1976 - 1977. $170 in 1972 (JC1-AC). JC1 DC is battery operated (2 x 1.5 D size cells).
The name JC may come from the John Curl, one of the enginner of MLAS.
Technical details : someone said on USENET «In my opinion, the JC-1 combines the best of both world, active-gain pre-preamp and passive step-up transformer.» (so NO RIAA correction).
«Has 2 RCA jacks in & out. Powered by 9-Volt battery, unit measures approx. 7Wx1Hx4D inches. Tested 1.5db down @ 20Khz and 3db down @ 20Hz».
The design of this preamplifier is pattentd, see US4035737: Low noise amplifier. Here is the abstract :
A low noise amplifier for amplifying a signal from a moving coil phono cartridge which comprises a plurality of pairs of complimentary first and second transistors in push-pull and each pair in parallel, with a resistance of relatively low-value in the emitter circuit of each transistor and all collectors connected to an output terminal.
The schematics & description are included in the patent.