Personally I am interested in the quality of the sound of the reproduced music. I am not interested in “grand designs”. Nevertheless, I am born with 2 right hands so after a while I mostly replace the last prototype for a more sophisticated one. And that’s why - at the moment - I cannot show photographs of the linear tonearm that’s gleaming in the shop-window (I have to make a new turntable too).
I am not the only one that has build this tonearm, someone else has build a prototype too (see photo above). His opinion about the quality of the sound: “Black silence between tracks; voice and instruments separate from each other; wonderful tight base (non-booming); sweet musicality from top to bottom, front to back and side to side”.
Moreover, the tonearm is impervious for the quality of the cartridge. It facilitates every cartridge optimal: from the Audio Technica MM AT-91 (25 euro) to the Ortofon Anna (5000 euro). I have tested all those different VTF’s in combination to the cartridge weights. The image below shows one of my own prototypes.
This tonearm functions not like all the other fixed pivot and linear tonearms. It is a total new principle to facilitate the cartridge (physics). Only the friction – pull – between the rotating record and the tip of the stylus of the cartridge is responsible for the movement of the tonearm from the outer side to the inner side of the record. Without servo mechanism or air bearing. The stability of this principle of “moving the pivot” is tested with 12 inch records of different duration: between 4 and 26 minutes. But besides of that, this tonearm is really simple to build and all the materials cost about 40 euro (inclusive 900 ml ice cream). The image below shows the composition of the tonearm.
The phono cartridge is not build yet. I have ordered some materials to make the first prototype (new principle). Because this cartridge is planned to function with this new type of tonearm I have incorporated the cartridge to this topic.
An externally hosted image should be here but it was not working when we last tested it.
I am not the only one that has build this tonearm, someone else has build a prototype too (see photo above). His opinion about the quality of the sound: “Black silence between tracks; voice and instruments separate from each other; wonderful tight base (non-booming); sweet musicality from top to bottom, front to back and side to side”.
Moreover, the tonearm is impervious for the quality of the cartridge. It facilitates every cartridge optimal: from the Audio Technica MM AT-91 (25 euro) to the Ortofon Anna (5000 euro). I have tested all those different VTF’s in combination to the cartridge weights. The image below shows one of my own prototypes.
An externally hosted image should be here but it was not working when we last tested it.
This tonearm functions not like all the other fixed pivot and linear tonearms. It is a total new principle to facilitate the cartridge (physics). Only the friction – pull – between the rotating record and the tip of the stylus of the cartridge is responsible for the movement of the tonearm from the outer side to the inner side of the record. Without servo mechanism or air bearing. The stability of this principle of “moving the pivot” is tested with 12 inch records of different duration: between 4 and 26 minutes. But besides of that, this tonearm is really simple to build and all the materials cost about 40 euro (inclusive 900 ml ice cream). The image below shows the composition of the tonearm.
An externally hosted image should be here but it was not working when we last tested it.
The phono cartridge is not build yet. I have ordered some materials to make the first prototype (new principle). Because this cartridge is planned to function with this new type of tonearm I have incorporated the cartridge to this topic.
interesting ! , do you mean a new principle different from moving magnet, moving coil, strain gauge... could you elaborate a little more.
It looks like the subject of this thread :
Late model Well-Tempered owners here? - Page 8 - Turntables and Tonearms Forum - Vinyl Engine
Late model Well-Tempered owners here? - Page 8 - Turntables and Tonearms Forum - Vinyl Engine
@Soyuz,
“New principle” is not restricted to the type of the transformer (mechanical vibrations into electric frequencies and amplitudes). I don’t think that one of those generators – electromagnetic, piezoelectric or by photodiode/-transistor – will outperform the others. It is more the way how we practice the whole process of transforming the mechanical recording into the electric signal.
And from that point of view the DIY cartridge is – like the linear tonearm – not a known principle. The image above shows the semi-realistic appliance. It is clear that one of the targets is to get 100% channel separation.
