Like Albert, I've been through a few arms too. I like the *idea* of LT, and have had a few. But- I found myself preferring a uni-pivot (the Graham) and ultimately the Triplanar over that.
I still want to see an LT happen though. My feeling is that the air-bearing approach is fundamentally flawed, as the lateral tracking mass is several times higher than the vertical tracking mass (which is about the same as a radial tracking arm). You need a *really* low compliance cartridge to make that work, otherwise you get tracking distortion as the cantilever sweeps back and forth.
In addition, the more pressure you put in the bearing the better it sounds. Here is a fundamental rule about LP playback:
There can be no bearing slop between the platter spindle and the cartridge cantilever. The coupling between these parts must be absolute! (BTW, any of you that ride motorcycles will recognize this rule, it is the same one that says there will be no slop between the handlebars and the rear wheel, if you want the bike to handle safely).
Air bearings break this rule, as a result, you can always get them to sound *better* but you can never get them to actually work completely right- and so they can be shown up by a radial tracking arm, which simply should not be.
There is a solution. There are motion devices that have zero slop in their bearings. Some are small enough to be used easily in a tone arm, solving the Rabco track issue. One problem that the old Rabcos had was excessive slop in the track and there was nothing you could do about it (in addition there were a host of other problems- I had one of these for years and solved some of them, but some were fundamental to the design and could not be solved).
The kind of arm I am talking about currently does not exist. But- if you used one of these tracks and installed a modern arm tube/bearing system on it, and then an updated electro-mechanical means of arm advancement along the lines that Rabco made, you could make something that would work really well. I've been thinking about this ever since I got rid of my Rabco 20+ years ago... :)
Until then I'm using a radial tracking arm and its awesome. It is so nice to put on a record and not fear any tracking issue, any dynamic range; just have the music emerge (and buy more records) :) |
There are extremely high tolerance, precision, liner bearings(air and otherwise) & linear motion slides used in optics & robotics/automation in semiconductor equipment, fiberoptics, photonics industries that would seem to be a perfect match for TT use.
As to whether they have been shrunk to a usable size or cost is another thing. |
The physics regarding some weaknesses of linear design is plausible,but "man" do some of these things sound good!!!
Btw,I had a friend who owned,and loved,the "Versa".It sounded very good,but it almost never got through an LP without sticking,or something like that.So,I definitely buy into Atmosphere's comments.....as usual.
Best. |
loved the "Versa" It sounded very good, but it almost never got through an LP without sticking, or something like that. Humidity in the air would condense due to the high pressure in the Gast aircraft compressor used in the Versa pump. When this humidity filled the air lines it clogged the bearing and sometimes (literally) even dripped condensation (water drops) onto the LP from the air bearing surface. Obviously this is when it would stick. The Air Tangent did not have this problem, nor did the Walker. Lots of factors go into each of these designs and even though I can still "hear" each one in my head, there are good and bad about each. |
THK has a patented linear motion slide that is the perfect size for a linear tracker, has low sticktion and guaranteed no bearing slop. All one would have to do is put gimbled bearing and an arm tube, and...
I've stayed in the amp side of the business for a reason :) |
08-01-08: Atmasphere
THK has a patented linear motion slide that is the perfect size for a linear tracker, has low sticktion and guaranteed no bearing slop. All one would have to do is put gimbled bearing and an arm tube, and... Last year, I spent a lot of time researching the new air bearing materials like the micro-porous blocks used in precision automated linear slides. Never could get around the noise effect of high-pressure air in a quiet listening room. Low pressure system have their own drawbacks. These precision roller slides by THK look really nice. I wonder what their lateral friction or resistance is like? Seems to me that their servo actuator systems would have to be highly precise and smooth in order to be used in precision optics grinding and semiconductor fabrication. Oh, and back to SPL's original question: 1. Do you consider linear Tracking superior to Unipivot?
