SONY TA-8650

Commentary

The first pre-main amplifier using V-FET to realize faithful waveform transmission.
We developed dozens of new devices such as V-FET and modularized DC unit amplifiers, and put all of them into the amplifier. It was the first model in the ES-II series, an extension of the previous ES series.

The V-FET is a Sony-developed device that has excellent pulse response characteristics, smooth pinch-off characteristics, high input impedance and low output impedance characteristics, N-channel and P-channel complimentary service characteristics, and voltage response characteristics. The V-FET has excellent high-frequency characteristics and low crossover distortion and notching distortion.

The A-class stage of the power amplifier is a 3-stage differential amplifier with dual FET in the first stage, and a pure complimentary service triple push-pull configuration with V-FET in the output stage.

The equalizer stage employs a DC unit amplifier (BX-269) capable of transmitting waveforms and an IC amplifier.
The BX 269 is a modular version of the first stage FET differential amplifier and other circuits. It achieves flat frequency characteristics from DC to MHz order and excellent phase characteristics.

The Phono1 is for general use, and the Phono2 is for Low, High and MC-type head amplifiers with three positions.
A direct coupling method is used for input of the cartridge.
The head amplifier uses a low-noise LEC transistor, which is very useful for MC-type low-impedance signal sources.

A high-voltage low-noise IC is used in the microphone amplifier to respond to all commercially available microphones and operating conditions.

A DC unit amplifier (BX-270) is used as a buffer amplifier, and low / high filters with sharp cut-off characteristics are mounted.

It is equipped with an acoustic compensator that corrects the sound field and can be switched between 5 positions.
In addition, it is equipped with a muting switch and a tone control capable of switching the turnover frequency.

It has a preset volume.

It is equipped with a clip level indicator that warns of the clip point of input level (microphone or phono) and output level by LED (light emitting diode) with excellent response speed.

Equipped with an extra adapter terminal that can be connected to a 4-channel adapter, an octave equalizer, and a third deck.

It uses an electrolytic capacitor for ± 2 power with two capacitor elements enclosed in one pack.

Equipped with a chimney type heat sink that is forced to air-cool by installing a duct.

Model Rating

Type	Stereo pre-main amplifier
Effective output (both channel operation)	1 kHz : 90W + 90W (8 Ω) 20 Hz to 20 kHz : 80W + 80W (8 Ω)
Harmonic distortion factor	0.1% or Less (Effective Output)
Cross modulation distortion factor	0.1% or Less (Effective Output)
Damping factor (1 kHz, 8 Ω)	200 or higher
Phono maximum allowable input (1 kHz)	175 mv, 310 mv
Tone control (Turnover frequency in parentheses)	Bass (250 Hz) : 50 Hz + / - 10 dB (500 Hz) : 100 Hz + / - 10 dB Treble (5 kHz) : 20 kHz ± 10 dB (2.5 kHz) : 10 kHz ± 10 dB
Filter	Low : 10Hz/40Hz or less, 12dB/oct. High : 9kHz/20kHz or more, 12dB/oct.
Acoustic Compensator	Low1, 2, presence, loudness
Power consumption	240W
External dimensions	Width 440x Height 170x Depth 425 mm
Weight	20.8kg