SONY TA-F555ES

Commentary

This pre-main amplifier is based on our proprietary technology and has been designed to support digital sources with thorough low brush-up of details.

It employs an audio current transfer method that eliminates interference between the four amplifiers.
In this circuit, the signal applied to the preamplifier is converted into a constant current type signal system using a current conversion amplifier, and the voltage signal is taken out again using a 2-terminal linear gain control attenuator at the first stage of the power amplifier as a load.
As a result, the preamplifier has infinite impedance as seen from the power amplifier and is completely electrically disconnected. At the same time, the L/R channels are separated so that the characteristics of the preamplifier, power amplifier and L/R channel can be pursued independently, and ideal grounding is possible. The input signal and load are clearly defined, there is no influence of the ground loop or power source impedance, and disturbance caused by wires or switches in the signal path can be ignored.

The volume is equipped with a 2-terminal linear gain control attenuator. This attenuator has characteristics such that the impedance decreases as the gain decreases and the acoustic characteristics become better. Therefore, the characteristics in actual use become better.

A constant-current shunt regulator is used in the power supply section of the preamplifier to completely eliminate the influence of the power amplifier power supply and to reduce the source impedance to almost 0, ensuring stable regulation.

Legato linear system is used for power amplifier section.
This technology drastically reduces switching and crossover distortion without changing bias or power supply voltage. It has such features as "no nonlinear elements added to the signal system", "operating conditions do not change depending on the magnitude of the input signal", "no switching distortion is observed up to the ultra-high frequency band of 100 kHz", and "stable operation including phase characteristics is guaranteed".
As a result, high-speed and wide-band characteristics are realized, and high frequency distortion and good phase characteristics are obtained.

A DC servo is used in all amplifier sections of the equalizer, current drive and power amplifier.
In addition, in order to eliminate thermal modulation distortion of circuits and elements, a constant PC circuit is adopted in the differential section of the equalizer amplifier and the first stage of the power amplifier. In addition, a dedicated heat sink is installed in each element to improve resolution in the audible band.

We put in high-quality parts that have undergone repeated hearing tests.
The power transistor is compatible with a Hi-ft transistor. This Tor G-ster has a wide-band operating range of 60 MHz to 80 MHz, which is more than one order of magnitude higher than the conventional 4 MHz, so that the high-frequency response characteristics are remarkably improved.
In addition, it uses a large-capacity capacitor, high-speed rectifier diode, oxygen-free copper internal wiring material and power cord, copper-plated copper-tight case to reduce magnetic strain, etc.

MM cartridge and MC cartridge can be connected.
In addition, it is equipped with MC (40 Ω / 3 Ω) and MM (330pF/100pF) cartridge load selectors.

Equipped with a Rec out selector that allows you to select the recording source regardless of the listening source and to copy it from Tape1 to Tape2.

It has a tone control circuit and a direct switch that passes through the circuit.

Equipped with a base boost function.

Equipped with a muting circuit.

Built-in speaker protection circuit.

Model Rating

Type	Pre-main amplifier
Circuit system	Current drive integrated stereo amplifier Addition of low-noise Hi-GAIN co-riser amplifier and DC servo Addition of bridge balanced current conversion amplifier and DC servo Legato linear, all stages directly connected pure complimentary service Triple Darlington SEPP Power Amplifier DC Servo Addition
Effective power	100W + 100W (20 Hz to 20 kHz, both channel operation, rated harmonic distortion rate, 8 to 16 Ω load) 100W + 100W (at 4 Ω ~ 6 Ω load)
Output bandwidth	5 Hz to 100 kHz (50W output, 0.02% harmonic distortion rate, 8 Ω) 5 Hz ~ 80 kHz (4 Ω)
Harmonic distortion factor	0.004% or Less (20 Hz to 20 kHz, 8 Ω at Rated Output) 0.01% (4 Ω at rated output)
Cross modulation distortion factor	0.004% or Less (8 Ω at Rated Output, 60 Hz : 7 khz = 4 : 1) 0.01% (4 Ω at rated output)
Slew rate	100 V / μ sec 250 V / μ sec (inside)
Damping factor	125 (1 kHz, 8 Ω)
Frequency characteristic	Phono : RIAA curve ± 0.2 dB Tuner/Aux/Tape/CD : 2 hz to 200 khz + 0 to 3 db
Signal-to-noise ratio	Phono MM:87dB Phono MC:70dB Tuner/Aux/Tape/CD:97dB
Input sensitivity / Impedance	Phono MM : 2.5mV/100pF, 330pF/50k Ω Phono MC (40 Ω) : 130 μ V/100 Ω Phono MC (3 Ω) : 130 μ V/30 Ω Tuner/Aux/Tape/CD : 150mV/50k Ω
Output level / Impedance	Rec out : 150mV/1k Ω Speaker : 4 Ω ~ 16 Ω Headphone : 30mW/8 ohm
Tone control	Bass : ± 8 dB (60 Hz, turnover frequency 300 Hz) Treble : ± 8 dB (25 kHz, 5 kHz turnover frequency)
Subsonic filter	15 Hz or less, 6dB/oct.
Base boost	+4dB(50Hz)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	193W
External dimensions	Width 430x Height 130x Depth 367 mm
Weight	13kg