Solid, very solid chunk of mid 1970s silver, at first made for the earlier SU-8600, then, later on, under brown-ish black looks and ST-9600 name to serve as mid-end tuner for the 96xx and 97xx series but for the export market only...
Not only Sony made strange moves !
Flat group delay ceramic filters, PLL MPX, 8-gang capacitor (5 for FM, 3 for AM), 4-pole Mos-Fet RF amp, two-step muting ("deep") and direct FM-to-tape recording.
FM-to-tape means that the play/rec tape terminals are on the ST-8600 to bypass the amplifier loop ; the pre-emphasized broadcast signal is recorded and played back through the tuner's de-emphasis circuit to recover the original flat response.
Added for 1974 frills : a 4-channel MPX output.
Added for the serious tuner-phile : an FM multipath output.
Excellent industrial design wich Technics sadly dropped earlier than most others, before 1978, swapping the warm wood for optional rack adaptors and heavy metal.
Be sure to read the FMtunerinfo review of both ST-8600 and ST-9600 !