@Arch Stanton,
You are quite right. Unfortunately the forum of vinylengine has not much visitors that DIY by themselves. Repairing audio equipment is more their profession.
“New principle” is not restricted to the type of the transformer (mechanical vibrations into electric frequencies and amplitudes). I don’t think that one of those generators – electromagnetic, piezoelectric or by photodiode/-transistor – will outperform the others. It is more the way how we practice the whole process of transforming the mechanical recording into the electric signal.
An externally hosted image should be here but it was not working when we last tested it.
And from that point of view the DIY cartridge is – like the linear tonearm – not a known principle. The image above shows the semi-realistic appliance. It is clear that one of the targets is to get 100% channel separation.
@Arch Stanton,
You are quite right. Unfortunately the forum of vinylengine has not much visitors that DIY by themselves. Repairing audio equipment is more their profession.
Today I got the ordered neodymium magnets. The image below shows the ordered types (the background is P280 emary paper). Just the 3 smallest types available because I was afraid that the smallest – 1 x 1 mm – probably wouldn’t work well, despite of the specifications. And… replacing the topmost magnet – see the image of the cartridge in the post before – by a stronger one, will increase the push off between both magnets.
I have to say that I didn’t realize myself that small neodymium magnets are like insects: they jump up in the air if other neodymium magnets come nearby. So you have to use brass tweezers…
The weight of the smallest magnets – 1 x 1 mm – is 0,006 gram, just the weight of a stylus and cantilever together. Therefore, I liked to start the first experiment with these magnets. To buy a transparent tube with an inner diameter of 1,1 mm somewhere, isn’t easy (I couldn’t find one). So I made one myself.
The experiment is quite simple: 2 magnets with opposite pole into the tube and a weight of ½ the VTF of 1,5 gram on top of the uppermost magnet. To secure low friction I put some silicon oil into the tube. The image below shows the experiment.
The distance between the 2 small magnets appeared to be about 1,75 mm. A bit more than the distance between both magnets at the image of the cartridge. Doubling the magnetic power of the uppermost magnet – just by adding another magnet – increased the distance into 2 mm. Nevertheless, I prefer a symmetric structure.
Conclusion: when the vibrating bottommost magnet has enough “power” to create a suitable voltage in a DIY coil that surrounds the tube, it is time to think in a serious way about the fabrication of a simple prototype.
I have to say that I didn’t realize myself that small neodymium magnets are like insects: they jump up in the air if other neodymium magnets come nearby. So you have to use brass tweezers…
An externally hosted image should be here but it was not working when we last tested it.
The weight of the smallest magnets – 1 x 1 mm – is 0,006 gram, just the weight of a stylus and cantilever together. Therefore, I liked to start the first experiment with these magnets. To buy a transparent tube with an inner diameter of 1,1 mm somewhere, isn’t easy (I couldn’t find one). So I made one myself.
The experiment is quite simple: 2 magnets with opposite pole into the tube and a weight of ½ the VTF of 1,5 gram on top of the uppermost magnet. To secure low friction I put some silicon oil into the tube. The image below shows the experiment.
An externally hosted image should be here but it was not working when we last tested it.
The distance between the 2 small magnets appeared to be about 1,75 mm. A bit more than the distance between both magnets at the image of the cartridge. Doubling the magnetic power of the uppermost magnet – just by adding another magnet – increased the distance into 2 mm. Nevertheless, I prefer a symmetric structure.
Conclusion: when the vibrating bottommost magnet has enough “power” to create a suitable voltage in a DIY coil that surrounds the tube, it is time to think in a serious way about the fabrication of a simple prototype.
Hello Tom
I see you have 'picked up' (no pun intended) on Henk's design for a tonearm recently featured in the Vinyl Engine forum. I've been asking questions and gaining a good understanding as to how it works- and am just about ready to make a prototype-looks very interesting indeed.......
Chris
I see you have 'picked up' (no pun intended) on Henk's design for a tonearm recently featured in the Vinyl Engine forum. I've been asking questions and gaining a good understanding as to how it works- and am just about ready to make a prototype-looks very interesting indeed.......
