Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!wmartin From: wmartin@brl-tgr.ARPA (Will Martin ) Newsgroups: net.audio Subject: Re: Vinyl vs. CD recordings Message-ID: <5356@brl-tgr.ARPA> Date: Wed, 17-Oct-84 09:50:14 EDT Article-I.D.: brl-tgr.5356 Posted: Wed Oct 17 09:50:14 1984 Date-Received: Thu, 18-Oct-84 19:04:58 EDT References: <3050@watcgl.UUCP> <4100001@hp-lsd.UUCP> Organization: Ballistic Research Lab Lines: 23 > A laser pickup cartridge was developed several years ago. I dimly recall > reading about it in one of the Popular*-type magazines. I wish I could > remember a reference. > > (or did they use focused LED's???) > > --Paul Bame > hplabs!hp-lsd!paul I am rather doubtful that an actual "laser" cartridge has yet been developed; however, there was a Japanese (I believe Panasonic/Matsushita) photoelectric or "light-beam" cartridge some years back. It came in a special spherical housing, like a big aluminum bubble on the end of the tonearm. I think the cantilever moved a mirror which modulated a light beam reflected on a photcell receptor of some form. The idea was to minimize the mass moved by the stylus, as usual. In any case, this (and any "laser cartridge") still is a needle-in-a-groove contact system; what I had posted a while ago about laser playback of existing vinyl discs was a postulate about a non-contact system, where only the laser light touched the disc. Will