Has anyone tried to place the armwand ABOVE the glass-tube instead of below, like the Clearaudio TT1? That way the pivot point is closer to the level of the stylus, hence less prone to warp or vertical movement? I know you shouldn't waste time playing warped record per Moray James but I wonder if there's any sonic advantage in this arrangement. The TT1 is the flagship model and the lower models all place the armwand below the glass-tube. Just curious...
An externally hosted image should be here but it was not working when we last tested it.
Directdriver,
I've seen others attempt this, but I've noticed in my own trials you lose a lot of stability trying to place the mass center of gravity above the tube, as you place it all below the tube it seem the cantilever is much less affected by increased mass. There are some spacing tricks that you use to bring warp induced errors to a minimum.
Chokesrule, I'd recommend no more than a 3mm gap between top of wand and bottom of tube, the larger this gap is the more errors on warped records. With this I've setup the tracking with a regular weight record and checked with a 200 gram Record and the tracking on both followed the line perfectly
.
Colin
I've seen others attempt this, but I've noticed in my own trials you lose a lot of stability trying to place the mass center of gravity above the tube, as you place it all below the tube it seem the cantilever is much less affected by increased mass. There are some spacing tricks that you use to bring warp induced errors to a minimum.
Chokesrule, I'd recommend no more than a 3mm gap between top of wand and bottom of tube, the larger this gap is the more errors on warped records. With this I've setup the tracking with a regular weight record and checked with a 200 gram Record and the tracking on both followed the line perfectly
.Colin
Yes, the idea is to have the glass-tube as close to the record surface as possible. The contact between bearing and glass-tube forms a pivot point and in a conventional pivot tonearm, it is desirable to have the pivot point at the same level as the stylus or record level so there's less of a pendulum effect. (Think of Triplanar, Graham, Immedia/Spiral Groove, etc...) I suspect the vertical movement might behave better but as Colin mentioned in this particular linear arm it might affect the horizontal movement and stability, perhaps due to the short length of the armwand. I guess there's a trade off on everything...
Clearaudio tonearm models:
TT3, least expensive: armwand BELOW glass tube.
TT2, more expensive: armwand BELOW glass tube.
TT1, most expensive: armwand ABOVE glass tube.
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There should be a reason why Clearaudio reserve the "armwand above glass tube" arrangement for their flagship product, right?
TT3, least expensive: armwand BELOW glass tube.
An externally hosted image should be here but it was not working when we last tested it.
TT2, more expensive: armwand BELOW glass tube.
TT1, most expensive: armwand ABOVE glass tube.
An externally hosted image should be here but it was not working when we last tested it.
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There should be a reason why Clearaudio reserve the "armwand above glass tube" arrangement for their flagship product, right?
This TT usually uses a perimeter ring clamp for good reason. It doesn,t really matter much the height of pivot since this is bad practice anyway and shouldn,t be considered a viable attempt without some way to flatten the disc. The effective mass would go up the higher the pivot.
I totally agree with you about keeping the pivot point as close as possible to prevent warp/ wow From rearing its ugly head but their are those that will wind up with a flapping woofer regardless since this is difficult to design in.
I remember Southers entry in their own booth back in the Early 80,s ? With there woofers flapping in the breeze wildly without concern for the masses that would soon be accomplishing the same thing at home on TT,s that were far and few between vacuum suction or similiar!
Pointing out their flapping woofers on non bass content LP,s was quickly shunned bt them..! DUH.. Oopps! Auckward
The first priority should be a ring clamp or vacuum with very short pivot arcs.
I have already made a 1.4." pivot to needle Versa dynamics style headshell for my second ET2 air bearing that I would never consider on the usual TT.
I have yet to mount this as it really requires a new tt design in the werks
I,m interested in how it will sound overall.
Regards david
I totally agree with you about keeping the pivot point as close as possible to prevent warp/ wow From rearing its ugly head but their are those that will wind up with a flapping woofer regardless since this is difficult to design in.
I remember Southers entry in their own booth back in the Early 80,s ? With there woofers flapping in the breeze wildly without concern for the masses that would soon be accomplishing the same thing at home on TT,s that were far and few between vacuum suction or similiar!
Pointing out their flapping woofers on non bass content LP,s was quickly shunned bt them..! DUH.. Oopps! Auckward
The first priority should be a ring clamp or vacuum with very short pivot arcs.
I have already made a 1.4." pivot to needle Versa dynamics style headshell for my second ET2 air bearing that I would never consider on the usual TT.
I have yet to mount this as it really requires a new tt design in the werks
I,m interested in how it will sound overall.
Regards david
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Two strips of window pane glass positioned in an open bottom "V" will allow you to position the carriage bearings even closer to the record surface. Far easier to DIY and far less expensive than precession pyrex tubes. Just my two cents worth. Best regards Moray James.
I find the idea of the open "V" channel with 4 or even 2 ball bearings to be troublesome conceptually. The thing wants to "fall" down the hill, as far as I can tell. It just seems inherently unstable?
_-_-
Btw, don't you have to be pretty careful not to scratch the record when putting the record onto the TT with this sort of arm arrangement?
_-_-
Btw, don't you have to be pretty careful not to scratch the record when putting the record onto the TT with this sort of arm arrangement?
sapphire glass
Hi,
looking for a suitable glass tube/rod with perfect surface I found this:
Sapphire tubes / sapphire rods - saphtec.de
sapphire tubes up to a diameter of 50 mm and a length of 650 mm and sapphire rods up to a diameter of 25 mm and a length of 450 mm
Surface roughness · ground Ra < 1.6 μm, · polished Ra < 0.1 μmm.
Have anybody ever considered using sapphire glass, or is this overkill?