Chris
Is it possible to DIY a “microscopic” cartridge?
Well, that isn’t so difficult. You only have to choose those solutions that are DIY’able. For example, I have silver wire of 0,008 mm thick. But I will not use this wire to make a coil with a lot of windings. That’s far too difficult without a stereo microscope. Nevertheless, when I use a neodymium magnet to “drive” the coil, I can reduce the windings and use silver wire of about 0,08 mm thick.
Moreover, with a bit puzzling it is possible to find simple solutions. See the image below; I have made pictures of the first experiment. The tube is made of transparent heat shrink tubing. I only had to look for a needle of about 1,05 – 1,1 mm thick. I rubbed the needle with silicon oil, stuck it into the heat shrink tubing and heated it. At the end in cold water and glued upon a piece of transparent plastic. When the glue was dry I removed the needle and got a straight tube with an inner diameter of 1,1 mm… Simple.
The image at the right hand shows the two 1 x 1 mm magnets without any weight upon, so their mutual distance is 5,42 mm. The image at the left hand includes a weight of 1 gram upon the uppermost magnet (it is a carbon tube). When I increase the weight to 1,25 gram, the mutual distance altered to nearly 1,63 mm (some high end cartridges have a VTF of 2 x 1,25 gram = 2,5 gram). With other words, those two small neodymium magnets can “operate” within the VTF bandwidth of common MM and MC cartridges.
When you think it over, you probably see a problem because the magnetic ricocheting force surely will damp the amplitude of the stylus. Will it?
The amplitudes arise from the rigid modulated groove. Therefore, the bottommost magnet will move according to the modulations of the groove. Just because the connection between the stylus and the bottommost magnet is a rigid one (again the image).
Thus, when there is no uppermost magnet the stylus will lose the rigid contact with the bottommost magnet. Therefore the uppermost magnet constantly pushes the bottommost magnet to the stylus (via the small carbon rod).
Now you can understand why this hypothetical cartridge is meant for the linear tonearm of this topic. The constant magnetic push from both cylinders will manage the tonearm far better along the horizontal bar than the suspension of a traditional MM and MC cartridge.
The first experiment was successful, so I ordered a long brass tube with a wall of 0,2 mm thick. To get the coil as close as possible around the magnet. Thus I have to wait a week.
Well, that isn’t so difficult. You only have to choose those solutions that are DIY’able. For example, I have silver wire of 0,008 mm thick. But I will not use this wire to make a coil with a lot of windings. That’s far too difficult without a stereo microscope. Nevertheless, when I use a neodymium magnet to “drive” the coil, I can reduce the windings and use silver wire of about 0,08 mm thick.
Moreover, with a bit puzzling it is possible to find simple solutions. See the image below; I have made pictures of the first experiment. The tube is made of transparent heat shrink tubing. I only had to look for a needle of about 1,05 – 1,1 mm thick. I rubbed the needle with silicon oil, stuck it into the heat shrink tubing and heated it. At the end in cold water and glued upon a piece of transparent plastic. When the glue was dry I removed the needle and got a straight tube with an inner diameter of 1,1 mm… Simple.
An externally hosted image should be here but it was not working when we last tested it.
The image at the right hand shows the two 1 x 1 mm magnets without any weight upon, so their mutual distance is 5,42 mm. The image at the left hand includes a weight of 1 gram upon the uppermost magnet (it is a carbon tube). When I increase the weight to 1,25 gram, the mutual distance altered to nearly 1,63 mm (some high end cartridges have a VTF of 2 x 1,25 gram = 2,5 gram). With other words, those two small neodymium magnets can “operate” within the VTF bandwidth of common MM and MC cartridges.
When you think it over, you probably see a problem because the magnetic ricocheting force surely will damp the amplitude of the stylus. Will it?
The amplitudes arise from the rigid modulated groove. Therefore, the bottommost magnet will move according to the modulations of the groove. Just because the connection between the stylus and the bottommost magnet is a rigid one (again the image).
