in this case shielding will be unuseful, will be attracted as the bearings. Plastic, or jewels as adviced, no other choice.
Anyway the design is always much more interesting than bearings. Keep us informed, Walter.
carlo
Anyway the design is always much more interesting than bearings. Keep us informed, Walter.
carlo
Carlo,
If the races are not perfectly round, any high point is attracted to the magnet and the bearing sticks. I could see this happening to the bearings I tested even with the magnet approx. 30 mm distant.
I agree with you that the design, not the bearings, is the interesting part and look forward to seeing walterwalter's PLT.
If the races are not perfectly round, any high point is attracted to the magnet and the bearing sticks. I could see this happening to the bearings I tested even with the magnet approx. 30 mm distant.
I agree with you that the design, not the bearings, is the interesting part and look forward to seeing walterwalter's PLT.
I think we are on the same wavelength. I have something in mind that might work.
When I have time and make a drawing, I will post it here. Keep digging!
Great, this thread is turning back to life, maybe it's the only one that can explore really new design concepts, instead of bearings and so on.
But I would like to make an appeal to everyone: tell us about your ideas, your projects, your successes and failures, do not wait until you have made the best arm in the world. It easier to learn from a boo than from an applause. Us and you.
TAs I have made in the last 2 years - good or bad - are born more from criticism than from the original idea, avoiding unseen mistakes, adding the experience of people with so much more knowledge than me.
Txs - carlo
But I would like to make an appeal to everyone: tell us about your ideas, your projects, your successes and failures, do not wait until you have made the best arm in the world. It easier to learn from a boo than from an applause. Us and you.
TAs I have made in the last 2 years - good or bad - are born more from criticism than from the original idea, avoiding unseen mistakes, adding the experience of people with so much more knowledge than me.
Txs - carlo
pivoting headshell
We might question the idea of pivoting headshell and having a bearing right above the cartridge but nobody is stopping new ideas and new designs. In an audiophile social media group, someone posted a picture of a modified Schroeder arm with a rotating headshell guided by magnets! Below are couple pictures and comment by the owner. There seems to be an extra black plate between the swiveling mount and cartridge and I wonder if that's for blocking magnetic field. Perhaps Frank can enlighten us on this one.
Also, check out this VIDEO at the 1:50 mark.
Another picture that shows the magnet on the rotating plate.
We might question the idea of pivoting headshell and having a bearing right above the cartridge but nobody is stopping new ideas and new designs. In an audiophile social media group, someone posted a picture of a modified Schroeder arm with a rotating headshell guided by magnets! Below are couple pictures and comment by the owner. There seems to be an extra black plate between the swiveling mount and cartridge and I wonder if that's for blocking magnetic field. Perhaps Frank can enlighten us on this one.
Also, check out this VIDEO at the 1:50 mark.
My Schroder CB and BA magnetic take the rotating or swing headshell to its ultimate realization! A tiny specific gauss magnet is placed in the arm wand above the headshell plate. The opposing equal gauss magnet is placed under it in the headshell plate. Now the headshell by means of a oil less super bushing can move minutely within the confines of the magnetic attraction- GENIUS FRANK SCHRODER! My favorite arm ever!
Another picture that shows the magnet on the rotating plate.
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Good evening!
I've built this arm(years ago) and several others like it(CB and BA types) to provide a tuneable antiresonator for the lateral plane, allowing for an eddy current damped (near-) cancellation of the lateral arm-cartridge resonance. Since essentially all low frequency information on vinyl is summed to mono below ~100Hz, one does not have to worry about low frequency energy at levels that could saturate an MC stepup(unlikely, I know...), but intermodulation distorsion too is considerably lower. No "flopping" bass reflex speaker cones either...
Bass "tightness"(lack of overhang) does improve...
This arrangement stemmed from my PLT built like Micha Huber's Thales(waaaay back in this thread), but with a thread/weight to provide alignment/antiskating. Now, unlike Micha's arm, which connects the alignment rod laterally rigidly, the thread allowed the rotating headshell plate to, well, rotate a bit, so that a lateral impulse would displace the cartridge(mounting plate), but not the stylus(which sits right underneath the vertical mounting plate bearing). So when the arm is exited laterally, no low frequency signal is generated. But it does go out of (offset angle-)alignment ever so slightly for a brief moment.
None of the above has anything to to with reducing the tracing error to zero(sorry) 🙂
Have a great weekend!
Frank
I've built this arm(years ago) and several others like it(CB and BA types) to provide a tuneable antiresonator for the lateral plane, allowing for an eddy current damped (near-) cancellation of the lateral arm-cartridge resonance. Since essentially all low frequency information on vinyl is summed to mono below ~100Hz, one does not have to worry about low frequency energy at levels that could saturate an MC stepup(unlikely, I know...), but intermodulation distorsion too is considerably lower. No "flopping" bass reflex speaker cones either...
