Sony - TA-F55 - ST-J55L MM-MC phono Solid state integrated amplifier

High quality hifi setup from the early 80ties. Cool motorized volume scale, very special design.
All contacts are cleaned.
Very good powerful sound due pulse power supply and discrete power amp (no STK!)
Volume buttons detect soft or hard press, for slow or fast control.
The amp has a good phono input for MM and MC!
All lamps work!
On the back are several RCAs connectors. Phono input is gold plated.
Cables included.

The tuner is also 100%, also stereo on a short wire.
Programmable FM presets.

Amp spec’s:

Power output: 70 watts per channel into 8Ω (stereo)

Frequency response: 5Hz to 70kHz

Total harmonic distortion: 0.008%

Damping factor: 50

Input sensitivity: 0.17mV (MC), 2.5mV (MM), 150mV (line)

Signal to noise ratio: 75dB (MC), 90dB (MM), 104dB (line)

Output: 150mV (line)

Dimensions: 430 x 80 x 320mm

Weight: 4.6kg

Pictures are part of the description.

Carefully shipped

By 1979, Sony amplifiers had abandoned their exotic but unreliable V-FET output transistors, and were innovating in different ways – the challenge was to add an interesting twist to a conventional design. So from the middle of the new TA-F range upwards, Sony engineers placed the power transistors on the main circuit board in order to get ultra short signal paths. Normally that would result in the board melting, so rival manufacturers had never dreamed of doing it – but Sony thought otherwise. It came up with a novel ‘heat pipe’ filled with freon gas, that transferred heat away to multiple thin cooling fins, further away from the amplifier’s power transistors. It was pretty zany stuff, especially by the standards of the day.

The TA-F55 delivered excellent measured performance, making a claimed 70W RMS per channel into 8 ohms – this was a lot of power for a full sized high end amplifier of that time, let alone a half-height one. Its damping factor was quoted at 50, and the THD figure was an extremely low 0.08%. The amplifier had a choice of moving coil and moving magnet phono inputs, with sensitivities of 0.25mV and 2.5mV respectively and two-step capacitance and impedance switching via small front panel selectors. There were also tuner, auxiliary and twin tape monitor circuits. Bass and treble controls were fitted, giving 10dB of boost or cut at 100Hz and 5kHz, in traditional Sony style. A -20dB muting switch was fitted too, and two sets of speaker outputs which sadly only accept relatively slim bare wire cables.

Definitely a piece.of collectable history.