An externally hosted image should be here but it was not working when we last tested it.
Thus, when there is no uppermost magnet the stylus will lose the rigid contact with the bottommost magnet. Therefore the uppermost magnet constantly pushes the bottommost magnet to the stylus (via the small carbon rod).
Now you can understand why this hypothetical cartridge is meant for the linear tonearm of this topic. The constant magnetic push from both cylinders will manage the tonearm far better along the horizontal bar than the suspension of a traditional MM and MC cartridge.
The first experiment was successful, so I ordered a long brass tube with a wall of 0,2 mm thick. To get the coil as close as possible around the magnet. Thus I have to wait a week.
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@SY,
Discussing the wear of the groove is discussing the unbalance of the wear. Because the 2 parameters – the VTF and the speed of the record – will be unchanged. So the question is: will the magnetic push against both sides of the stylus cause an new unbalance in the wear of the “top and bottom” of the local overhang of both walls of the groove (the amplitude of the modulation).
When we are concerned about the wear of the groove by this hypothetical cartridge, we compare the wear of this magnetic principle “on top” of the stylus with the wear by a good MC cartridge. The traditional suspension of MC cartridges is at the end of the cantilever. That means a low physical bandwidth – in relation to the diverges of the stylus – and an uncontrolled (= passive) damping of the movements of the cantilever. Moreover, because the suspension is at the end of the cantilever, it acts more like a stiff fishing rod in the hands of an angler when he tries to get the fish to the bank.
From that point of view I agree with you that there will be an alteration in the wear of the groove. My expectation is a more uniform wear of the modulation. Nevertheless, because the cantilever is the rope between stylus and cartridge, lengthen the cantilever and lowering the VTF will have a positive effect on the wear of the modulation (but the main purpose is the quality of the reproduced sound).
Personally I am a bit concerned about the mutual influence of the 4 magnets on the quality of the generated electric signals. The distance between the 2 bottom most magnets is about 3 – 5 mm (I don’t want to much support of the carbon rod). The angle between both magnets (the “drivers”) is 90 degrees – the best position to eliminate the mutual influence – but these magnets are really strong. Maybe I have to read about the shielding of magnetic forces before I try to build a prototype (but first I have to do some experiments with one cylinder and a coil).
There is not so much freedom in this design. I can increase the internal diameter of the cylinders to 1,5 mm (using the 1,5 x 0,5 mm magnets) and glue the carbon rod to the the magnet so it cannot topple. The consequence is an increase of the dimensions of the prism and the carbon rod. The strength of these magnets is about 115% in comparison to the 1 x 1 mm magnets. But more important: the nearly spherical shape of the magnetic field. Perhaps this will "smooth" the vibrating magnetic force lines a bit by their mutual influence.
Discussing the wear of the groove is discussing the unbalance of the wear. Because the 2 parameters – the VTF and the speed of the record – will be unchanged. So the question is: will the magnetic push against both sides of the stylus cause an new unbalance in the wear of the “top and bottom” of the local overhang of both walls of the groove (the amplitude of the modulation).
When we are concerned about the wear of the groove by this hypothetical cartridge, we compare the wear of this magnetic principle “on top” of the stylus with the wear by a good MC cartridge. The traditional suspension of MC cartridges is at the end of the cantilever. That means a low physical bandwidth – in relation to the diverges of the stylus – and an uncontrolled (= passive) damping of the movements of the cantilever. Moreover, because the suspension is at the end of the cantilever, it acts more like a stiff fishing rod in the hands of an angler when he tries to get the fish to the bank.
From that point of view I agree with you that there will be an alteration in the wear of the groove. My expectation is a more uniform wear of the modulation. Nevertheless, because the cantilever is the rope between stylus and cartridge, lengthen the cantilever and lowering the VTF will have a positive effect on the wear of the modulation (but the main purpose is the quality of the reproduced sound).
