You´re wrong.
Skating force is most powerrfull at the rim of an LP, descreasing moving to the middle and again increasing towards the
center. Antiskating (optimal) is doing the opposite
.Only arm I know so far doing this corectly is the one TW Acoustics delivers to their turntables.
Magnetic force, adjustable to a center that varies from start, decreases over the record and increases the force
towards the inner grooves.,
The anti-skating force is constant to a first approximation - yes the tracking error will vary by a degree or two, but the cartridge angle is an order of magnitude larger than that at 20 degrees or so. My point was the force doesn't vary proportional to radius or tone-arm rotation - no-one bothers to correct it to second order, that would be overly-complex, knocking down the side-forces by a whole order of magnitude is the point.
For a straight arm to be long enough to have less tracking error than a standard arm with overhang it needs to be very long, about 3 metres from a quick calculation. Longer arms in practice have an angled cartridge and somewhat less tracking error than standard short arm, its not a dramatic improvement, just an improvement, and skating force is not affected much.
If you want to know about the bias compensation, look up the original arm design in the Bizarrm article:
https://www.worldradiohistory.com/UK/Wireless-World/70s/Wireless-World-1977-12.pdf
https://www.worldradiohistory.com/UK/Wireless-World/70s/Wireless-World-1977-12.pdf
That is why, most antiskating mechanisms are wrong.
"First thing we can notice is skating force is not constant and varies according to groove radius."
Here´s (without BS) all the info needed:
Skating force - Misunderstanding and misinformation about it.
I'd rephrase that as "imperfect", but way better than not having one... Low hanging fruit, diminishing returns, the judgement call I'd make is constant anti-skate is good enough - the coeffcient of friction between stylus and disc isn't that well characterized for a start, so you'll never be that perfect. And it definitely varies with modulation depth, something you can't easily correct for. Once the lowest-hanging fruit is somewhere else, your job is done...
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It is a fascinating arm design and easy to DIY.
Arm rotation side to side or up/down puts the viscous fluid in shear and is lightly damped.
Location and resistance to being dragged by the stylus friction is accommodated by the mass of the golf ball and such movement would be trying to displace the fluid from one side of the cup to the other - much harder than the shear in the previous case thus VERY heavily damped.
Arm rotation side to side or up/down puts the viscous fluid in shear and is lightly damped.
Location and resistance to being dragged by the stylus friction is accommodated by the mass of the golf ball and such movement would be trying to displace the fluid from one side of the cup to the other - much harder than the shear in the previous case thus VERY heavily damped.
I think the VOLUME of the golf ball is what determines the damping on translational movement (front to back, side to side) on the horizontal plane when the stylus drags the tonearm. Its volume determines how much resistance will be generated by the viscous liquid. And the force required to move the liquid is related to the volume that needs to be moved and the viscosity. The shape of the enclosure I guess will create some resistance as well but given a large enough cup, I think it doesn't matter too much.
The MASS of the ball likely determines the vertical travel because gravity gets involved, it must be heavy enough to sink into the liquid and not float. I mean the string holds it in place so it won't sink but if for some reason the tonearm is "lifted", it will be the mass that sinks it back down.
Also, the mass of the golf ball likely also affects the transfer of vibrations from the tonearm to the viscous liquid, thus damping the vibrations in the tonearm.
The biggest tweak, the one that concerns me the most is the level of the viscous liquid. How precise must it be?
Otherwise, it is a damn brilliant design the more you think about it.
I might have to get me a used one.... I wonder how easy it will be to ship such a thing... how do you keep the liquid from getting everywhere?
The MASS of the ball likely determines the vertical travel because gravity gets involved, it must be heavy enough to sink into the liquid and not float. I mean the string holds it in place so it won't sink but if for some reason the tonearm is "lifted", it will be the mass that sinks it back down.
Also, the mass of the golf ball likely also affects the transfer of vibrations from the tonearm to the viscous liquid, thus damping the vibrations in the tonearm.
The biggest tweak, the one that concerns me the most is the level of the viscous liquid. How precise must it be?
Otherwise, it is a damn brilliant design the more you think about it.
I might have to get me a used one.... I wonder how easy it will be to ship such a thing... how do you keep the liquid from getting everywhere?
I told my wife no more amps this year.... and that I would only do one big upgrade on the Linn ( which I did ) and one cartridge (which I haven't).
If I got a WT table and put the Grado on it... I got the P2... then put the Fancy Cartridge on the Linn with the P3.
I will have to hide the WT in my office...
The used WT tables are very well priced...
If I got a WT table and put the Grado on it... I got the P2... then put the Fancy Cartridge on the Linn with the P3.
I will have to hide the WT in my office...
The used WT tables are very well priced...
Wishful thinking.
Did you ever adjusted a pivoted tonearm with a protractor? Did you notice how small a change of any dimension sets the tonearm way off the null-points?
The discussed tonearm is CRAP. Okay, if you do not like using strong words - I'll put it a bit mildly - this is the FRAUD.
