Audio Database

The

DENON PMA-300Z
42,800yen(around the 1973 time)

Description
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The Integrated Amplifier which succeeded the quality of PMA-300 as it was and raised completeness more.

Based on the design policy of "the outstanding nakedness characteristic and a moderate negative return", the pure complimentary (pure phase assistant symmetrical output) circuit by the acknowledged silicon power transistor of U.S. Motorola, Inc., Inc. and the pair of PNP-NPN is adopted.
The complimentary Darlington circuit which shows perfect symmetry by this has been obtained.

Dumping becomes better as the Output load impedance of a main amplifier with the duty which short-circuits the back electromotive force generated in the voice coil of a speaker is small.
For the direct couple of 2 power-source systems adopted as PMA-300Z, consideration is carried out so that dumping may not get worse in super-low-pass one, and as for the dumping factor, value sufficient out of an audio frequency band is shown.

The Output Capacitorless circuit (OCL) circuit to which the voice coil of a speaker is made to drive directly by 2 power-source systems is adopted.
Moreover, in order to raise the direct-current stability inside an element, it is using IC of what has adopted the differential amplifier by the monolithic IC selected carefully, and is adopted as the magnification circuit of a measuring instrument, and this accuracy as an active device,Stable operation is conjointly enabled with symmetry with four uniform transistors constituted on the same silicon substrate.

NF type circuit of 3 stone composition which used FET for the middle stage is adopted as a tone control part.
The collector current of the 1st step of transistor was reduced so that it might be made to operate in the domain where a noise level is low, an efficient dynamic range and linearity were obtained with the power supply voltage of 40V equivalent to a preamplifier, and the good sound quality of S/N has been obtained.

Rear
Internal
Specification

Rating of a mode
Form All silicon transistor stereo Integrated Amplifier
<Power amplifier part>
Circuit system Pure complimentary SEPP OTL OCL circuit
Music power 22Wx2 (8ohms)
Output power (at the time [ THD 0.1% less than ]) At the time of a •Ð ch drive: 19W/19W (8ohms)
At the time of both ch(es) drive: 17W+17W (8ohms)
Cross modulation distortion (60Hz:7kHz=4:1) 0.1% or less (at the time of an Output power)
Frequency response (at the time of 1W output) 10Hz - -100kHz one dB
Output bandwidth (0.1%) 20Hz - -20kHz one dB
Input impedance 60kohm
Input sensitivity 1V (input which Output 12V takes)
Dumping factor 70 (8 ohms, 5Hz - 30kHz) or more
Remains noise 0.1 microwatt or less (8ohms)
<Preamplifier part>
Maximum except take-off 5V (0.1% or less of THD)
THD (output 1V) 0.03%(100Hz)
0.03%(1kHz)
0.03%(10kHz)
Cross modulation distortion (60Hz:7kHz=4:1) 0.1% or less (at the time of an Output power)
Frequency response 10Hz-100kHz}1dB
Input sensitivity Phono1:2.4mV/60kohm
Phono2:8mV/60kohm
Tuner, AUX:100mV/80kohm
The maximum-less distorted allowable input (1kHz) Phono1:240mV
Phono2:600mV
Equalizer characteristic RIAA deflection of less than }0.8dB
Recording-play connector REC/PB (DIN terminal)
Input sensitivity: 500mV
Output voltage: 40mV
Tone control Bass: 80Hz, }11dB
Treble: 12kHz, }9.5dB
Filter Low Filter: 100Hz, -6 dB/oct
High Filter: 7kHz, -6 dB/oct
<Synthesis>
Input terminal Phono1, 2
Tuner, AUX, Main Input, Tape Play (RCA jack)
Output terminal Rec Out
Speaker Out (two lines)
Pre Amp Out
The semiconductor used Transistor: 25 pieces
Diode: 14 pieces
Power supply voltage AC100V, 50Hz/60Hz
Power-source fuse 2.3A
Power receptacle Total 350W
Power-switch linkage: One line
Power-switch un-interlocking.: One line
Power consumption
(Electrical Appliance and Material Control Law)
42W
Dimensions Width 376x height 140x depth of 302mm
Weight 7kg