[78-L] Co 113a Alignment issues

[Mark Bardenwerper]

On 1/15/2017 9:55 AM, Iñigo Cubillo wrote:
> Ron, and all:
>
> I've taken several photos, as best as I could, to illustrate the geometrical
> issues with the Co 113a tonearm. The images are self-explainig, and I tried
> my best to underlay a paper with master lines traced so the real thing can
> be examined. I also show the 65 degree (more or less) achieved due to the
> self-made rubber back joint. There is also a typical geometrical diagram
> showing the general principles of tonearm alignment. The photos show how the
> Co 113a tonearm is aligned when a 65 degree zenith is fixed.
>
> Of course, the solution for this case is to provide an inwards angle to the
> soundbox (what is the same in the end, more offset distance). Otherwise, the
> distance between the spindle and the tonearm pivot should be modified, but
> this implies modifying the motorboard, etc.
>
> Thus, by trial and error one can try smaller modifications to improve the
> tracking as possible, by a wedged joint, a trunnion connector between
> soundbox and tonearm, etc. These things would not seriously modify the
> machine while improving the tracking error.
>
> Here is the link to the images;
>
> https://app.box.com/s/0wktmfsjx3mokqofiwbvtffm9nfab4dh
>
> Hope this helps...
>
> Inigo Cubillo
>
Hello Inigo,
I think you have made some significant improvements to a machine that 
was probably best intended when it was sold new to make some money for 
the seller and little else. Imagine the number of companies competing to 
sell these portables were not very interested in fidelity or even 
durability. Amazing we have so many of them still about. The reason they 
survive is old closets and attics and people like you.

-- 
Mark L. Bardenwerper, Sr.

Technology...thoughtfully, responsibly.

Visit me at http://citroen.cappyfabrics.com