Audio Database

The

Pioneer A-200
169,000yen(1982 release)

Description
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The Integrated Amplifier developed on the theme of high-quality-izing and dynamic-range-izing of the amplifier itself.
The dynamic power supply scheme and the non switching circuit were adopted, and the high power which has a quality in an overall reflecting the thought of real dynamism is realized.

Since it corresponds to extensive dynamic-range-ization of the source and the speaker has been fully sounded also with the time of the Dainyuu power, the dynamic power supply scheme has been adopted as a power-source part.
It is the power circuit of this scheme consisting of two power supply sections, a low-voltage part (VL) and a high-voltage part (VH), usually driving only in a low-voltage part with signal level, and driving in a high-voltage part at the time of better and the Dainyuu power,Thereby, a loss of an output stage decreases sharply and makes high power possible.
Moreover, since a high-voltage part receives a signal wave form and it always follows with a fixed voltage value, it does not set a wave-like deficit, either.
Furthermore, since it is the design of locking as long as a signal continues while the high-voltage part had been locked when the Taishin number repeats in a wide area, the wave-like deficit by being late has also been prevented.
And the transformer had little magnetic flux leakage, the large-sized toroidal transformer characterized by a high regulation was adopted, and the electrolytic capacitor put into practice carrying eight and considering it as the large capacity of total 176,000micro F etc., and has realized low-impedance-ization. Moreover, nonmagnetic-ization, such as using copper lead wire and an oxygen-free-high-conductivity-copper line for the part of a power-source part, was put into practice, and a harmful magnetic distortion is banished.

The non switching circuit which has the established reputation which realized switching distorted zero in a power part is carried.
By work of the original high speed bias servo circuitry of Pioneer, a bias current is controlled according to an input signal, and this is pressing down the dirt of the music by switching distortion fundamentally by the scheme which always maintains a transistor at operating state.

The FET buffer circuitry was adopted between the voltage amplification part and the power amplification part, the voltage amplification part and the power amplification part were separated completely, and the nakedness property before applying NFB is improved sharply.
Even if the input impedance of FET is infinitely near and the property top power amplification part receives a load-impedance variation,Since it does not appear in the influence's input side, and also an operation of a voltage amplification part is stabilized and it can drive by a low-power-output impedance in a power amplification part (constant-voltage drive),Suppress the distorted occurrence by the nonlinearity of a power amplification part, and the influence of the reaction signal from a speaker is eliminated, and also much more low-distortion-ization of a power part is realized.

MC head amplifier considers from an input to an output as a push pull stream composition, and also makes the input the parallel push pull by super-low-noise FET. Moreover, consideration that the feeding back point of DC servo is made into the 2nd step of bias power-source part instead of the first rank, and a servo circuitry does not affect an SN ratio is taken.
As a result, the SN ratio was set to 74dB and has realized the outstanding property for which it presses only in the 76dB grip which is the theoretical threshold value by thermal noise, such as a transistor in this circuit system.

DC servo circuitry is adopted as each of MC head amplifier, an equalizer amplifier, and power amplifier.
This removed all the coupling capacitors from MC input to the speaker output, whole page non coupling-capacitor-ization is attained, and while losing the care about coloring of the sound resulting from a capacitor etc., the high-resolution tone quality is realized.

The line straight switchpoint which links an equalizer amplifier and power amplifier directly and with which a tone quality with a high purity is obtained is carried.
A tone control, the mode, and a balance volume are passed and a signal path is made simple.

The nonmagnetic part is adopted, in order to suppress a magnetic distortion which has an ill effect on a tone quality and to obtain a tone quality with a higher purity.
Copper lead wire is altogether adopted as the semiconductor used for each amplification stage, and copper is used also for the lead line cap of main resistors, such as an emitter resistor.
Moreover, copper is used for the lead wire of main capacitors, and the oxygen-free-high-conductivity-copper line is used for main product-line material.

The copper plating was given to the chassis and also the resonance of a frame is prevented as an H type structure.
Furthermore, the cross interferencee is prevented by intercepting separations of Lch of power amplifier, an independency of Rch, the Taishin number system, and a small signal system, equalizer amplifiers, and all the MC head amplifier on a structure.

The very-thick power cord of a double insulation structure is adopted as a power cord.
Furthermore, paying attention to sound changing with the polarities of AC line, the thorough mandatory of the polarity of how to roll a transformer or a power cord is carried out.

Internal
H Power
Part

Rating of a mode
Form Integrated Amplifier
Effective output 200W+200W (20Hz - 20kHz, both channel drive, 8ohm)
THD (20Hz - 20kHz) 0.002% (at the time of an effective output)
Cross modulation distortion (50Hz:7kHz=4:1) 0.002% (at the time of an effective output)
Output bandwidth 5Hz - 65kHz (IHF, both channel drive, THD0.01%)
Output-terminal Speaker(4ohm-16ohm): A, B, A+B
Tape Rec:150mV
Dumping factor 140 (20Hz - 20kHz, 8ohm)
Input sensitivity/impedance Phono man month: 2.5mV / 50kohm
Phono MC: 0.15mV/100ohm, 33ohm, 8ohm
Tuner, AUX, Tape Play1, 2:150mV / 50kohm
Phono maximum permissible input (1kHz, THD0.0008%) MM:300mV
MC:18mV
Frequency characteristic Phono man month: 20Hz-100kHz}0.2dB
Tuner, AUX, and Tape Play:1Hz-200kHz+0 -3 dB
SN ratio
(IHF, A network, a short circuit)
Phono MM:90dB
Phono MC:74dB
Tuner, AUX, Tape Play: 115dB
Tone control Bass: }6dB (100Hz)
Treble: }6dB (10kHz)
Filter Low: 15Hz, 6 dB/oct.
Supply voltage AC100V, 50Hz/60Hz
Power consumption (Electrical Appliance and Material Control Law) 360W
Dimensions Width 420x height 150x depth of 420mm
Weight 19.0kg