Gliding for 90° - mechanical linear tonearms: no airpump, no servo

There has to be a way to get that 90º on a stylus without the damn air pump and servo!

To avoid hijacking other tonearm threads so I decided to start a new thread focusing on the discussion and design ideas for non-airbearing, non-servo style tonearms that can attain tangential tracking, mechanical linear tracker if you will. And for those interested in pivoting tangential tonearm, there's already a thread available in this forum.

This is purely an intellectual exercise and for entertainment only so this is not a "project" thread or step by step work in progress thread. You can provide your own DIY projects as examples of course as exhibited in other threads. Here, I try to accumulate as many images, graphics, diagrams, patents, and concepts as possible in one bundle so future experimenters can glean from it. Free free to chime on this topic without fear of going offtrack.... as little talk of airbearing, airpumps, computer servos, etc...if possible just to give this thread some focus since those threads are littered on the internet already. Other than that, welcome all!

I wanted to started off historically but my perspective on the topic is rather random so I will just post pictures randomly. Feel free to post pictures you find pertinent to the topic but please try NOT to download pictures and then upload to here. Simply use html or link the image in "" form so you won't violate any copyright.


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Let's start with one of the grand daddies of mechanical linear tonearm, the Souther tonearm by Louis Souther. And his patent.


-8309-L.jpg




. . . . . . to be continued . . . . . .


:)
 
Bajulaz tonearm

If one go back further in time, here's one qualified as a glider that's mounted on a Thorens TD-124. According to this webpage it's called a "Bajulaz" tonearm:

Prototype of the 'Bajulaz' tonearm on a TD-124. It was designed by Ing. Bajulaz to overcome the geometry problems of the conventional tonearms, but allegedly it wasn't so good for the new stereo cartridges and therefore never went in production. Thanks to a Swiss enthusiast for the picture and the history of this fascinating machine.

An externally hosted image should be here but it was not working when we last tested it.
 
Ortho-Sonic V/4 tonearm

Thanks Frank, for alerting us of this rarity!


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


Clearly this shows the use of four ball bearings each side angled 45º to the single rod so there are four contact points and the vertical movement will be riding up and down on this rod. Reminds me of the bearings on a printer.

$_57.JPG


$_57.JPG


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


$_57.JPG


$_57.JPG


$_57.JPG


$_57.JPG


$_57.JPG


$_57.JPG


$_57.JPG


$_57.JPG



- - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Another one for sale.


$T2eC16V,!w0FIZy0RgfVBSLi6GKwJQ~~60_57.JPG


$T2eC16d,!wsE9suwywR(BSLi6JrFww~~60_57.JPG


$(KGrHqJ,!qYFIOF7+PLSBSLi6Pm0Zg~~60_57.JPG


$T2eC16F,!ycFIdW(LG6vBSLi6TPNEQ~~60_57.JPG


$(KGrHqR,!mIFIm4WfS,QBSLi6ZijIQ~~60_57.JPG


$T2eC16V,!)0FI,SWd7OcBSLi6c!NFw~~60_57.JPG


$T2eC16F,!)EFIpjbkTeGBSLi6fOUWg~~60_57.JPG



- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

From another forum.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
Last edited:
Theorizing and testing

I'm posting a photo of my 'almost finished' mechanical linear tracking tonearm derived from the original work of Colin in the "DIY Linear tonearm" thread. There are other photos of mine, posted today, at that thread; and, in time, a full report on my arm OTF VTA linear arm.

-----

Here, given the issues related to 'theorizing' brought up in that other thread, I'd like to relate (briefly) an academic take on the nature of science and theorizing - which I learned many years ago at the University.

"Science" makes two fundamental assumptions about reality:

1. There is order in the Universe.
2. Humans can determine that order.

So science is a belief system. Science grew from noble origins in 'empirical testing' to the current 'hypothesis testing' model, wherein 'theories' are tested by making predictions of the outcome of 'controlled' experiments.

Without testing, how does one separate metaphorically 'the wheat from the chaff'? (Or, scrape that B.S. right off your boots.) History is replete with examples of armchair theorizing being disproved via actual testing. In that other thread, a 'theorist' told me that my 4-bearing linear tracking carriage would only track on three bearings. Yet I could see, via marking the bearings outer wheel, that all four bearings moved equally.

It is very hard to build and test, and very easy to theorize.

Ad Astra,
John
 

Attachments

  • tonearm radial setup.jpg
    tonearm radial setup.jpg
    54.2 KB · Views: 591
It is very hard to build and test, and very easy to theorize.

Points taken, John. I elaborated on the other thread so from now I will rest on the topic. And those who know me in this forum prefer me to continue to provide more tonearm porn, err, entertainment for the DIY community. :)

Thanks for contributing the picture of your impressive project. I like the simplicity of it and quite elegant. I notice the counterweight is hung on a string so that reminds me of the Roksan tonearm's Intelligent Counterweight.

.
 