Might be expensive.
Regards
Wilfried
Hi,
looking for a suitable glass tube/rod with perfect surface I found this:
Sapphire tubes / sapphire rods - saphtec.de
sapphire tubes up to a diameter of 50 mm and a length of 650 mm and sapphire rods up to a diameter of 25 mm and a length of 450 mm
Surface roughness · ground Ra < 1.6 μm, · polished Ra < 0.1 μmm.
Have anybody ever considered using sapphire glass, or is this overkill?
Might be expensive.
Regards
Wilfried
Or maybe coffee whitener.
I believe this is what the Pro Archers use inside the carbon fiber arrows
Coffee whitener does a good job but it is very hygroscopic. In a damp basement or climate climate it turns to concrete. OK if you have a metal or impervious material for the shaft and seal the ends and any openings for wires. Been there, done that.
BillG
Moray,
The open V is very different than a continuous curve.
While it is true that there is a tangent to any point along a curve, that tangent is only valid for that precise angle, which corresponds only the the position of the arm at that moment.
The curved glass works because the change between where the arm is now and where it needs to move to (in the vertical axis) along the surface of the glass next is always the same change.
So, the force required to make a change in position is always very much similar, if not identical. Whereas with an open "V" it is clear by observation that the more the bearings move, the less similar (less linear) the force required for restoration *back* to the starting position. With the "V" once the arm has moved in the vertical position more than a very little amount, it will "avalanche" and require one to lift the assembly up to reposition it. Not a system I would want to use myself.
Sitting on top of a curve with 4 bearings, or sitting inside a curve with two or 4 bearings is intrinsically stable. Sitting on the slopes of a "V" shape is intrinsically unstable.
The open V is very different than a continuous curve.
While it is true that there is a tangent to any point along a curve, that tangent is only valid for that precise angle, which corresponds only the the position of the arm at that moment.
The curved glass works because the change between where the arm is now and where it needs to move to (in the vertical axis) along the surface of the glass next is always the same change.
So, the force required to make a change in position is always very much similar, if not identical. Whereas with an open "V" it is clear by observation that the more the bearings move, the less similar (less linear) the force required for restoration *back* to the starting position. With the "V" once the arm has moved in the vertical position more than a very little amount, it will "avalanche" and require one to lift the assembly up to reposition it. Not a system I would want to use myself.
Sitting on top of a curve with 4 bearings, or sitting inside a curve with two or 4 bearings is intrinsically stable. Sitting on the slopes of a "V" shape is intrinsically unstable.
My guess is that this is overkill and unless the items are inexpensive, unnecessary.
One might compare three things. The surface roughness/smoothness (not the same things) of glass tubing, ground/polished glass tubing, and the surface roughness of the bearings (in all regards, and especially the outer surfaces).
Otoh, smoother is likely to have less vertical axis sliding friction, which would be nicer, unless there is an issue with too little friction there causing too little damping.
But it does sound like a very nice product. What sort of price are they asking, I'd expect they are rather expensive given what I think a single sapphire ball costs?
Regarding the pivot point for the Opus, this one, or the CL's, the pivot is the center of the tube regardless of the bearing arrangement. Unless, of course, it is a knife edge bearing.
Over the tube tone arms do allow the support rod to be closer to the platter, with a lower pivot at a trade off. You have to lift or move the tonearm out of the way for an album change.
Over the tube tone arms do allow the support rod to be closer to the platter, with a lower pivot at a trade off. You have to lift or move the tonearm out of the way for an album change.
I had tried the V once, but only with aluminum v channel in my original attempts both in the channel and on top of the A and got interesting results. Firstly it made it necessary to use larger bearings, 12mm min, and horizontal movement would get sticky if there was even the slightest microscopic imperfection, vertical movement was also inconsistent so much so you could feel it moving the arm by hand, never tried glass though as I ruled it out due to its inconsistentcy prematurely in operation. That was prior to the four bearing idea, in this case allowed me to use much smaller bearings down to 8mm and a brass rod for trials, this proved to work very well. After this the obvious choice was glass tube, and with borosilicate or quartz this stuff is so hard you can slide a sharp knife across it and not scratch it. I find the benefit of riding the tube is as Bear points out is that vertical damping remains the same as the arm traverses warps, if you look at a v with a bearing riding in it damping will change as the arm rides even a slight imperfection due to the changing contact area and angle in a v, whereas vs round glass the same points will only slide over the tube with consistent damping and recovery. This in return takes the vertical heat off of the cartridge suspension as I've found.
Colin
Colin
Colin, Bear, and others,
Comparing a V track of window glass using 2 bearings with a 4 bearing over the tubular track of borosilicate glass and drawing conclusions seems to me comparing apples and oranges and wondering why a pomegranate is different. My success with the V certainly says that there is some merit to the scheme. There were definitely some aspects of its performance that caused me to try an outside the tube 4 bearing design. The results of that trial are that I will not go back to the old design.
The analysis that you put forth fails to consider the action of the bearing radial play which makes the satisfactory performance of any 2 bearing design possible. I have a few warped records and for the most part they never cause the vertical displacement to exceed the limits of the radial play. I think the recovery provided by the radial play is actually faster than that of the "on the tube" version. (For the 4 bearing design I don't see any radial play possible.) When it does exceed those limits the tubular track version is better. I do not believe I have ever heard any degradation of the sound because of it. For a more apples to apples comparison I think we should look at a much shallower V and borosilicate rather than window glass. I think the coefficient of friction for the window glass could be much higher. The surface uniformity hardness and polish of the tube is far better than the window glass. Nevertheless the V was a great experiment and still can provide a tonearm with superior performance to many pivoted designs.
Long live linear trackers!
BillG