Bass "tightness"(lack of overhang) does improve...
This arrangement stemmed from my PLT built like Micha Huber's Thales(waaaay back in this thread), but with a thread/weight to provide alignment/antiskating. Now, unlike Micha's arm, which connects the alignment rod laterally rigidly, the thread allowed the rotating headshell plate to, well, rotate a bit, so that a lateral impulse would displace the cartridge(mounting plate), but not the stylus(which sits right underneath the vertical mounting plate bearing). So when the arm is exited laterally, no low frequency signal is generated. But it does go out of (offset angle-)alignment ever so slightly for a brief moment.
None of the above has anything to to with reducing the tracing error to zero(sorry) 🙂
Have a great weekend!
Frank
Thanks for the explanation, Frank! Apparently the user in the video does not understand the function of the magnet and has a misinterpretation. Even though the project could be from years ago but the video was posted earlier this year. Someone has been misguided for years.... just like users of the RS Labs tonearm.
RS Labs users even more so. The rotary headshell on RS Labs (and imitators) does not have any restorative 'elastic' force, so not even a chance for any benefit of anti-resonator function.
Ray K
silly doubt
As an enthusiast diyer I love constructions that defy the laws of physics, but sometimes a worm bites my brain: but when the 4 cables section exceeds that of the cantilever (ie always, or almost) who will move first?
Long time ago a quick test gave me the doubt that the only reason the rotary shells work may be that they don't rotate at all. Because of my bad constructions, you know.
St. Thomas
(about bearing, and tip position enough was said)
attachment: plasticized cables on rotary shells
As an enthusiast diyer I love constructions that defy the laws of physics, but sometimes a worm bites my brain: but when the 4 cables section exceeds that of the cantilever (ie always, or almost) who will move first?
Long time ago a quick test gave me the doubt that the only reason the rotary shells work may be that they don't rotate at all. Because of my bad constructions, you know.
St. Thomas
(about bearing, and tip position enough was said)
attachment: plasticized cables on rotary shells
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I would rather agree with Carlo. They do not rotate. There is no momentum for causing rotation, if bearings are coaxial with stylus. My understanding is that bearings work the same way, as spikes ( they strictly limit the vibrational energy transfer to the arm tube), so vibrations stay within cartridge and headshell. For good or for bad, it shouls sound a bit different from average setup.
That on the picture is rotating. King of funny experiment of mine😀
That on the picture is rotating. King of funny experiment of mine😀
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The 4 wires are nothing but another "spring". The distance between the magnet and the opposing iron plate is adjustable, so the lateral "compliance" of the rotating headshell can be tuned to 6 to 14+Hz. Yes, under normal, undisturbed/ideal operation conditions, the headshell does not appear to rotate.
I'm not building anything that defies the laws of physics, I apply them...🙂
Cheers,
Frank
I'm not building anything that defies the laws of physics, I apply them...🙂
Cheers,
Frank
I, too, am a doubting Thomas, and I'm from Missouri. It would be revealing to see a video of the actual behavior of one of these rotary shell equipped arms excited at mass/compliance resonance.
Ray K
Ray K
This headshell attempts to do just that with two springs on the sides but the pivot point is not at the stylus tip though. Now, the question is how do you apply anti-skating to this?
This video and others show the 'elastic' wiggling.
An externally hosted image should be here but it was not working when we last tested it.
hmmm where to begin?
The Nasotec seems very loosey-goosey when the user flicks it, makes me doubt if it has any damping. Frank’s CA when flicked looks more controlled, indicating that his eddy current damping is effective. Also, Nasotec’s pivot point is far behind the stylus tip. Whenever the headshell pivots during play, as it would under conditions of mass/compliance resonance, the stylus will exhibit considerable scrubbing with attendant pitch variation as the effective length of the arm increases and decreases. Anti-skating would be applied as in any other arm that skates. Depending on how stiff the springs are, the Nasotec might even be is its own built-in skate-o-meter! I do recall reading somewhere that the springs are adjustable in order to tune the resonance frequency. But it would seem to rely only on the damping in the stylus suspension or the arm, if so equipped.
Which reminds me, I still want to see a video of these arms playing a resonance frequency test track, not someone flicking the thing with his finger.
Too many videos to comment on every one, but look at the one with the Nasotec on the Clearaudio TQ-1.
YouTube
The carriage “crabs” along as the sticktion builds up and then lets go. Hah! – way more than any servo controlled linear! What about the stock headshell?
YouTube
Less crabbing of the carriage, but now the stylus flexes. Hah! – way more tracking error from stylus flexing than a servo controlled linear.
