Re: EDD Sound Quality
Posted: Tue Jun 17, 2025 5:13 pm
Edison patented the use of stearin to preserve the surface of diamond discs, see attached. Its shortage was reported at the WWI period.
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This was something I was aware, but not that it was patented. Possibly a thin waxy polish applied to the discs would have needed very little raw material per record compared with the varnish and powder blank.
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So, diamond discs were just discs of china clay coated in resin coated in stearin?