[78-L] playing vertical disc from metal part

Doug Pomeroy audiofixer at verizon.net
Mon Apr 30 03:38:18 PDT 2012

Hi Jerry,

Well said, and what I would have expected - geometry definitely
different.  Maybe Expert Stylus Company would be wiling to design
something suitable?  I once sent them an RCA Home Recording disc
to have them make a proper stylus for playing it, which they did (5.0  

Keeping on keeping on.

Regards to Thomas!


> Message: 18
> Date: Mon, 30 Apr 2012 14:04:09 -0400
> From: Gerald_Fabris at nps.gov
> Subject: Re: [78-L] playing vertical disc from metal part
> To: 78-l at klickitat.78online.com
> Message-ID:
> 	<OFB1F9158A.263AAE73-ON852579F0.006035D1-852579F0.006341C4 at nps.gov>
> Content-Type: text/plain; charset=US-ASCII
> On 04/27/2012 12:44 PM, neechevoneeznayou at gmail.com wrote:
>> Is it possible to play a metal part to a vertical record with a
>> bifurcated stylus?
> I've done some test transfers of negative metal Edison Diamond Discs.
> Edison used the term "mold" for negative metal parts, using disc  
> molds in 3
> stages: "Master Mold", "Second Master Mold", and Working Mold".
> Yes, it is possible to play a Diamond Disc mold using a bifurcated  
> stylus.
> I've had some good results.  I had 3 sizes lent to me for testing,  
> and 2
> sounded wrong, but one sounded very good.
> BUT, bifurcated styli are designed for lateral grooves.  As far as I  
> know,
> no one has ever made a bifurcated stylus designed specifically for a
> negative vertical groove.  With a vertical groove, a stylus must  
> ride along
> an ever-changing groove width and depth.  With lateral, the groove is
> basically a constant width and depth.  So, the geometry is more  
> complex for
> vertical.
> Jerry Fabris, Museum Curator
> Thomas Edison National Historical Park
> National Park Service
> United States Department of the Interior
> 211 Main Street
> West Orange, New Jersey 07052
> tel:  (973) 736-0550, ext. 48
> fax: (973) 243-7172

Doug Pomeroy
Audio Restoration & Mastering Services
Transfers of metal parts, lacquers,
shellac and vinyl discs & tapes.
193 Baltic St
Brooklyn, NY 11201-6173
(718) 855-2650
audiofixer at verizon.net

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