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Old 2nd June 2017, 03:09 PM   #1191
directdriver is offline directdriver  United States
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Default Schuchtronic tangential tonearm 2017

Looks like Schuchtronic completely dispense the pivot headshell tonearm and created another "string" tonearm with a different concept. Very unique and nothing quite like it! Check out the two YouTube videos below:

"Zero tracking error turntable arm 001"

"Zero tracking error turntable arm 002"

The patent is in German, in case you want to study it.

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Old 2nd June 2017, 03:20 PM   #1192
billshurv is offline billshurv  United Kingdom
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Dunno how well that works, but it looks great. Shame he ruined his demo model with the cheapy headshell.
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Old 3rd June 2017, 09:39 AM   #1193
super10018 is offline super10018  United States
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I can't say that I fully understand how the arm works. But as long as the driving force is generated by the interaction of cantilever and groove, the cantilever will endure stress. The question is how much. The only kind of arm will not put stress on the cantilever is an active servo arm with precision eccentricities tracking.

Not tracking eccentricity is a compromise due to lack of appropriate technology. In theory, not tracking has no advantages over tracking. In reality, not tracking may have the advantages over tracking, however, it is a compromise.

Air bearing does track eccentricity passively. For air bearing arm, to find a right combo of cartridge compliance, right damping, right mass and right construction will reduce cantilever stress to avoid under shoot and over shoot.
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Old 3rd June 2017, 09:18 PM   #1194
diyrayk is offline diyrayk  United States
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I looked at the YouTube videos and the patent. Don’t know German but you can get the gist of how it works from the patent drawings. It does appear to be different. Figure 1 is an implementation with rollers (3.11) and is good for visualizing the concept. Stylus trajectory would be determined by the curve characteristic of (2.2).
Figures 2, 3 and 4 look like the production model, except that the production model appears to have an added refinement in that the rear rod rests directly on the curved ‘wall’ (2) and does not rely on string tension alone to restrain fore/aft movement of the entire arm.



Figure 5 was the ‘light bulb turning on’ showing how the vertical pivot was implemented. The vertical pivot axis is between the left end of string (3.7) and the right end of string (3.4). The relative tension of these would determine pivot height and cartridge azimuth. The tension of these two strings holds the back rod against the curved surface of ‘wall’ (2), and forms a pseudo horizontal pivot that ‘rolls’ along the backside of (2). There is a third string adjustment in the post #1191 photo that I haven’t figured out yet. Anyone?


I have concerns about strings (3.7) and (3.4) under tension vibrating as in a guitar or piano, but there is something that concerns me more. Note that the effective offset angle of the arm varies considerably across the disc playing area as the arm’s vertical pivot ‘rolls’ on the curved wall. Just eyeballing the dimensions in the photograph, the effective offset angle at the outer grooves looks like it could be something on the order of 40 degrees, which would make for some horrendous skating forces and cantilever stress. Does anyone see anti-skate compensation anywhere? I don't.

Ray K
Attached Images
File Type: jpg Patent Fig1.JPG (74.7 KB, 348 views)
File Type: jpg Patent Fig2.JPG (71.2 KB, 361 views)
File Type: jpg Patent Fig3.JPG (60.1 KB, 357 views)
File Type: jpg Patent Fig4.JPG (65.1 KB, 364 views)
File Type: jpg Patent Fig5.JPG (38.3 KB, 364 views)
If more is better, then too much is just right.
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Old 4th June 2017, 02:00 AM   #1195
directdriver is offline directdriver  United States
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Thanks for doing all the leg work, Ray! At first the figure 1 picture looks familiar and it reminds me of something I saw in a patent so I went back to past posts and then I realized the new Schuchtronic arm has a predecessor!

Here's an arm conceptualized by an inventor from India, Dwipendra N. Guha, in patent US3973778 and it's covered from post#288 to post#294. And the consensus is that an arm like that would skate like crazy! And Straight Tracker, Ralf, wagered that Guha never made even a prototype. It's agreed that geometrically the Guha arm is also a Birch variation.

