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Stamper Player

Posted: 01 Dec 2016, 18:02
by Fonotec
A stamper is made from either the nickel master or its "son". The nickel master is electrodeposited onto the silver-coated surface of the oversized lacquer disk (record). The son is electrodepopsited onto the passivated surface of the nickel mother which was electrodeposited onto the passivated surface of the nickel master. (Passivation precludes "-plating," so the new part can be separated, easily, from the mandrel.) On each part made during the stamper electroforming process, the groove profile becomes inverted from its previous state - positive grooves make negative grooves (which are elevated); negative ones make positive ones.

Since the pressing stamper is made out of one of the nickel records that bears a negative impression of the grooves of the pressed record, it can't be played on a standard record player. But it can be played on one that is designed as the mirror-image of a standard player - a stamper player. It must revolve the platter counter-clockwise (as seen from above), and the tonearm must be able to rest the stylus on the "wrong" side of the record, with the cartridge having a mirror-image of the standard headshell offset. Also, the stylus must have a bifurcated tip so that it can straddle the elevated fill of the positive record groove. Such a stylus can be made from two, conical styli that are bonded together, after a "flat" is given to both, with an identical facet along the side of each cone. This was patented* by Pickering & Company from an invention by Fairchild engineer, George Alexandrovich, Sr.)
Stanton_stamper_player_Aa.JPG (113.59 KiB) Viewed 2826 times

*Playback stylus for phonograph record stamper
US4113266-1.JPG (43.03 KiB) Viewed 2826 times

A playback stylus for a phonograph record stamper and matrix is provided. The stylus comprises a pair of substantially cylindrical jeweled members each terminating at a tipped end. The members each have a flat surface defining a plane parallel to its longitudinal axis. The members are bonded to each other along the flat surfaces with the tip ends aligned to form a [double] "V." The ends of the members opposite the tip ends are bonded to a tube.
Inventors: Alexandrovich; George (Commack, NY)
Assignee: Pickering & Company, Inc. (Plainview, NY)
Appl. No.: 05/790,391
Filed: April 25, 1977

Re: Stamper Player

Posted: 05 Jun 2018, 21:28
by Fonotec
Here's a picture of a bifurcated stylus playing the elevated groove ridge of a stamper (or a matrix), which has the exact profile in negative of the master cut.
stamper_playback.jpg (212.17 KiB) Viewed 2407 times

(image scanned from Basic Disc Mastering 2nd Edition, by Larry Boden)