2. Which would you say is harder to set up properly? As a novice vinyl fan, I found my Cartridge Man Conductor linear air bearing tonearm to be easier to setup and fine tune than my Scheu Tacco sapphire unipivot. |
I think it's impossible to separate the turntable from the arm, particularly when some of the best turntables (Kuzma Stabi, Rockport, Walker, Versa Dynamics) all come with linear arm fitted during assembly and there is typically no way to fit a pivot arm on one of these to make a comparison. A clarification. That may be true of Rockport, Walker, and Versa Dynamics but is not true of the Kuzma Stabi XL and Stabi Reference turntables, which may be fitted with the Airline, 4Point, Stogi Reference, etc. as well as third party arms, and the XL can accommodate as many arms as desired and practical. Dealer disclaimer. |
I've had a THK slide sitting around for a while. Its low sticktion and lack of slop makes it an ideal candidate for a proper TL arm. Its also an ideal size. |
Just in case anyone is looking to explore the viability(and affordability)of a nice LTT arm,I found a very reasonably priced design by searching around the web.... There is a link on Arthur Salvatore's site,but it can be found [email protected] The arm is called "The Terminator",and there is a nice review(one I read awhile ago,which caused my own curiousity and interest). The reviewer kinda goes "bananas"(a good thing)over the arm,and loves it... The price looks to be quite low,for a "supposedly good" Linear Tracking Arm...it's 470 British Pounds,plus 15 British Pounds for shipping.The user(if located in the U.S.)is supposed to buy the air pump though.A decent pump should be quite inexpensive,if I correctly understand the information given. Please understand I am ONLY trying to give some information about LTT arms that won't break the bank(for those interested parties)in price,and it is ONLY hobby talk!! Personally I am not about to abandon my unipivot,but certainly do appreciate the alternative sonic benefits that the LTT's can offer.....I envy those(like T.H.)who can run multiple arms/cartridges....Something I never used to even think about,but do now.....Lucky dogs -:) Good luck |
Here's a link to TransFiAudio's eBay page. But, we should also mention the AirTech MG-1 air bearing arm that got some attention around hear a couple of years ago. The price is still around $600. If you do a search here in the Analog section, they quite a few members who bought one. |
Darkmoebius, I must admit the Scheu Classic arm was a lot of work to setup and it sounds wonderful on the Scheu Premier. For now I can sit back and enjoy the music with no fuss to tweaking the arm until I decide to change cartridge. Which incidentally I did right after getting table. I swapped out a Scheu/Benz for a Clearaudio Sigma and the results are fine indeed.
Another, point a friend made who is an ex-Stereophile writer, is that arms such as the ET 2 need constant care in all parameters to maintain good accurate playback. I have heard this arm and it sounded great, but this was many years ago. Since then I have heard so many arms it makes my head spin. Regardless, this forum is very informative to a sophomore such as myself. |
Spl,
I bet the Classic is killer with the Premier, it seems T. Scheu really knew what he was doing. The Tacco is superb once dialed in, but also a bear to fine tune.
Quite a hobby we've picked.... |
Incidentally, I have thought about using an LT with the Scheu Premier. Any recommendations? Naturally, I would have to make separate base, can this work?. LT arms to consider, Air Tangent, ET 2, Clearaudio and Airtech MG-1.
Quote from
Cjfrbw
I spent some time playing with one of John Elison's spreadsheets from vinyl asylum, plugging in values for tracking error for pivoted arms. I find it difficult to believe that a properly set up pivoted arm, even a 9 inch arm, has enough error to significantly "hear" the tracking error unless the arm is not set up correctly. I tend to think the audiophile imagination "knows" there is some tracking error and runs rampant to fill in the blanks to believe that 12 inch arm and linear trackers are audibly superior "because" of the geometry advantages. If somebody states they can "hear" the superior qualities of a linear tracker vs. a properly set up pivoted arm, I would be very skeptical. |
BTW, that Cartridge Man Conductor LT looks to be
beautifully engineered, must sound great. |
I've used an ET2 now for 11 years. In many ways it can still offer state of the art sound, and relatively inexpensively for those looking. I'm certain it has it's flaws, but I know I've mentioned elsewhere on these forums that I just can't be beat for groove distortion, especially towards the end of an lp where grooves are tighter.
I like the look of the "Conductor" tonearm and hope it does well. It seems to offer a reasonable alternative to the big boys of pivoted design.
On some comments regarding tracking error made above, I wonder if those who can't hear .8 of a degree of error can hear the differences in cables???? |
Alun, the problem with many air bearing tonearms is that the lateral tracking mass is much greater than the relatively normal vertical tracking mass.
This causes the cantilever of many cartridges to 'walk' back and forth as it produces all the forces needed to move the excessive mass of the arm toward the center of the LP as it spins. The result is that often the tracking error caused by the cantilever bending is much more pronounced that that of a radial tracking arm. This can be reduced by using a cartridge that has less compliance but you run into troubles with the effective mass vs the mechanical arm resonance (which is usually between 7Hz - 12Hz for best results).
A linear tracking arm that relies on a servo to move the rear tone arm will have a much lower tracking error and no need for a low-compliance cartridge. The Rabco was one of the few arms to use a system like that, but otherwise was a terrible arm. The 1960s for the most part was not a good time for tone arm designs :) |
I only been using a linear tracking arm for a few months before then I had a silver wired SME 4 and to be honest the Terminator is just in a different class in every department. It has no hiss coming through the carrier
I am now totally convinced that this is the way to go to get the best out of your turntable |
A linear tracker is theoretically perfect at tracking whereas with a pivoted arm that is impossible. That ends the whole debate. Whether or not one can hear the minute tracking errors is a whole different debate.
And it's tiresome reading all the miss information about linear's or more specifically the ET2. It has great bass when set up properly with a proper air supply and it does not require constant fiddling. |
AL, The operative word in your first sentence is "theoretically". Yes, an SL tonearm is theoretically perfect, but it is never actually perfect, which is one reason why the SL type does not completely dominate the high end of the market. The other major reason, IMO, is the need for a pump, the problems that come with that (noise, moisture in the system, etc, etc), and the problems associated with trying to achieve elusive perfection. But I would agree that among SL tonearms, the ET2 is clearly a winner, along with a few others.
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