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

[directdriver]

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 "[IMG][/IMG]" form so you won't violate any copyright.


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






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

[directdriver]

[directdriver]

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 no longer works. Please upload images instead of linking to them to prevent this.

[directdriver]

It pivots and glides.

[berlinta]

Hi,
If Lou Sowthers arm is the grand daddy of linear tt trackers, what do you call the 1956 Orthosonic V/4 :-) ?

Lots of pics on the web, one for sale(no affiliation with the seller...:-)

RARE Vintage Ortho Sonic Tonearm V 4 Linear Tracker Tonearm | eBay

Cheers,

Frank

[directdriver]

Originally Posted by berlinta

If Lou Southers arm is the grand daddy of linear tt trackers, what do you call the 1956 Orthosonic V/4 :-) ?

Another good one, Frank! It would be the great grand daddy of linear tracker! Better not show it or else that German company Cloneaudio decides to copy it!

[directdriver]

Thanks Frank, for alerting us of this rarity!


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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.





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Another one for sale.

















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From another forum.

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.

[John ALSR]

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.

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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

[phivates]

Easier still to criticize

[directdriver]

Originally Posted by John ALSR

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.

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