Ortofon SL-15 (c. 1967–1971)
The Ortofon SL-15 is a moving-coil phono cartridge from Ortofon of Denmark, first announced in 1967. Ortofon's own advertising in Audio (September 1967, p.55) called it the "no compromise" cartridge "with Ortofon performance for automatic turntables". That's an unusual pitch for a high-end moving-coil design of the period. Exact production dates aren't documented, but period reviews run from 1967 through 1971.
The cartridge came in a couple of forms: the SL-15 itself, and an SL-15T variant. The SL-15T is a stereo phono cartridge with an elliptical stylus (0.7 by 0.3 mil). High Fidelity (November 1967, p.73) tested it alongside Ortofon's RS 212 tonearm and noted that CBS Lab tests confirmed the Ortofon's performance. HiFi/Stereo (July 1968, p.64) published measured frequency-response curves for the SL-15. A later High Fidelity piece (February 1971, p.46) described a redesigned internal four-magnetic-gap generator, claimed to extend high-end response without resonances or peaking.
The SL-15 is a moving-coil design, so its output is low. High Fidelity (July 1971, p.47) reported that Ortofon had long been established internationally as one of the very best phono pickups. The company dealt with the low output through a "little black box": the MP 235, a solid-state preamp built by Martin Electronics of Kansas City and distributed by Elpa Marketing Industries. List prices at the time were $90 for the SL-15 cartridge alone, $75 for the MP 235 preamp alone, and $150 for the SL-15/MP 235 combination.
Beyond those reviews, the archive's own files on the SL-15 are thin. The period record does place it among Ortofon's higher-end cartridges of the late Sixties and early Seventies.
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