td-01 chinese tonearm?


Has anyone got any info on this item. There is one for sale on ebay right now. Uses a wood tonearm shaft with a ceramic unipivot bearing with a string that seems to center or otherwise hold it in place. Interesting looking design, but I'd like to know more.
manitunc

This TD-01 tonearm seems like a hybrid between a Schroder am and a Well-Tempered arm. I like its simplicity. I would like the string to be shorter and the tie point to be at the center of the ceramic ball - the golf ball in the WTA is the same idea.

Never heard of the sound so I'm curious, too.

http://www62.babidou.com/pic/2010/9/10/tangdan/AAA01-4.jpg

http://www62.babidou.com/pic/2010/9/10/tangdan/AAA01-2.jpg

http://www62.babidou.com/pic/2010/9/10/tangdan/AAA01-1.jpg

http://www62.babidou.com/pic/2010/9/10/tangdan/aaa01%E7%BB%86%E8%8A%822.jpg

http://www62.babidou.com/pic/2010/9/10/tangdan/AAA01%E7%BB%86%E8%8A%82.jpg

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I haven't seen one either. One thing that I would be concerned about is, the stylus always has a different pull/drag on it. With that issue, the arm may move some, causing problems. Hopefully, someone like Stereophile will test one then we'll know more.
where do you think the string goes after it leaves the top of the tonearm. I assume it is attached to the ceramic ball, and that the weight of the arm holds the ball into its oil dampened socket and the string is just used to keep the arm aligned from side to side so it doesnt just fall over. But is that string tied off somewhere, and is the allen bolt on top adjustable to tighten the string?

A nice looking arm, and very simple. Just wonder how it sounds.

the weight of the arm holds the ball into its oil dampened socket and the string is just used to keep the arm aligned from side to side so it doesnt just fall over.

I thought the string hangs the arm and the ball is inside the oil well but not touching the bottom. Instead of using a magnet, like Schroder, to stabilize the arm from swinging all over the place, the designer use an oil bath to damp unwanted movement. I believe this is the same seller who infringed the Schroder patent and Frank took action against it and now he came up with a different design. Instead of magnet, now it's oil. Very similar concept to the WTA.

Your idea would work too but is closer to a classic unipivot design with the assist of a string for stability.

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I'm not sure I'd agree that it's a similar concept to the Well Tempered arm. There can't be more than a drop or two of damping fluid in the well of the TD-01, and the contact area of the ceramic ball is very small. The amount of damping would be miniscule compared to relatively gigantic paddle and fluid well of the WTA. Also, no easy way to adjust azimuth as on the WTA.

Not saying it wouldn't work, or even be better than the WTA; just saying the concepts aren't that similar.

David
I think the ball would have to be solidly in the receiver for this tonearm to work at all, with the weight of the tonearm holding it in place like any other unipivot, otherwise it would be swinging around all over the place. Armstrod is right that there cant be more than a drop or two of oil in there, not like a well tempered that has an fluid bath. And the only way to adjust asimuth would be by turning the counterweight and locking it off center. there must be a way to adjust the lenght of the string so it is tight, but allows the arm to sit firmly in the cup.

By the way, does anyone remember a system that used 3 ball bearings on the bottom in a triangle with one ball bearing in the arm sitting in the middle in a kind of unipivot arrangement that was much more stable than your usual pinpoint pivot?
Manitunc: "By the way, does anyone remember a system that used 3 ball bearings on the bottom in a triangle with one ball bearing in the arm sitting in the middle in a kind of unipivot arrangement that was much more stable than your usual pinpoint pivot?"

I believe you're talking about the Hadcock tonearm. Here's an excerpt from a review in 6moons:

"So, with a blast of trumpets, let's now unveil the £689 Hadcock 242SE. It looks like a conventional unipivot, except it's not. The needle point isn't so much a needle as an elongated cone tip. The cup isn't a cup at all because it holds four tiny brass balls to act as a bearing. So it's a compromise, really - a semi unipivot, its scale reduced to virtually act as a unipivot while producing the greater stability inherent in a dual-pivot design. Very clever, you say - but does it work? Let's find out."


Here's a picture.

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Nope, thats not it. I have a Hadcock and its not what I am thinking of. Maybe a Helius or a Basis Vector. 3 balls creating a triangle, with a 4th ball in the center and raised above the other 3. Maybe I just thought of it?
I think it was the Helius Orion first & the Cyalene later using the 3+1 balls.
I recall some similarities with the old monophonic "Gray" arm that uses grease (instead of oil in the TD-01)
Another thing that differentiates the WT is the great mass at the pivot point.
I think the arm Manitunc referred to was the Wilson Benesch Act 0.5:

http://www.stereophile.com/content/wilson-benesch-full-circle-turntable-act-05-tonearm-ply-mc-cartridge-page-2

Mystery solved. The TD-01 arm does, indeed, work like how I described, ie, the string hangs the arm and the ceramic ball does not touch the bottom of the oil pool and only for stabilizing. Seller responded to question.

Hi, the arm being hung by the string and the ceramic ball is not touching the bottom of the oil pool, thank you! Best regards.


Whether that's a good idea or not is up to the potential bidders to contemplate, I merely described what I observed.

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I would think that there must be something holding the arm in place in the cup other than the ball floating in the oil pool. I would think it was either sitting in the bottom, held by the weight of the arm or the string would go right through, which obviously it does not. the description above makes it sound like the arm is on a pendulum, with the ball just touching the surface of the oil to slow the pendulum action down.

I would hope the ball is actually sitting in the cup and held in place by the weight of the tonearm and the string just provides lateral support.
After reading Q&A's, it sounds like it just hangs and floats. It doesn't sound to stable. To much lateral movement in my opinion. I don't think any is good. It could make odd noises from what I see.
[http://cgi.ebay.com/?ViewItem&item=180623164884]

As I said, this is the same seller who used to have a tonearm that works exactly like the Schroder arm but Frank found out and complained about the infringement to the seller. The designer then put his own twist to the Schroder design by replacing the magnet with a ball in an oil pool a la WTA. Whether the approach is effective or no is still in question.

I don't think it's a problem with the small amount of oil but the tie point of the string is not at the mid-section of the ceramic ball so I believe, as Manitunc observed, there would be too much lateral movement or pendulum action. But if the the ball is touching the bottom of oil pool, there would be no need for the string and simply act like a missionary style unipivot a la Naim ARO or Graham, instead of a spike now it's a ball, which would be similar to a Scheu Tacco. In a classic unipivot, having a string like that would hinder the all kinds of movement, horizontal and vertical. You're better off with no string at all.

This design has much potential but might need further refinement. If any reader has one, feel free to chime in.

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Some odd tonearms to look at from Russia someone posted earlier here on Audiogon.[http://ierihon.com.ua/tonarm]
Someone has too much time on their hands. Some nice woodcarving work on those russian arms, but how could they possibly work with a cartridge swinging from a string?
Well if the RS-1a works.