SONY TA-F6B
¥ 99,800 (released in 1977)
Commentary
A DC pre-main amplifier developed and equipped with a pulse lock power supply utilizing electronic circuit technology in order to realize a superior power supply unit.
The pulse power supply directly rectifies 100 VAC, converts this DC into a 20 kHz pulse, transforms it with a ferrite core transformer, and converts it into a DC voltage again. It is highly efficient and has very few ripple components.
In addition, the TA-F6B is equipped with a feedback circuit of pulse width control method to aim at constant voltage, and voltage fluctuation rate of 1% or less from 0W to 100W output has been realized. This suppresses the linearity deterioration of the amplifier section. Moreover, since there is no low-frequency magnetic leakage, hum does not come out even with a small input such as MC cartridge, and high SN is obtained.
In addition, in combination with the FET buffer power supply, voltage distribution from the power section to the pre-section is reduced.
The first stage of the MC head amplifier has a low-noise LEC transistor connected in parallel to reduce the equivalent noise resistance, and the second stage has a two stage direct connection structure with a Darlington connection.
It is equipped with an equalizer amplifier of current mirror differential amplification configuration using dual FET, and low-frequency transmission characteristics are improved by direct coupling.
In addition to the NF circuit that produces the RIAA playback curve, a DC feedback circuit using an FET is also employed to stabilize the operating point and eliminate the large capacitor of the NF circuit, thereby improving sound quality.
The power amplifier uses a source follower circuit with dual FET at the first stage, monolithic ICs at the driver stage, and a pure complimentary service SEPPP OTL circuit at the last stage.
It uses a DC amplifier configuration that does not shift the phase of the low frequency range.
Self-defeat tone control is adopted, and low-noise, high-voltage monolithic IC is adopted for the tone amplifier.
A 4-row detent volume is used.
Construction is adopted to minimize the wiring from the input to the output and reduce the interference of the signal system due to stray capacity.
Gold plated Phono terminal is used.
.JPG)
Model Rating
| Type | Pre-main amplifier |
| Effective output (20 Hz to 20 kHz, both channels) | 100W + 100W (8 Ω) |
| Output Bandwidth (IHF, 8 ω) | 5 Hz to 35 kHz |
| Harmonic distortion factor | 0.03% (20 Hz to 20 kHz, Effective Output) |
| Cross modulation distortion factor (at effective output) | 0.01% |
| Damping factor (1 kHz, 8 Ω) | 50 |
| Phono input sensitivity | 2.5mV |
| Phono maximum allowable input (1 kHz) | 250mV |
| Tone control | Bass : 60 Hz ± 10 dB Treble : 25 kHz ± 10 dB |
| Filter | Low : 6dB/oct. (15 Hz or less) High : 6dB/oct. (9 kHz or higher) |
| Power consumption | 190W |
| External dimensions | Width 430x Height 170x Depth 390 mm |
| Weight | 12kg |