Did you know that the Tokaido Shinkansen runs the gamut from Tokyo to Osaka... but there's no way to buy a JR pass for only the Tokaido Shinkansen... they make you buy it for the entire JR system. I mean, should you just hop on the Hokkaido and Kyushu Shinkansen just to use the pass?
That's about 1000 bucks for three weeks for a Green Pass. Per person.
And then you still got to pay extra to go from Kyoto to Ise because the local trains are not part of JR.
Now, you might exclaim... "But Tony, that's fraud, that's no really a train pass for all Japan Trains!"
But the trains work really nice... and so does that turntable.
That's about 1000 bucks for three weeks for a Green Pass. Per person.
And then you still got to pay extra to go from Kyoto to Ise because the local trains are not part of JR.
Now, you might exclaim... "But Tony, that's fraud, that's no really a train pass for all Japan Trains!"
But the trains work really nice... and so does that turntable.
I think it's good to realize that any movement of the arm being caused by stylus drag demands elevation of the whole system, the tube, the counterweight, the ball and the cart. Of course at the zero point this force is lowest possible, but what's the exact stylus pull and the force needed to pull the arm by let's say 0.5 - 1mm to make any difference on the arm that long? And if you take a good look at the photo, the wires holding the ball are actually twisted sideways right from the start, providing an extra angle to make the needed pull greater.
From my understanding the silicone oil is there to provide dynamic stability, or in the other words, to act like a damping, so the system is firm against modulated load.
From my understanding the silicone oil is there to provide dynamic stability, or in the other words, to act like a damping, so the system is firm against modulated load.
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- this is a unipivot breed, i.e. it has huge dependance of VTF from the LP thickness and warps. This equals "More distortions"
- as an unipivot - it has NO fixed axis, i.e. all its' settings depend on stylus drag force, i.e. - the groove modulation. This equals "More distortions"
There are more deficiencies there:
- silicone viscosity affects the necessary force for the needle to turn the tonearm
- the tonearm is too long, meaning it cannot provide good tracking of even a slightly warped LP, you will need an LP-flattener of some kind
- the same applies to the LP's excentricity
1. actually it's not unipivot - the ball is suspended on 2 points. It doesn't matter here if the arm vertical movement is suspended by bearings from the bottom or just hanging from the top.
2. The axis is fixed by the weight of the system and the geometry of the suspension by means of static stability and by oil damping further for dynamic stability.
The friction in the fluid caused by arm rotation is proportional to the layer of the fluid between the ball and the edge of the well AND movement velocity. There we have strong layer of fluid combined with extremely slow movement, therefore negligible force.
There again extremely light armtube and cart assembly promises low enough inertia for this to be a concern. Just look how close the counterweight is.
The mention of LP eccentricity is particularly irrelevant here, as the arm length is practically only way to reduce an impact of this on the pitch.
2. The axis is fixed by the weight of the system and the geometry of the suspension by means of static stability and by oil damping further for dynamic stability.
The friction in the fluid caused by arm rotation is proportional to the layer of the fluid between the ball and the edge of the well AND movement velocity. There we have strong layer of fluid combined with extremely slow movement, therefore negligible force.
There again extremely light armtube and cart assembly promises low enough inertia for this to be a concern. Just look how close the counterweight is.
The mention of LP eccentricity is particularly irrelevant here, as the arm length is practically only way to reduce an impact of this on the pitch.
No matter how many strings, the tonearm is free to follow the friction tug.
And I use the "unipivot" word as the derogatory term.
Huge mass has its' center of gravity VERY far from the horizontal axis, any - even miniscule - vertical movement of the cartridge is opposed with huge momentum. If it were possible to place the horizontal axis (about which the vertical "nods" of the cartridge occur) near the CoG, then the VTF would be ~constant during those vertical movements.
But in this tonearm that is not implemented.
And I use the "unipivot" word as the derogatory term.
Huge mass has its' center of gravity VERY far from the horizontal axis, any - even miniscule - vertical movement of the cartridge is opposed with huge momentum. If it were possible to place the horizontal axis (about which the vertical "nods" of the cartridge occur) near the CoG, then the VTF would be ~constant during those vertical movements.
But in this tonearm that is not implemented.
Think of how boring it would be if we'd stayed with cylindrical media rather than changing to discs. So easy to track a cylinder...
This got me thinking about a good analogy that might fit...
The WTA has similarities to a ship anchored in shallow water with a steady tidal flow.
The anchor is the pivot, the boat, the stylus.
The earlier WTA has an alignment protractor provided.
There is also a cartridge mount suggestion as an experiment, to bolt the tonearm to only one side of the cartridge.
Skeptical, I tried it with the solid alloy body MC at the time. It turned out to be the way for the time I had the WTA, sounding better.
Asymmetry!
The WTA has similarities to a ship anchored in shallow water with a steady tidal flow.
The anchor is the pivot, the boat, the stylus.
The earlier WTA has an alignment protractor provided.
There is also a cartridge mount suggestion as an experiment, to bolt the tonearm to only one side of the cartridge.
Skeptical, I tried it with the solid alloy body MC at the time. It turned out to be the way for the time I had the WTA, sounding better.
Asymmetry!