Personally I am a bit concerned about the mutual influence of the 4 magnets on the quality of the generated electric signals. The distance between the 2 bottom most magnets is about 3 – 5 mm (I don’t want to much support of the carbon rod). The angle between both magnets (the “drivers”) is 90 degrees – the best position to eliminate the mutual influence – but these magnets are really strong. Maybe I have to read about the shielding of magnetic forces before I try to build a prototype (but first I have to do some experiments with one cylinder and a coil).
There is not so much freedom in this design. I can increase the internal diameter of the cylinders to 1,5 mm (using the 1,5 x 0,5 mm magnets) and glue the carbon rod to the the magnet so it cannot topple. The consequence is an increase of the dimensions of the prism and the carbon rod. The strength of these magnets is about 115% in comparison to the 1 x 1 mm magnets. But more important: the nearly spherical shape of the magnetic field. Perhaps this will "smooth" the vibrating magnetic force lines a bit by their mutual influence.
Oh sorry... now I understand what you mean!
The stylus and cantilever act like a swiveling wheel. There is a force - caused by the pull of the record - that pushes the stylus to the neutral position. The more amplitude, the stronger this force. The length of the cantilever has an 1 tot 1 relation to the strength of this force (2 x as long = 1/2 the force).
The strength of the repulsive magnetic force will increase with the amplitude of the groove (square root of the distance). Will this result in the need to increase the VTF because this proportional increase of the inward force will cause the stylus to loose the right contact with the groove? (the foundation of your question).
I will think about it, because in every position the stylus is in equilibrium with the groove. The focus on one facet will probably result in a wrong answer.
The stylus and cantilever act like a swiveling wheel. There is a force - caused by the pull of the record - that pushes the stylus to the neutral position. The more amplitude, the stronger this force. The length of the cantilever has an 1 tot 1 relation to the strength of this force (2 x as long = 1/2 the force).
The strength of the repulsive magnetic force will increase with the amplitude of the groove (square root of the distance). Will this result in the need to increase the VTF because this proportional increase of the inward force will cause the stylus to loose the right contact with the groove? (the foundation of your question).
I will think about it, because in every position the stylus is in equilibrium with the groove. The focus on one facet will probably result in a wrong answer.
@SY,
When I make some simple calculations, the repulsive force of the magnets will increase the correcting force of the pull at the end of the cantilever by 10% when the amplitude of the stylus is 25 micron (in the horizontal plane). Nevertheless, this calculation is done by the assumption that only one cylinder/channel is in motion and the VTF is divided in two equal portions.
When the friction increases by the amplitude of the groove, the stylus mostly will drive the magnets in both cylinders (both channels produce a sound). So even when the tip of the stylus is at a position at the right or left side of the centerline of the groove, both cylinders will be involved (see http://phia.home.xs4all.nl/tsu/ST.avi) .
The repulsive force of one cylinder will push the stylus to the outer wall of the groove and the repulsive force of the other cylinder will push the stylus to the inner wall of the groove. Nevertheless, there must be a equilibrium between both repulsive forces at every single moment because the mass of the VTF cannot increase or decrease.
When the stylus leaves the neutral position, the dividing of the VTF for each cylinder will change because the centre of the mass will move aside. So both repulsive forces will change too. Will it be in a positive way – less unbalance - or in a negative way – more unbalance?
At the side of amplitude the VTF upon the cylinder will decrease, so the alteration of the centre of the mass will be positive for the balance of the forces at both sides of the groove.
Well, I hope that reality will confirm this argumentation...
When I make some simple calculations, the repulsive force of the magnets will increase the correcting force of the pull at the end of the cantilever by 10% when the amplitude of the stylus is 25 micron (in the horizontal plane). Nevertheless, this calculation is done by the assumption that only one cylinder/channel is in motion and the VTF is divided in two equal portions.
When the friction increases by the amplitude of the groove, the stylus mostly will drive the magnets in both cylinders (both channels produce a sound). So even when the tip of the stylus is at a position at the right or left side of the centerline of the groove, both cylinders will be involved (see http://phia.home.xs4all.nl/tsu/ST.avi) .
