Editing Phonograph (section)

== Stylus ==
[[File:RedDevilNeedle.jpg|thumb|left|Stylus for [[jukebox]] using [[shellac]] 78 rpm records, 1940s]]

A development in stylus form came about by the attention to the [[Compatible Discrete 4|CD-4]] [[quadraphonic]] sound modulation process, which requires up to 50&nbsp;kHz frequency response, with cartridges like [[Technics (brand)|Technics]] EPC-100CMK4 capable of playback on frequencies up to 100&nbsp;kHz. This requires a stylus with a narrow side radius, such as {{convert|5|μm|mil|sigfig=1|link=out}}. A narrow-profile elliptical stylus is able to read the higher frequencies (greater than 20&nbsp;kHz), but at an increased wear, since the contact surface is narrower. For overcoming this problem, the '''Shibata stylus''' was invented around 1972 in Japan by Norio Shibata of JVC.<ref>US Patent 3774918</ref>

The Shibata-designed stylus offers a greater contact surface with the groove, which in turn means less pressure over the vinyl surface and thus less wear. A positive side effect is that the greater contact surface also means the stylus reads sections of the vinyl that were not worn by the common spherical stylus. In a demonstration by JVC records worn after 500 plays at a relatively high 4.5&nbsp;g tracking force with a spherical stylus, played perfectly with the Shibata profile.<ref>{{cite web |url=http://www.johana.com/~johana/dorren/cd-4paper4.pdf |title=Johana.com |access-date=2011-10-12 |url-status=dead |archive-url=https://web.archive.org/web/20110713112415/http://www.johana.com/~johana/dorren/cd-4paper4.pdf |archive-date=2011-07-13 }}</ref>

Other advanced stylus shapes appeared following the same goal of increasing contact surface, improving on the Shibata. Chronologically: "Hughes" Shibata variant (1975),<ref>US Patent 3871664</ref> "Ogura" (1978),<ref>US Pat. 4105212</ref> Van den Hul (1982).<ref>US Pat. 4365325</ref> Such a stylus may be marketed as "Hyperelliptical" (Shure), "Alliptic", "Fine Line" (Ortofon), "Line contact" (Audio Technica), "Polyhedron", "LAC", or "Stereohedron" (Stanton).<ref name="vinylengine.com">{{cite web |url=http://www.vinylengine.com/phpBB2/viewtopic.php?t=22894&start=0 |title=Vinylengine.com |publisher=Vinylengine.com |date=2009-11-09 |access-date=2011-10-12 |url-status=live |archive-url=https://web.archive.org/web/20110717210500/http://www.vinylengine.com/phpBB2/viewtopic.php?t=22894&start=0 |archive-date=2011-07-17 }}</ref>

A keel-shaped diamond stylus appeared as a byproduct of the invention of the [[Capacitance Electronic Disc|CED Videodisc]]. This, together with laser-diamond-cutting technologies, made possible the "ridge" shaped stylus, such as the Namiki (1985)<ref>US Patent 4521877</ref> design, and Fritz Gyger (1989)<ref>US Patent 4855989</ref> design. This type of stylus is marketed as "MicroLine" (Audio technica), "Micro-Ridge" (Shure), or "Replicant" (Ortofon).<ref name="vinylengine.com"/>

To address the problem of steel needle wear upon [[Phonograph record|records]], which resulted in the cracking of the latter, [[RCA Victor]] devised unbreakable records in 1930, by mixing polyvinyl chloride with plasticisers, in a proprietary formula they called Victrolac, which was first used in 1931, in motion picture discs.<ref>Barton, F.C. (1932 [1931]). ''Victrolac Motion Picture Records''. Journal of the Society of Motion Picture Engineers, April 1932 '''18'''(4):452–460 (accessed at archive.org on 5 August 2011)</ref>