Here’s a patent issued 40 years ago for a damped anti-resonator applied at the counterweight:
https://www.diyaudio.com/forums/attachment.php?attachmentid=774466&stc=1&d=1565575354
Ray K
My post(#2130) was referring to rotary shells RS like, (no magnets, bearing above tip) as shown in the attachment. Claimed to rotate, correcting residual tracking errors of pivoted TAs.
The doubt came to me noticing that it was strange to commit to make very sophisticated bearings and then to use common short and rigid cables. A quick test, observed with my usual macroscope, confirmed my doubts: fortunately for customers, rotary shells do not turn at all, and Walter's explanation (#2031), cables or not cables, is decisive -- stylus tip in axis with pivot = 0 momentum,
Now these others (#2134): quote RAY #2035 completely, this case is very different because here the pivot is some centimeters behind the tip, and this is a lever.
However, building some PLTs and Linear ones, and more measuring them, I gained some painful experience of the forces involved (2 - 300mg r sin alpha), so when I see those cute springs and that cotton bud pushing ...
Still a basic doubt: why an oscillating headshell (tunable or not)? I know that many decouple the cartridge and all the rest (wives included), to me (and many others) it seems the best way to enjoy all the possible and imaginable resonances, well secured inside the cartridge.
It's a matter of taste, I know.
carlo
The doubt came to me noticing that it was strange to commit to make very sophisticated bearings and then to use common short and rigid cables. A quick test, observed with my usual macroscope, confirmed my doubts: fortunately for customers, rotary shells do not turn at all, and Walter's explanation (#2031), cables or not cables, is decisive -- stylus tip in axis with pivot = 0 momentum,
Now these others (#2134): quote RAY #2035 completely, this case is very different because here the pivot is some centimeters behind the tip, and this is a lever.
However, building some PLTs and Linear ones, and more measuring them, I gained some painful experience of the forces involved (2 - 300mg r sin alpha), so when I see those cute springs and that cotton bud pushing ...
Still a basic doubt: why an oscillating headshell (tunable or not)? I know that many decouple the cartridge and all the rest (wives included), to me (and many others) it seems the best way to enjoy all the possible and imaginable resonances, well secured inside the cartridge.
It's a matter of taste, I know.
carlo
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In my rotary shell (#2131) I've used thin laquered wires, taken off ruined MM cartridge coils. As a result, there isn't any resistance from them, and cartridge turns easily. My intention was to listen, if pivoted shell makes difference in sound. Actually, if put pivot point coaxially with stylus, and carbon brush in front of (the way brush is on picture), it will be able to turn cartridge to correct angular mistake, while it travels across the record. This way we may convert regilar pivot arm into something like PLT by just using a modified headshell.
I'm sure it will work that way to almost annihilate angular mistake. However, it seems to bring other problems, I do not like to deal with. I also do not consider small angular mistake a main problem with pivot arm. Anyway, it was fun.
Actually, the idea of Frank to use magnets instead of springs (in my case it was plastic strip on the top) is brilliant.
Walter
I'm sure it will work that way to almost annihilate angular mistake. However, it seems to bring other problems, I do not like to deal with. I also do not consider small angular mistake a main problem with pivot arm. Anyway, it was fun.
Actually, the idea of Frank to use magnets instead of springs (in my case it was plastic strip on the top) is brilliant.
Walter
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Rotary shell
I've reconfigured my shell by positioning bearing coaxially with stylus, and deleted strip spring. It actually works better, than I supposed, turning by the brush. I will put kind of indicator to see what is going on with angular mistake. By the way, I have an idea on how to make the cartridge to return to proper position for the first track of the record under influence of arm lift.
Later I'll try Mr. Schoeder's magnet arrangement, it is easy to apply here.
I've reconfigured my shell by positioning bearing coaxially with stylus, and deleted strip spring. It actually works better, than I supposed, turning by the brush. I will put kind of indicator to see what is going on with angular mistake. By the way, I have an idea on how to make the cartridge to return to proper position for the first track of the record under influence of arm lift.
Later I'll try Mr. Schoeder's magnet arrangement, it is easy to apply here.
Attachments
When I saw the patent was filed by Matsushita in the late 70s, I knew right away that counterweight patent was applied in a Technics tonearm. Yep, it's the Technics EPA-100 tonearm with "variable dynamic damping."
By the way, I agree with your observations on the videos of the Clearaudio parallel tracker with stock and swing headshells. I saw those videos long time ago and was surprised by its awkward movements. One of the video generated some discussion in another thread. Neither is convincing in accurate reproduction unless it's playing a perfectly centered record and otherwise, yes, a servo arm could do a better job than that.