1910 acoustic passive linear tracker phonograph

Speaking of grand daddy lineage [no pun intended], I came across this 1910 patent for a passive linear tracking pickup for the horn on an acoustic phonograph. The patent even describes tilting the the platter and pickup, presumably to overcome some of the 'sticktion' of the rollers on the two parallel tracks - a concept I've seen mentioned in another thread.

The U.S. patent number is 948,959.

Methinks too much VTF for vinyl, though.

Ray K
 

Attachments

  • 1_Pat#0948959 1910 LT.png
    1_Pat#0948959 1910 LT.png
    29.1 KB · Views: 747
  • 2_Pat#0948959 1910 LT.png
    2_Pat#0948959 1910 LT.png
    93 KB · Views: 681
  • 3_Pat#0948959 1910 LT.png
    3_Pat#0948959 1910 LT.png
    78.7 KB · Views: 669
There has to be a way to get that 90º on a stylus without the damn air pump and servo!

To avoid hijacking other tonearm threads so I decided to start a new thread focusing on the discussion and design ideas for non-airbearing, non-servo style tonearms that can attain tangential tracking, mechanical linear tracker if you will. And for those interested in pivoting tangential tonearm, there's already a thread available in this forum.

This is purely an intellectual exercise and for entertainment only so this is not a "project" thread or step by step work in progress thread. You can provide your own DIY projects as examples of course as exhibited in other threads. Here, I try to accumulate as many images, graphics, diagrams, patents, and concepts as possible in one bundle so future experimenters can glean from it. Free free to chime on this topic without fear of going offtrack.... as little talk of airbearing, airpumps, computer servos, etc...if possible just to give this thread some focus since those threads are littered on the internet already. Other than that, welcome all!

I wanted to started off historically but my perspective on the topic is rather random so I will just post pictures randomly. Feel free to post pictures you find pertinent to the topic but please try NOT to download pictures and then upload to here. Simply use html or link the image in "" form so you won't violate any copyright.


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Let's start with one of the grand daddies of mechanical linear tonearm, the Souther tonearm by Louis Souther. And his patent.


-8309-L.jpg




. . . . . . to be continued . . . . . .


:)

I saw you have a micro seiki RX1500, Is it a FVG? I made to this turntable deep changes. I want to share.
Best Regards
 
Speaking of grand daddy lineage [no pun intended], I came across this 1910 patent for a passive linear tracking pickup for the horn on an acoustic phonograph.

Nice! It's truly a grand daddy! In fact it's older than my real grand daddy! :D

I saw you have a micro seiki RX1500, Is it a FVG? I made to this turntable deep changes. I want to share.
Best Regards

It's not my turntable but pictures are taken from this website and you can contact site owner for more info. If you want to share your pictures and thoughts on the Micro Seiki, feel free to post here or start a thread. Enjoy!
 
I love the Souther arm. I have 2, and have one on my SOTA table, with a WIN strain gauge cartridge. Amazing sound.

But there are a couple of design flaws in the Souther that I have tried to fix up in a DIY fashion. These are:
1. crappy cartridge leads and too many connectors
2. The arm sits on the spindle
3. Cheap plastic top cover
 
For the cheap cartridge leads my solution is simple - I have assembled 2 runs of twisted pair cable, made from 0.125mm winding wire. At one end I have soldered cartridge clips onto the wire, at the other end is a pair of RCA plus. The cable is carefully dressed to avoid any drag on the cartridge, following a similar path to the old Souther layout. One piece of very thin single core cable, from the cartridge to the pre-amp - what could be better.

cartridge leads.jpg
 
I hate the thought of the arm sitting on the spindle - while friction is assumed to be low i am pretty sure that there must be some noise getting into the system. I think I first saw this idea on a Clear Audio arm, I have put on small block of wood on the plinth right next to the base of the souther. There is a T nut in top of this block and a bolt that screws in and out (with a flat head). The end of the arm carriage, closest to the pivot, rests on the top of the bolt when the carriage is lowered across the record. I have removed the spindle locater from the other end of the arm carriage. The bolt is screwed up or down to level the arm carriage.

leveller.jpg
 
To replace the cheap plastic top plate, my mate who was using my spare Souther fabricated a new plate made from lead. The extar weight and stiffness of the lead, compared to palstic, has a significantly positive impact on the bass - it goes deeper and is tighter. The only problem with this approach would be unbalancing the suspension if you use a suspended deck, but as my SOTA is no longer suspended (that is a story for another day) it is no problem for me.

top plate.jpg
 
1. crappy cartridge leads and too many connectors
2. The arm sits on the spindle
3. Cheap plastic top cover

Thanks for the photos and explaining your mods to the Souther. I totally agree with problem #2. I was bewildered by it the first time I saw a Souther that a tonearm would sit on a MOVING part! Glad that you're able to fix the problem. At least Clearaudio addressed the issue. But I'm curious why they never consider using a pivoting base like the one in the Versa Dynamic arm. A tiny magnet can be added to lock it when the arm is swung in play position and I believe it's a bit more user friendly than the raised bridge style assembly. I guess the bridge style arm looks more visually impressive to the buyer.