Audio Database

Image of A-120
Commentary

A dynamic / non-switching pre-main amplifier that employs a dynamic power supply system and non-switching circuit to cope with the expansion of the dynamic range of the source.

Pioneer's original dynamic power supply system is used for power supply.
The input signal is detected by the level detector, and the low voltage section (VLWhen the output exceeds a certain level, the high-voltage section (VH).
In addition, Pioneer's original non-switching circuit is used in the power section, which in principle does not cause switching distortion that stains music.

In order to increase the purity of the sound, the MC input to the speaker output is a simple 2-amp configuration.
High-level signals such as Tape, Tuner, and AUX are directly input to the power amplifier. Moreover, by using a high-gain equalizer amplifier, the amplifier circuit up to the speaker output is only two amplifiers even when playing back the MC.
In addition, DC servo is used for both the equalizer amplifier and the power amplifier to realize a completely non-coupling capacitor.

The equalizer section uses a DC servo high-gain equalizer with a low-noise dual FET at the first stage.

A large-capacity transformer and an electrolytic capacitor with a total capacity of 40,000 μ F are used in the power supply section.

Equipped with a line straighter function, it passes through tone circuits and loudness circuits with a single switch, simplifying the signal path and obtaining high quality sound.

The power cord is double-insulated.

Equipped with an LED peak power indicator that displays the peak value of the output at 3 points in a circuit with excellent transient response. Equipped with a sensitivity selector switch, it can respond to the playback level.

An LED is mounted in the center of the slide knob of the tone control, and the LED lights up when the line straight function is off so that the position of the knob can be known.

Model Rating
Type Pre-main amplifier
Effective power 120W + 120W (20 Hz to 20 kHz, double-channel drive, 8 Ω)
Harmonic distortion factor (20 Hz to 20 kHz) 0.003% (at effective output)
Intermodulation distortion factor (50 hz : 7 khz = 4 : 1) 0.003% (at effective output)
Output bandwidth 5 Hz ~ 55 kHz (IHF, both channel drive, THD0.01%)
Output terminal Speaker (4 Ω ~ 16 Ω) : A, B, A + B
Tape Rec:150mV
Damping factor 70 (20 Hz ~ 20 kHz, 8 Ω)
Input Sensitivity / Impedance Phono MM : 2.5mV/50k Ω
Phono MC : 0.2mV/100 Ω
Tuner, AUX, Tape Play1, 2 : 150mV/50k Ω
Phono maximum allowable input (1 kHz, THD0.005%) MM:150mV
MC:11mV
Frequency characteristic Phono MM : 20 Hz to 20 kHz ± 0.2 dB
Tuner, AUX, Tape Play : 5 hz to 100 khz + 0 to 3 db
Signal-to-noise ratio
(IHF, A-network, short circuit)
Phono MM:88dB
Phono MC:70dB
Tuner, AUX, Tape Play : 110 dB
Tone control Bass : ± 10 dB (100 Hz)
Treble : ± 10 dB (10 kHz)
Filter Low : 15 Hz, 6dB/oct.
Loudness contour (at Volume -40dB) + 6 dB (100 Hz), + 3 dB (10 kHz)
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption (Electrical Appliance and Material Control Law) 260W
External dimensions Width 420x Height 131x Depth 411 mm
Weight 12.0kg