Audio Database


Pioneer M-Z1a
320,000yen(one set, the 1983 release)

Force required for power amplifier, and unreturned monophonic power amplifier polished up, selected carefully and used from the part in quest of the distorted tone quality which is not.

The super linear circuit is adopted as a voltage amplification part, with this scheme that cancels the nonlinearity of a transistor with a transistor with the nonlinearity in the reverse mode, the linear amplification was realized without the NFB loop and the problem resulting from NFB is solved.

LAPT (ensemble power transistor) with a high-speed responsibility is adopted as an output stage.
In order to obtain a linearity to the last, the electric-current burden per one stone is made light, and it is parallel six pieces, and is used, and a pure Class-A operation is carried out.

The double locked servo regulator who suppresses a variation of a middle point voltage to DC stabilization of an important outputting point with unreturned amplifier, and improves the robustness of a super linear circuit further is employed.
Furthermore, the special feature of unreturned amplifier is raised more by having the whole page hardwired-connection stream composition which put into practice and removed the coupling capacitor constituting the cause of coloring of sound.

Though it is monophonic amplifier, two power transformers are used for a transformer.
Source impedance is reduced by equivalence parallel connection, and also the power-source drive to an output stage is strengthened.

In order to remove the factor of a tone-quality failure, while changing the case of the capacitor into the glass from conventional aluminum, the carbon coating was given to the glasscase inside, and also the glasscase capacitor which added the enhancement to electrode foil is developed and adopted.

The mica capacitor of a high-performance and hi-reliability was adopted as the capacitor of a small capacity, it enclosed with the resin case by the high-density special epoxy resin, and the cross modulation distortion by oscillation of an electrode is prevented.

It changes to an iron cap at a drawer part, and the resistor which adopted brass cap carbon is adopted, and distortion is suppressed thoroughly.

Paying attention to the slight distorted occurrence by the magnetic substance, the aluminum material which is non-magnetic material was adopted as all, such as a chassis and a frame, and also the special resin was coated inside, and equalization of the shielding effect is measured.

To the printed circuit board, a mechanical intensity is high, and the glass epoxy which was excellent in the RF property is adopted.
And the Copper foil is made to reduce direct current resistance and an inductance by giving conventional about 4 time thickness of 140micro.

Oxygen free high conductivity copper was adopted as the place which uses oxygen free high conductivity copper for the product-line material of a signal system in addition through which a signal flows, or splicing fittings, and the thoroughgoing style for the improvement in a tone quality is taken.

The star-quad structure which used oxygen free high conductivity copper for the material was adopted as the pin plug code, the self-inductance of the code was reduced, and the flat transmission characteristics has been acquired to the high region by the low loss.

Since the polarity is unified until the power cord has adopted the mass code insulated doubly and also reaches [ from a power-cord core line ] even internal circuitry, AC line and a polar matching can be aimed at.

The protection network which detects the bads of an overload, a middle point voltage, and supply voltage is adopted.
When a middle point voltage carries out an unusual transition according to the outage of short-circuit of a speaker termination etc. by this, a speaker and power amplifier are separated.
Moreover, at the time of ON-OFF of a power switch, it operates as a muting circuit.

The light emitting diode peek power indicator is carried 20 point.
Peak value is directed without a range change for from 0.001W to the さ medical college 100W using a logarithmic comression circuitry.
Moreover, since the peek hold facility is carried, it is convenient for reading of peak value.

Internal Film
Glass LAPT

Rating of a mode
Form Unreturned monophonic power amplifier
Effective output (20Hz - 20kHz) 60W (8ohm)
Input sensitivity/impedance Input: 1V/50kohm
Output-terminal Speaker: 8ohm
Dumping factor 80 (20Hz - 20kHz, 8ohm) or more
Supply voltage AC100V, 50Hz/60Hz
Power consumption 220W (Electrical Appliance and Material Control Law)
AC outlet Power-switch un-interlocking.: One line, 100W
Dimensions Width 220x height 185x depth of 440mm
Weight 19.1kg