SONY TA-FA7ES

Commentary

This pre-main amplifier was announced as the flagship model of the New ES series.

A twin-monaural construction is adopted in which the power supply is placed in the center of the chassis and left and right power amplifiers are placed on both sides of it.
Good channel separation is achieved by separating the power amplifier, which tends to cause crosstalk between channels, like a monaural amplifier in which the heat sink is independent on the left and right.

For the pre-section that handles small signals, we have adopted a 2-box separation structure that separates the inside of the chassis with beams in consideration of the influence of the power section and power section with large current.

The amplifier circuit begins with a junction FET that eliminates the need for a coupling capacitor at the input stage, and extends to a MOS FET at the voltage amplifier stage (A-class stage), drive stage, and power MOS FET at the final stage, all of which use non-magnetic FETs exclusively for audio.
MOS FET's high input impedance allows the driver stage and output stage to be electrically separated, reducing interference with each other. As a result, high sound quality can be obtained with a relatively simple circuit structure, and odd order distortion, which is easy to be heard, can be suppressed.

To take advantage of the superior characteristics of MOS FET, the new ES amplifier uses MOS-exclusive design.
This circuit is called an optical bias circuit in which an optical element having the same temperature characteristics as the MOS FET is added to the bias circuit in order to suppress the variation of the idling current that occurs when the temperature characteristics of the bias circuit and the temperature characteristics of the MOS FET of the current amplification stage do not match. This circuit is called an optical bias circuit in which an optical element having the same temperature characteristics as the MOS FET is added to the bias circuit, so that the idling current is kept constant and the audio signal is amplified more stably.
In addition, by increasing the capacity of the bypass capacitor of the bias circuit and reducing the impedance, a rich low-frequency range is obtained.

We have adopted a newly developed torus toroidal transformer for the transformer of the power supply section. In this transformer, the core section of the conventional toroidal transformer is made into an oval shape to improve the adhesion of the coil. This improves efficiency, greatly reduces vibration, and reduces the influence on the audio signal. In addition, since the total length of the coil is shortened, impedance is lowered.

Advanced S. T. D. (Spontaneous Twin Drive) power supply is used for the power supply part.
In the conventional S. T. D. power supply, the voltage amplifier stage (A class stage) and the power amplifier stage (B class stage) are separately and independently supplied with power from the rectifier circuit. Thus, the change in the power supply voltage of the power amplifier stage does not adversely affect the power supply of the voltage amplifier stage even at high output, and the sound quality is improved.
The Advanced S. T. D. power supply is a further development of this system. An induction coil is added to the voltage amplification stage to reduce voltage fluctuations during rectification. A large-capacity capacitor is also equipped to supply a large instantaneous current, thereby improving sound quality in the middle and high frequency range, S / N ratio and dynamic range.

The newly adopted pure input circuit reduces the number of switches on the signal path from the input terminal through the input selector to the master volume to less than half of the conventional switches, thereby reducing signal degradation. For the same reason, the muting circuit is also designed without contact points on the signal path.
In addition, all signals from each input terminal were sent to the Rec out selector until now. However, by releasing circuits other than the source selected by the Rec out selector right after the input terminal, the purity of the signal is kept higher.

The TA-FA7ES is equipped with an XLR-type balanced input that can cancel noise components in the transmission system by transmitting both positive and negative audio signals simultaneously.
In addition, a metal core module is used for the balance input circuit. This circuit board is made of a metal core (metal substrate) made of an aluminum alloy with excellent thermal conductivity. After heat-resistant insulation treatment is applied, copper circuit patterns are formed, and components are surface-mounted on the metal core. This eliminates the lead wires of components and reduces contact points, thereby maintaining the purity of signals through balance transmission.

A large aluminum heat sink for each of the left and right channels is installed to maintain a balance between the temperature inside the chassis and to obtain good separation characteristics.
In the TA-FA7ES, the heat sink is treated with fluorine to suppress the resonance of the heat sink itself, thereby reducing vibration generated from inside the chassis.

The FB chassis is made of metal with sufficient strength and thickness. The entire chassis is constructed as a solid box. In addition, the frame surrounding the outer circumference and the beams passed in front, back, left and right have different shapes and sizes and are combined by screws. This makes the frame and beams with different vibration modes combined, greatly reducing vibration inside and outside the chassis.
In addition, the power supply and heat sink are fixed to the central base beam to ensure good weight balance and strength.

An eccentric insulator is used for the insulator. By offsetting the screw hole from the center, the phase of vibration transmitted from each direction on the circumference to the screw is changed, and vibration transmitted to the chassis is mutually cancelled. The shape was a prototype and sound quality was examined. As a result, the diameter was reduced to 50 mm, which is smaller than conventional ones.
In addition, cast iron is used for TA-FA7ES.

The volume is a high-quality volume that uses a low-distortion print resistor and a non-magnetic, gold-plated slider brush.

The output stage employs a super legato linear system that reduces switching distortion and crossover distortion, and also reduces distortion at the reproduction level in actual use.

Built-in phono equalizer amplifier with low-noise FET.

Equipped with an ES filter that reduces noise contamination from the AC line.

Pre-output terminal is mounted.

There are 2 variations, gold and black.

Wireless remote control is included.

Model Rating

Type	Pre-main amplifier
Effective output (20 Hz to 20 kHz)	120W + 120W (4 Ω) 100W + 100W (6 Ω) 80W + 80W (8 Ω)
Input Sensitivity / Impedance	Phono MM : 2.5mV/50k Ω Phono MC : 170 μ V/100 Ω Line system : 150mV/50k Ω
Output Level / Impedance	Rec out : 150mV/1k Ω Headphone : 25 mW (8 Ω)
Total harmonic distortion factor	0.008% (8 Ω at 10W output)
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1)	0.008% (8 Ω at rated output)
Frequency characteristic	Phono MM : 20 Hz to 20 kHz ± 0.2 dB Line system : 2 Hz ~ 100 kHz + 0 -3dB
Signal-to-noise ratio	Phono MM:87dB Phono MC:70dB Line system : 105 dB
Tone control	Bass : ± 7 dB (100 Hz) Treble : ± 6 dB at 10 kHz
Accessory function	Source direct switch Rec out off Rec Out Selector Remote Commander
Pwer	100 VAC, 50Hz/60Hz
Power consumption	230W
External dimensions	Width 430x Height 175x Depth 450 mm
Weight	Approx. 19.8 kg
Attachment	Wireless Remote Control RM-J350