Ortofon 100U (ca. 1985)

Little is documented about the Ortofon MC 100U outside one period publication. The August 1985 issue of HiFI-Stereo carried a lab test of the "ORTOFON MC 100U CARTRIDGE," flagged on its cover among the equipment tested (August 1985, p.1, p.39-40). The February 1986 issue listed the model again in its cartridge directory (February 1986, p.117). Those two appearances are nearly the entire surviving record.

The 100U was a low-mass moving-coil phono cartridge with a wide-range damping system and a nude elliptical diamond stylus (HiFI-Stereo, February 1986, p.117). The directory listing specifies output of 0.09 mV, frequency response of 20-20,000 Hz +3/−1 dB, and channel separation of 25 dB at 1 kHz (HiFI-Stereo, February 1986, p.117). In the lab test, the reviewer measured a slightly higher output of roughly 0.12 mV - the figure reached through a 40-to-1 step-up transformer with channel levels matched within 0.25 dB. The difference from the published spec is likely just measurement conditions (HiFI-Stereo, August 1985, p.40). The same review noted a real quirk: when the loading was adjusted to flatten the frequency response, phase shift extended down into the audio band and stereo imaging degraded (HiFI-Stereo, August 1985, p.39).

No production years, original price, or service documentation have surfaced in the Archive's research, and the directory's tracking-force figure is truncated in the surviving scan. The period record does establish that Ortofon offered the MC 100U as a low-output MC design with a serious damping system, and that it got a full lab report in 1985.

Known specs from the period record: