SONY TA-AX500
¥ 55,000 (released in 1983)
Commentary
Pre-main amplifier with CD direct function.
An audio current transfer system is adopted in which a total of four amplifier sections, a preamplifier section, a power amplifier section, and left and right amplifier sections, are electrically independent.
In this method, a current conversion amplifier is inserted between the preamplifier and power amplifier, and the output of the preamplifier is converted into a current signal. The voltage signal is then converted back into a voltage signal by a linear gain control attenuator installed at the final stage of the current conversion amplifier.
As a result, the effects of noise pollution factors such as contact resistance of switches and connectors and intrinsic impedance of wires, which could not be avoided with the conventional transmission method of voltage signal → voltage signal, can be almost ignored. In addition, the output impedance of the preamplifier section from the viewpoint of the power amplifier section becomes almost infinite, and the result is equivalent to the result of being disconnected from the viewpoint of electricity, and the performance is improved independently.
Legato linear system is used for the power amplifier section.
In this method, dynamic distortion such as switching distortion and crossover distortion is reduced by using an orthodox and simple fixed bias method in terms of circuit without adopting a method of moving bias value or changing power supply voltage value.
Dynamic distortion occurs because the operating range of the amplifying element used is narrow and the response speed in the high-frequency range is slow. To improve this, we have adopted a Hi-ft transistor with a wide operating range and a high response speed. By working in the ultra-cut-off range, the characteristic that no switching distortion is observed in the ultra-high-frequency range is realized.
The volume uses a linear gain control attenuator that can be used with the audio current transfer method. This volume draws a curve in which the impedance decreases as the gain is reduced. The SN ratio in actual use is greatly improved compared to using a normal variable resistor.
The CD Direct function is available. When this function is ON, you can jump through the function / tape monitor / subsonic filter / graphic equalizer switch / tone control circuit to enjoy a more direct sound.
Equipped with tone control with DEFEAT position.
It is equipped with an input / output terminal for graphic equalizer connection and an AUX/TV input terminal for front panel priority.
Large-capacity electrolytic capacitors for power supply and high-speed rectifier diodes are used.
Oxygen-free copper wire with polarity display is used for the power cord.
Equipped with a high gain equalizer for MC cartridges.
Equipped with a subsonic filter.
Equipped with speaker ON/OFF switch.
Model Rating
| Type | Pre-main amplifier |
| Circuit system | Current drive integrated stereo amplifier Low-noise, high-gain equalizer amplifier Bridge balanced current conversion amplifier All Stages Directly Connected Pure complimentary service SEPPOCL Legato Linear Amplifier FET buffer power supply |
| Effective power | 100W + 100W (1 kHz, both channel operation, 0.008% harmonic distortion rate, 6 Ω) 80W + 80W (20 Hz to 20 kHz, both channel operation, 0.008% harmonic distortion rate, 8 Ω) |
| Output bandwidth | 5 Hz to 50 kHz (40W output, 0.02% harmonic distortion rate, 8 Ω) |
| Harmonic distortion factor | 0.008% or Less (20 Hz to 20 kHz, 8 Ω at Rated Output) |
| Cross modulation distortion factor | 0.008% or Less (8 Ω at Rated Output, 60 Hz : 7 khz = 4 : 1) |
| Damping factor | 50 (1 kHz, 8 Ω) |
| Frequency characteristic | Phono : RIAA curve ± 0.2 dB Tuner, Aux, CD, Tape, Graphic EQ : 5 hz to 150 khz + 0 to 3 db |
| Signal-to-noise ratio | Phono MM:86dB Phono MC:75dB Tuner, Aux, CD, Tape, Graphic EQ : 98 dB |
| Input Sensitivity / Impedance | Phono MM : 2.5mV/50k Ω Phono MC : 170 μ V/100 Ω Tuner, Aux, CD, Tape, Graphic EQ : 150mV/50k Ω |
| Output Level / Impedance | Rec out : 150mV/4.7k Ω Speaker : Applicable impedance 6 Ω ~ 16 Ω Headphone : 24mW/8 ohm Graphic EQ : 150mV/4.7k Ω |
| Tone control | Bass : ± 10 dB (60 Hz, turnover frequency 300 Hz) Treble : ± 8 dB (25 kHz, 5 kHz turnover frequency) |
| Subsonic filter | 15 Hz or less, 6dB/oct. |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 140W |
| External dimensions | Width 430x Height 130x Depth 365 mm |
| Weight | 11kg |