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upPresto 8N Disc Cutting Lathe (1950) used by the Canadian Broadcasting Corporation to record radio programs
A disc cutting lathe is a device used to transfer an audio signal to the modulated spiral groove of a blank master disc for the production of
Prior to the success of Western Electric's "Westrex" system, master discs were produced acoustically and without electricity. In 1921, John J. Scully, a former Columbia Phonograph Company employee, designed and built a weight-driven lathe specifically designed for use by phonograph manufacturers. The first Scully lathe was sold to Cameo Records. John's son, Lawrence, founded Scully Recording Instruments.
In 1924, 
In 1947, the Presto 1D, Fairchild 542, and Cook feedback cutters represented major improvements in disc-cutting technology. In 1950 Scully Recording Instruments introduced a disc cutting lathe with variable pitch, which made it possible to vary the width of the grooves (i.e. the pitch) of a master disc, simultaneously conserving the available recording space of the disc while preserving the dynamics and fidelity of the recorded material. Five years later, the company introduced automation for this variable pitch feature.
In 1957, Westrex demonstrated the first commercial "45/45" stereo cutter head.
In 1966, Neumann introduced the VMS66, followed by the VMS70 (1970) and the VMS80 (1980), which introduced variable pitch to Neumann's offerings, reducing speed fluctuations to achieve smoother sound and extended dynamic range. Unlike other systems, Neumann's disc cutting system was complete and included the lathe, cutter head, and electronics.
Audio Record Magazine: Quick Facts On Disc Recorders (October 1952)
Sound recording technology
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phonograph records
A phonograph record (also known as a gramophone record, especially in British English), or simply a record, is an analog sound storage medium in the form of a flat disc with an inscribed, modulated spiral groove. The groove usually starts nea ...
. Disc cutting lathes were also used to produce broadcast transcription discs and for direct-to-disc recording.
Overview
Disc cutting lathes utilize anaudio signal
An audio signal is a representation of sound, typically using either a changing level of electrical voltage for analog signals, or a series of binary numbers for digital signals. Audio signals have frequencies in the audio frequency range of ro ...
, sent through a cutting amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It may increase the power significantly, or its main effect may be to boost t ...
to the cutter head, which controls the cutting stylus
A stylus (plural styli or styluses) is a writing utensil or a small tool for some other form of marking or shaping, for example, in pottery. It can also be a computer accessory that is used to assist in navigating or providing more precision ...
. The cutting stylus engraves a modulated spiral groove corresponding to the audio signal into the lacquer
Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity.
Asian lacquerware, which may be c ...
coating of the master disc. The direct metal mastering (DMM) process uses a copper-coated rather than lacquer-coated disc. Before lacquer discs, master recordings were cut into blank wax discs.
Once complete, this master disc is used to produce matrices from which the record is pressed. For all intents and purposes, the finished record is a facsimile of this master disc.
History
Prior to the success of Western Electric's "Westrex" system, master discs were produced acoustically and without electricity. In 1921, John J. Scully, a former Columbia Phonograph Company employee, designed and built a weight-driven lathe specifically designed for use by phonograph manufacturers. The first Scully lathe was sold to Cameo Records. John's son, Lawrence, founded Scully Recording Instruments.
In 1924, Western Electric
The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment ma ...
purchased a Scully weight-driven lathe to demonstrate their "Westrex" cutter head and electronics for both the Columbia Phonograph Company and Victor Talking Machine Company
The Victor Talking Machine Company was an American recording company and phonograph manufacturer that operated independently from 1901 until 1929, when it was acquired by the Radio Corporation of America and subsequently operated as a subsidi ...
. Both companies began using the Westrex system for recording sessions in 1925 after agreeing to license the system from Western Electric.
In 1931, German manufacturer Georg Neumann & Co. introduced the AM31 disc-cutting lathe, which employed a direct-drive design. Two years later, Neumann introduced a portable lathe capable of making recordings on location. Imports of Neumann lathes into the United States were restricted, however, and Neumann lathes were not imported to the United States until the 1960s. Scully dominated the U.S. marketplace for professional recording lathes from the 1930s to the 1960s, and almost all American lacquer masters were cut using a Scully lathe, often fitted with the Westrex cutter head and electronics.
In 1947, the Presto 1D, Fairchild 542, and Cook feedback cutters represented major improvements in disc-cutting technology. In 1950 Scully Recording Instruments introduced a disc cutting lathe with variable pitch, which made it possible to vary the width of the grooves (i.e. the pitch) of a master disc, simultaneously conserving the available recording space of the disc while preserving the dynamics and fidelity of the recorded material. Five years later, the company introduced automation for this variable pitch feature.
In 1957, Westrex demonstrated the first commercial "45/45" stereo cutter head.
In 1966, Neumann introduced the VMS66, followed by the VMS70 (1970) and the VMS80 (1980), which introduced variable pitch to Neumann's offerings, reducing speed fluctuations to achieve smoother sound and extended dynamic range. Unlike other systems, Neumann's disc cutting system was complete and included the lathe, cutter head, and electronics.
References
{{ReflistExternal links
Audio Record Magazine: Quick Facts On Disc Recorders (October 1952)
Sound recording technology