mean.
1. If you had a design with the bearing centre of rotation exactly in the middle of the arm and you were to look on the end of the (straight) arm at the cartridge.
2. You compare this with the hand on a clock face with the centre of the clock being the centre of the tonearm.
Ok so if the stylus is at the centre of rotation, this is like being at the centre of the clock pointer shaft. Any tendancy for the arm to rotate at the pivot, which can be a problem for most unipivots, does not cause movement of the stylus, but it will change its angle in the groove.
(A). If the stylus is below the horizontal bearing axis but still ligned up with the vertical axis, this is equivilant to the stylus bieng on the end of the clock hand at 6 o'clock position. Any rotation of the tonearm will rock the pionter between 5 and 7 say. This gives a lot of horizontal movement (accross the grooves) with very little vertical movement.
(B). If the stylus lignes up with the horizontal axis but is inboard of the vertical axis, this is like the pointer being at 9 o'clock. Any rotation of the arm, say between 8 and 10 o'clock, will induce larger vertical movement for the cartridge compliance to deal with, but have very little horizontal movement accross the grooves.
The stylus (pointer) could reside at any position between the two examples with movement results equivilant to the appropriate clock positions. The greater the distance the stylus is from the axis the longer the pointer on the clock = greater distance moved for any given amount of rotation.
On your headshell the stylus appears (I'm Guessing here) to be similar to sinario (B). Approx. lighning up with the virtual horizontal axis but being inboard of the vertical axis.
Do you think it would be a good idea to try and align the stylus with the vertical axis, that is, line it up with the arm centre line.?
You can not do this with your current design. As I see it, the challange is to be able to adjust the effective length to the correct distance while keeping the correct offset angle and not moving the stylus tip off the arm centre line. Difficult to achieve all three, but if you can't then protractor alignment will be out and a compramise will have to be made.
What is your take on this?
Sorry for dumming it down, I wanted to make it easilly understood by the whole audiance, including myself.
Hello Qwin,
Just a few remarks, hopefully containg some answers to the questions you asked.
Using ring magnets is o.k. Different magnet materials(SmCo and NdFeB) or strengths(say, mixing N42 and N50) have no consequence other than influencing damping/resistance to displacement for a given distance between the magnets.
Locating the thread attachment point halfway between top and bottom surface of the ring magnet will result in an unstable bearing(you'll see...)
Securing a knot with super glue is o.k. as long as you don't saturate the thread with said glue. It will "solidify" and break after a short period of time. So: EASY on the super glue!
I've built arms with the cartridge tip "in line" with the armwand center, overhang to be adjusted by changing the spindle to pivot distance, but the headshell layout is less critical with this arm(and some Unipivots) than with arms that rely on even mass distribution on their vertical bearings. The cartridge tip can't "tell" what the arms mass distribution makeup is as long as the arm doesn't move rapidly. The bearing(thread) "sees" the same load, no matter what rotational position the armwand is assuming at any given moment(within the working environment that is the record player).
Generally your analogy is correct, in reality the offset angle for conventional pivoted arms dictates a condition between A and B.
Keeping the vertical pivot point as close to the record surface as possible is of greater importance(imho), any deviation has a more noticable effect(with warped records).
So, in essence, you can build the arm so that your cartridge tip is visually "in line" with the vertical axis, but that buys you little other than a counterweight hanging perfectly straight down for an ideal(azimuth required to be perfectly perpendicular to the record) cartridge, - or so you'd think. Now it's the uneven mass distribution due to the cartridge body "extending" to the right side(as seen head on) that'll require the (excentric)counterweight to be rotated slightly. Can't eat your cake and have it too...
Good luck with your project!
Frank
Just a few remarks, hopefully containg some answers to the questions you asked.
Using ring magnets is o.k. Different magnet materials(SmCo and NdFeB) or strengths(say, mixing N42 and N50) have no consequence other than influencing damping/resistance to displacement for a given distance between the magnets.
Locating the thread attachment point halfway between top and bottom surface of the ring magnet will result in an unstable bearing(you'll see...)
Securing a knot with super glue is o.k. as long as you don't saturate the thread with said glue. It will "solidify" and break after a short period of time. So: EASY on the super glue!
I've built arms with the cartridge tip "in line" with the armwand center, overhang to be adjusted by changing the spindle to pivot distance, but the headshell layout is less critical with this arm(and some Unipivots) than with arms that rely on even mass distribution on their vertical bearings. The cartridge tip can't "tell" what the arms mass distribution makeup is as long as the arm doesn't move rapidly. The bearing(thread) "sees" the same load, no matter what rotational position the armwand is assuming at any given moment(within the working environment that is the record player).
Generally your analogy is correct, in reality the offset angle for conventional pivoted arms dictates a condition between A and B.
Keeping the vertical pivot point as close to the record surface as possible is of greater importance(imho), any deviation has a more noticable effect(with warped records).
So, in essence, you can build the arm so that your cartridge tip is visually "in line" with the vertical axis, but that buys you little other than a counterweight hanging perfectly straight down for an ideal(azimuth required to be perfectly perpendicular to the record) cartridge, - or so you'd think. Now it's the uneven mass distribution due to the cartridge body "extending" to the right side(as seen head on) that'll require the (excentric)counterweight to be rotated slightly. Can't eat your cake and have it too...
Good luck with your project!
Frank
Hello Frank,
Thanks for the explanations and quick response.
I had wondered weather uneaven distribution of cartridge weight would figure in things thanks for the pointer.
If putting the pivot point mid way through the magnet is unstable, where is the best place for it? I am thinking, as close to the upper surface of the magnet as possible would that be correct? It is probably covered elseware in the thread, just can't spot it.
Thanks again
Ken
Thanks for the explanations and quick response.
I had wondered weather uneaven distribution of cartridge weight would figure in things thanks for the pointer.
If putting the pivot point mid way through the magnet is unstable, where is the best place for it? I am thinking, as close to the upper surface of the magnet as possible would that be correct? It is probably covered elseware in the thread, just can't spot it.
Thanks again
Ken