The ORTOFON S 15 was designed in the '60s and was based on the ORTOFON SPU.
A peculiar thing was the S 15-T version with an integral transformer.
Specifications:
Frequency response: 15 to 40,000Hz
Impedance: 15k ohms
Stylus pressure: 1 to 2g
Channel separation: 20 to 30dB
