DENON PMA-300ZA
¥ 49,500 (released in 1974)
Commentary
An improved pre-main amplifier based on PMA-300Z.
The power amplifier is a pure complimentary service circuit using a PNP NPN pair of silicon power transistors manufactured by Motorola of the United States, known for their excellent characteristics and durability.
The driver stage is Darlington connected, and all stages from the input terminal to the speaker terminal are directly connected OCL circuits.
The equalizer amplifier section is a 3-stage direct-coupled E-E negative feedback type using a low-noise NPN transistor. A high collector voltage of + 38 v provides a high allowable input, while a small and appropriate collector current provides a low noise level, providing a wide dynamic range.
The Phono input has two systems with different sensitivities, and can be used depending on the sensitivity of the cartridge.
The input sensitivity is set by changing the negative feedback amount of the equalizer amplifier. The amplifier gain is 32 dB for PHono1 and 22 dB for Phono2.
Equipped with Pre out and Main in jacks that can separate the Pre and Main.
Equipped with tone control.
The tone amplifier section uses a 2-stage direct connection circuit with a low-noise NPN on the first stage and an FET transistor on the second stage. The tone control is performed by changing the negative feedback by the volume. The emitter-follower circuit is also directly connected to the tone amplifier section so that the characteristics of the circuit are not affected by the output load.
The control volume has a special resistance curve with an 11-position click stop, giving a stepped curve and feel with a rotary switch, while retaining the inherent advantages of the volume type in which the curve can be continuously adjusted.
Equipped with low-cut filter and high-cut filter.
Equipped with a -20dB muting switch.
Equipped with a loudness control.
The protection circuit at the final stage adopts a current limiting method and is designed so that it does not exceed the safe operating range of the power transistor even when the load is short-circuited.
Model Rating
Type | Integrated amplifier |
Power Amplifier Unit | |
Circuit system | Pure complimentary service 2 power supply OCL circuit directly connected to all stages |
Rated output | 17W + 17W (8 Ω, THD 0.1% or less when both channels are operated) 19W/19W (8 Ω, single-channel operation, THD 0.1% or less) |
Total harmonic distortion factor | 0.1% or Less (at Rated Output) |
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1) | 0.1% or Less (Sine Wave, Amplitude Output Equivalent to Rated Output) |
Output bandwidth | 20 Hz to 20 kHz -1dB (THD 0.1%) |
Frequency characteristic | 10 Hz to 100 kHz + 0 -1dB |
Input impedance | 60k Ω ± 20% |
Input sensitivity | 1 Vrms (at rated output) |
Residual noise | 0.3 mVrms or Less (Input Terminal Short Circuit) |
Output impedance | 0.12 Ω or Less (5 Hz ~ 30 kHz, DF70 or More) |
Preamplifier Section | |
Maximum power output | Equalizer Amplifier : 9 V or More (THD 0.1% or Less) Tone control amplifier : 5 V or more (THD 0.1% or less) |
Total harmonic distortion factor | Equalizer : 0.03% (100, 1k, 10 khz, output 1 v) |
RIAA deviation | Phono1 : 30 Hz to 15 kHz ± 0.8 dB |
Input Sensitivity / Impedance | Phono1 : 2.4mVrms/60k Ω ± 20% Phono2 : 8mVrms/60k Ω ± 20% Tuner, AUX : 100mVrms/80k Ω ± 20% Tape (including DIN) : 500mVrms/120k Ω ± 20% |
Phono maximum allowable input (1 kHz) | Phono1:240mVrms Phono2:600mVrms |
Signal-to-noise ratio (IHF-A) | Phono1 : 70 dB or more Phono2 : 77 dB or more Tuner, AUX, Tape : 85 dB or more |
Output Level / Impedance | Tape rec : 100mVrms/1k Ω or less DIN terminal : 40mVrms/80k Ω or less |
Tone control | Bass : ± 11 dB (80 Hz) Treble : ± 9.5 dB (12 kHz) |
Filter | Low Filter : 100 Hz, 6dB/oct. High Filter : 7 kHz, 6dB/oct. |
<General> | |
Accessory terminal | Pre out : 1V/200 Ω Main in : 1V/60k Ω Headset : Compatible with 8 Ω stereo headphones |
Semiconductor used | NPN transistor : 23 pcs PNP transistor : 6 pcs FET : 2 Diode : 9 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 |