Sony TA-3120
Sony TA-3120A
(1966 - 1974)

True bestseller and sllightly later addition to the original ES series from 1965, the logo of which you can see above.

The TA-3120 holds the power amplifier section of the TA-1120 (minus one smoothing capacitor) and was produced to build full-tilt active systems with the TA-4300 dedicated crossover. Centered around the TA-2000 preamp bestseller, Sony offered its loudspeakers with multiple terminals for that purpose - right from the start in 1965 !

The TA-3120 is an "all silicon transistor" stereo amplifier with quasi-complementary symmetrical circuit. Very respectable specs for the times (and still for the first half of the 1970s), built to last two or three lifetimes.
Level pots are provided at the back, along a "test" switch which acts as high pass filter at 10Hz ; the normal position cuts out at 30Hz - DC was for the next decade.
Early versions of the 3120 had a second lamp indicator for "safety", later versions didn't ; I believe the TA-3120 (1966) and TA-3120A (1967) to be basically identical. The 3120 spawned quite a few later versions, smaller or bigger : TA-3060 (1969), TA-3130F (1970), TA-3140F (1971) and probably a couple more that even I don't know about :)
None of these are as common as the later TA-3200F or the TA-2000 and TA-2000F but Sony sold plenty just the same, worldwide.

Punchy sound from the early transistorized period : a bit raw around the edges but it does kick loud.