Click the image to open in full size.

Click the image to open in full size.

I never figured out how the Guha arm works and I eventually forgot about it. And now the Schuchtronic arm is even more bewildering. At least Schuch made a prototype. I'm not sure how it overcomes skating force. But I love this kind of thinking outside of the box inventions! This thread is about creativity and intellectual amusement. It's fun and thanks for indulging me!
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Old 8th June 2017, 09:08 AM   #1196
lcsaszar is offline lcsaszar  Hungary
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One can tune the strings with the golden keys to different pitch
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Old 8th June 2017, 06:15 PM   #1197
stevieg is offline stevieg  United Kingdom
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I thought at first sight that the gold/brass curved piece was a hipflask! This is such a wonderful thread.

Cheers Steve
if it ain't broke, I ain't fixed it
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Old 8th June 2017, 09:15 PM   #1198
directdriver is offline directdriver  United States
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Originally Posted by stevieg View Post
I thought at first sight that the gold/brass curved piece was a hipflask!

...and toned arm.

Click the image to open in full size.

Click the image to open in full size.

Last edited by directdriver; 8th June 2017 at 09:18 PM.
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Old 8th June 2017, 11:40 PM   #1199
directdriver is offline directdriver  United States
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Default early AK1 or AK1/2?

I found a picture in another forum of an early developmental model of the Funk Firm AK1 in 2015 and it was called the Grand Prix tonearm. Looks similar to the current one but the strings are crisscrossed. The discussion unfortunately focused too much on its exorbitant price. I'm glad this forum talks more about designs and ideas than pricing and marketing.

The surprising information is that the arm is the result of an early collaboration with the designer of the early Schuchtronic tonearm, the stringed pivoting headshell one, not the string tensioned 'hipflask' one. This Daniel Schuch guy apparetly loves playing with strings!

The actual inspiration for that visually obvious feature (string) was a German arm exhibited at Munich in 2013 by Daniel Schuch. Daniel and Arthur discussed collaboration, but nothing came of it. The problem with the Schuh arm was that whilst it achieved the geometry, structurally it was "less effective". AK had his ideas for tackling the structural issues, which are the core of the F1 idea, but without wanting to be too coy "the gizmo" even more than the materials works well with this variable geometry idea.
Click the image to open in full size.

Maybe a revival of another stringed arm.... the DIY way!

Click the image to open in full size.

Last edited by directdriver; 8th June 2017 at 11:44 PM.
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Old 10th June 2017, 07:49 PM   #1200
dtut is offline dtut  United States
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A couple of thoughts about the Schuchtronic and Guha arms: The Schuchtronic is so goofy/unique that I really hope it works despite one or two theoretical problems. From a DIY perspective, how can anybody not get a kick out of guitar string tuners repurposed despite concerns about string resonances?

The double bearing arm in Fig. 1 is clever, but will probably have binding issues between the bearings sides and the groove sides. That can be mitigated with very precise wheels and grooves, but that puts the construction well outside most DIY. I'd liked to have been around when Daniel Schuch realized he might be able to achieve the same design with strings. In both designs, he seems to have used an elliptical arc - Schroeder - instead of a circular arc - Birch - which might lead to nearly perfect tangency. I share Ray K's concern about the offset. I wonder if there might be a virtual pivot that alleviates that problem.

Without string 3.6, the whole thing will collapse. It provides the second leg of the triangle that supports the outside end of that segment of the arm.

I thought the Guha arm rotated control point B in the Birch geometry 90 degrees and a quick drawing I did yesterday seemed to confirm that, but today, after doing another drawing, it's clearer that the control arm slip/slides across the circular surface. One advantage the Guha arm would have over the Birch is that the plinth could be smaller although it shares the disadvantage of the headshell being parked quite close to the platter edge.
Doug Tuthill

Last edited by dtut; 10th June 2017 at 07:51 PM. Reason: missing 's'
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