RE: arsclist Transfer of multiple copies, was: Full 3-D mapping o f groove?

["George Brock-Nannestad" <pattac@xxxxxxxx>]

From: Patent Tactics, George Brock-Nannestad

Peter Copeland wrote (ever so much more interesting than 
cataloguing!)

 Using a parallel-tracking pickup
> with its vertical pivots located in the plane of the disc surface (I
> don't know a way of *buying* this mechanism, I had to adapt one), the
> synchronism was outside the capability of the CEDAR azimuth corrector,
> which fails when the synchronism exceeds 99 samples. This seemed to be
> due to minute disc warpages pushing the pickup up and down, which
> (because it had a cantilever) became translated into motion *along*
> the groove.

----- The problem is that the pull of the groove on the stylus creates 
a pull on the cantilever which is at an angle with the tonearm. The 
pull must go in the direction of the cantilever at all times, which 
actually means that the vertical pivots have to be quite a way above 
the plane of the disc surface. That way, only the possible 
lengthwise resilience of the cantilever bearing (an elastomer, but 
some pickups have a tie wire) will yield to the pulls on the stylus. 
Damping, such as obtained by having a small brush fitted to the 
cartridge on either side of the stylus will take care of minute disc 
warpages. These could be among the means you would use to 
fudge the problem.

Kind regards,


George
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