The repulsive force of one cylinder will push the stylus to the outer wall of the groove and the repulsive force of the other cylinder will push the stylus to the inner wall of the groove. Nevertheless, there must be a equilibrium between both repulsive forces at every single moment because the mass of the VTF cannot increase or decrease.
When the stylus leaves the neutral position, the dividing of the VTF for each cylinder will change because the centre of the mass will move aside. So both repulsive forces will change too. Will it be in a positive way – less unbalance - or in a negative way – more unbalance?
At the side of amplitude the VTF upon the cylinder will decrease, so the alteration of the centre of the mass will be positive for the balance of the forces at both sides of the groove.
Well, I hope that reality will confirm this argumentation...
@Arch Stanton,
Neodymium magnets are brittle. The nice gleaming surface is nickel. Therefore it is not wise to use the magnet as a kind of piston, moving against the wall of the cylinder. That’s why I better can use the 0,5 x 1,5 mm magnets and use the “carbon rod” as the mechanical slider of the magnet (I will replace the carbon rod by a Nylon-66 one, because Nylon-66 acts like a greased bar). There exist sintered brass too that is porous and can be filled with lubricating oil. Maybe I can find some small tubes.
I have ordered brass tubes and some are chromed at the surface. Unfortunately they all have an inner diameter of 1 or 1,1 mm… Therefore I will order some other tubes.
There are materials that are very nice to practice as a cylinder. Like Nylon-66. Unfortunately the smallest internal diameter of the tubes I could find are about 6 mm and the thickness of the wall is 4 mm or more. Therefore I will use brass to test the properties of the coil (output voltage, etc.). Later on I will worry myself over the best materials.
Neodymium magnets are brittle. The nice gleaming surface is nickel. Therefore it is not wise to use the magnet as a kind of piston, moving against the wall of the cylinder. That’s why I better can use the 0,5 x 1,5 mm magnets and use the “carbon rod” as the mechanical slider of the magnet (I will replace the carbon rod by a Nylon-66 one, because Nylon-66 acts like a greased bar). There exist sintered brass too that is porous and can be filled with lubricating oil. Maybe I can find some small tubes.
I have ordered brass tubes and some are chromed at the surface. Unfortunately they all have an inner diameter of 1 or 1,1 mm… Therefore I will order some other tubes.
There are materials that are very nice to practice as a cylinder. Like Nylon-66. Unfortunately the smallest internal diameter of the tubes I could find are about 6 mm and the thickness of the wall is 4 mm or more. Therefore I will use brass to test the properties of the coil (output voltage, etc.). Later on I will worry myself over the best materials.
Magnetic force is very non-linear two magnets repelling each other in a plastic tube do not behave like a mass and spring.
@scott wurcer,
Sorry I used the wrong words (and too few).
The magnetic force will decrease with the quadrate of the distance, seen from the center of the force (I had vague a point within the field in mind). That’s what SY concerned: one cylinder is “compressed” by the amplitude of the stylus, so the magnetic force increases far more than the magnetic force decreases when the magnet moves the same distance in the other direction. So there seems to be no “neutral” damping of the stylus.
The length of the cantilever and the amplitude of the stylus determines the angle of the cantilever in relation to the centerline of the cartridge. That’s the force of the pull by the record at the tip of the stylus and this force has no relation to the magnetic force.
Sorry I used the wrong words (and too few).
The magnetic force will decrease with the quadrate of the distance, seen from the center of the force (I had vague a point within the field in mind). That’s what SY concerned: one cylinder is “compressed” by the amplitude of the stylus, so the magnetic force increases far more than the magnetic force decreases when the magnet moves the same distance in the other direction. So there seems to be no “neutral” damping of the stylus.
The length of the cantilever and the amplitude of the stylus determines the angle of the cantilever in relation to the centerline of the cartridge. That’s the force of the pull by the record at the tip of the stylus and this force has no relation to the magnetic force.
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