Audio Database


Pioneer M-90
200,000yen(1986 release)

Stereo power amplifier which supplied unstintingly the technology which Pioneer can have and was completed in order to correspond to the digital source.

The power-source part has adopted the electrolytic capacitor which amounts to total 48,000micro F while it has prevented the cross interferencee by dissociating thoroughly and uses a large-sized transformer by right-and-left independency.
Moreover, the large-current supply capacity 47A is attained very much, such as using independently the bridge rectifier circuit by high speed low-noise diode for the each on either side positive and negative side.

4 parallel push pull stream composition of Pc=130W type is adopted as a power transistor.

Apart from the normal input terminal from control amplifier, compact-disk direct input terminal which links a compact disk player and power amplifier directly is carried. Moreover, the Line direct termination is also carried and those without こ are possible using the compact-disk direct termination said appearance.
It is also possible to have equipped this compact disk/Line direct termination also with the output-terminal for exclusive use, and to carry out a return to control amplifier.

In order to shorten a signal path if possible, a rear-panel side arranges the volume itself to the nearness of an input terminal, and it enables it to control it from a front through the remote shaft made from aluminum.

Switching distortion carries the non switching circuit TypeII to which the polish was applied further in the non switching circuit which is not generated theoretically, expands the area of switching distorted zero more, and is attaining much more wide band-ization.
Moreover, immediately after power-switch ON and at the time of the Taishin number input, the idle current which is carrying out the drift continuously by transition of outside temperature etc. is stabilized, and the occurrence of the thermal distortion resulting from this is suppressed.
Furthermore, the difference of an input signal and an output signal is detected and rectified, and the nonlinear distortion of an output stage is suppressed to 1/30 or less.

While reducing a magnetic distortion, in order to raise the amount of periodic damping by pasting of a different metals, the copper plating chassis is adopted.
Moreover, the copper plating screw is adopted also as a screw.

In addition to the insulator as four feet, the five-point type of mounting which also equipped the center of the main unit with the insulator is adopted. It has a structure which a heavy transformer supports firmly by this also at the hub.

In the large-sized size of 39mm x 98mm, the right-and-left independent indicator which displays an output skillfully is carried, and the Direct reading of the output transition from 2mW to 300W can be carried out without a change.
Moreover, in order to make peek power easy to read, the peek hold facility for 0.6 seconds is built in.
An indicator can also be turned off by a switchpoint.

Parts are selected carefully and used in order to realize higher quality.
The reliable oxygen-free-high-conductivity-copper line is adopted as product-line material. Moreover, the brass cap carbon resistor which suppresses a distorted occurrence, the oxygen-free-high-conductivity-copper line AC code to which the 70-micrometer Copper-foil substrate, resin case capacitor, gilding input pin-jack, large-sized terminal, and polarity window which reduces direct current resistance and an inductance was attached, etc. are adopted.

The output circuit changing switch of 4ohm/8ohm is carried.

Internal Power

Rating of a mode
Form Stereo power amplifier
Output power
(20Hz - 20kHz, both channel) drive)
200W+200W (4ohm)
200W+200W (8ohm)
THD (20Hz - 20kHz) 0.003% (at the time of 8 ohm and an Output power)
Cross modulation distortion (50Hz:7kHz=4:1) 0.002% (20Hz - 20kHz, 200W, 8ohm)
Input sensitivity/impedance Control Amp In, compact disk Direct, Line, Direct:1V/50kohm
Output-terminal compact disk/Line Direct Out, Speaker A, B, Headphone
Frequency characteristic 20Hz-20kHz+0 -0.1 dB
SN ratio 125dB (IHF, a short circuit and A network)
Supply voltage AC100V, 50Hz/60Hz
Power consumption 410W
Dimensions Width 457x height 154x depth of 430mm
Weight 20.9kg