DENON PMA-300Z
¥ 42,800 (around 1973)
Commentary
This is a pre-main amplifier that has taken over the quality of PMA-300 as it is, and is more complete.
Based on the design policy of "excellent bare characteristics and moderate negative feedback", it uses a genuine complimentary service circuit (genuine complementary symmetrical output) with a PNP / NPN pair of silicon power transistor from Motorola USA.
As a result, a complimentary service Darlington circuit with perfect symmetry is obtained.
The smaller the output impedance of the main amplifier, which short-circuits the back electromotive force generated by the voice coil of the speaker, the better the damping.
The direct coupling of the two power supply system adopted in the PMA-300Z takes into consideration that the damping does not worsen even in the ultra-low frequency range, and the damping factor shows a sufficient value even outside the audible band.
It uses an output capacitorless (OCL) circuit that directly drives the voice coil of the speaker with a two power supply system.
In addition, in order to increase DC stability inside the device, a differential amplifier using a carefully selected monolithic IC is adopted. By using an IC with the same accuracy as that used in the amplifier circuit of the measuring instrument as an active device, it is combined with the uniform symmetry of four transistors constructed on the same silicon substrate, and stable operation is enabled.
The tone control section uses a 3-chip NF-type circuit with an FET in the middle stage.
The collector current of the first stage transistor is reduced so that operation is performed in a low noise level region. The 40 v power supply voltage, which is equivalent to that of a preamplifier, provides efficient dynamic range and linearity, and high S/N sound quality.
Model Rating
Type | All-silicon transistor stereo premain amplifier |
Power Amplifier Unit | |
Circuit system | Genuine complimentary service SEPPP OTL OCL circuit |
Music power | 22Wx2 (8 Ω) |
Rated output (when THD is 0.1% or less) | Single-channel Drive : 19W/19W (8 Ω) When both channels are driven : 17W + 17W (8 Ω) |
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1) | 0.1% or Less (at Rated Output) |
Frequency response (at 1W output) | 10 Hz to 100 kHz -1dB |
Output Bandwidth (0.1%) | 20 Hz to 20 kHz -1dB |
Input impedance | 60k Ω |
Input sensitivity | 1 V (input required for output 12 V) |
Damping factor | 70 or More (8 Ω, 5 Hz to 30 kHz) |
Residual noise | 0.1 μ W or Less (8 Ω) |
Preamplifier Section | |
Maximum power output | 5 v (Harmonic Distortion Factor 0.1% or Less) |
Harmonic distortion factor (output 1 v) | 0.03%(100Hz) 0.03%(1kHz) 0.03%(10kHz) |
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1) | 0.1% or Less (at Rated Output) |
Frequency characteristic | 10 Hz to 100 kHz ± 1 dB |
Input sensitivity | Phono1 : 2.4mV/60k Ω Phono2 : 8mV/60k Ω Tuner, AUX : 100mV/80k Ω |
Maximum Undistorted Allowable Input (1 kHz) | Phono1:240mV Phono2:600mV |
Equalizer characteristics | RIAA deviation within ± 0.8 dB |
Recording and reconnector | REC/PB (DIN terminal) Input sensitivity : 500 mV Output level : 40 mv |
Tone control | Bass : 80 Hz, ± 11 dB Treble : 12 kHz, ± 9.5 dB |
Filter | Low Filter : 100 Hz, -6dB/oct. High Filter : 7 kHz, -6dB/oct. |
<General> | |
Input terminal | Phono1, 2 Tuner, AUX, Main Input, Tape Play (RCA jack) |
Output terminal | Rec Out Speaker Out (2 systems) Pre Amp Out |
Semiconductor used | Transistor : 25 Diode : 14 pcs |
Power supply voltage | 100 VAC, 50Hz/60Hz |
Power supply fuse | 2.3A |
Power outlet | Total 350W Power switch interlock : 1 system Power switch not linked : 1 system |
Power consumption (Electrical Appliance and Material Control Law) | 42W |
External dimensions | Width 376x Height 140x Depth 302 mm |
Weight | 7kg |