Signal Extraction from Instantaneous Lacquer Discs Robert Cowlin

Introduction to Lacquer Discs www. bl. uk 2

Also known as… • • • Laminate disc Transcription disc Instantaneous disc "Acetate" disc Direct-cut disc. www. bl. uk 3

Format Characteristics (c. 1940) • Frequency response: 50 Hz – 8 k. Hz (dictated by cutting head) • Signal-to-noise ratio: >50 d. B • Sizes: 5”, 7”, 10”, 12”, 13”, 14”, 15”, 16”. www. bl. uk 4

Emelie Hooke lacquer disc collection www. bl. uk 5

Transfer Workflow www. bl. uk 6

Preparation www. bl. uk 7

Cleaning www. bl. uk 8

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Before and After… www. bl. uk 11

Choosing the Stylus www. bl. uk 12

Jim Lesurf, Hi-Fi News www. bl. uk 13

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Coarse groove styli www. bl. uk 17

Selecting a stylus without wearing out the disc… www. bl. uk 18

Equalisation Peter Copland, Manual of Analogue Audio Restoration Techniques www. bl. uk 19

Final preparation www. bl. uk 20

Capture www. bl. uk 21

Playback www. bl. uk 22

Further reading • Beardsley, R. and Leech-Wilkinson, D. (2009). A Brief History of Recording to ca. 1950. www. charm. rhul. ac. uk/history/p 20_4_1. html • Copeland, Peter. Manual of Analogue Audio Restoration Techniques. The British Library. • Fantel, Hans. “Fabulous Phono Cartridges: 4 Channels and 50, 000 Hz”. Popular Mechanics, April, 1975. • Guidelines on the Production and Preservation of Digital Audio Objects. www. iasa-web. org/tc 04/audio-preservation • Lesurf, J. (2007). Around the Bend. www. audiomisc. co. uk/HFN/LP 3/aroundthebend. html • Phonograph Pickup Stylus. US 3774918 A. Victor Company of Japan, Ltd. , 1973. • Presto Instantaneous Sound Recording Equipment and Discs. New York: Presto Recording Corporation, 1940. • Street, Sean. Historical Dictionary of British Radio. Lanham: Rowman & Littlefield, 2015. www. bl. uk 23

Thank you Robert. Cowlin@bl. uk @cowlin_robert www. bl. uk 24