Audio Database

The

DENON PMA-850
109,000yen(1977 release)

Description
 
The Integrated Amplifier which concentrated technology and was developed in many characteristics which are the basic engine performance of an audio play machine, such as a transmission characteristic, a dynamic range, distortion, and a cross talk.

Each unit part of MC head amplifier, EQ amplifier, flat amplifier, and power amplifier consists of full complimentary (symmetrical with phase assistant) circuits using both the transistors of NPNPNP over the whole page.
In each part, all use the first rank as NPN of high gain, and the differential stage using a PNP car transistor, and make the final stage the push pull. The eventh higher-harmonic-wave distortion was mutually negated by using such symmetrical circuit composition, and total and distorted reduction is realized.

Newly developed power transistor E.B.T (emitter ballast transistor) is adopted as a power amplifier part.
E.B. fT shows about 100MHz and the high (10 times over the past) and high speed switching characteristic, and T has improved the distorted characteristic of a high region by this.
Moreover, the power amplifier part has direct-current amplifier composition of ICL and OCL excellent in a transient response and the phase characteristic.

The mass toroidal transformer of 420VA which stored right-and-left channel independent winding wire in one package is adopted as a power-source part. Furthermore, a 20000-micro F mass block condenser is used for the right-and-left channel, respectively, and the dynamic cross talk is stopped by using an independent rectifier circuit.
Since the leakage flux (leakage flux) characteristic is extremely excellent, realization of high S/N is possible for a toroidal transformer.

In order to attain low noise-ization, it is in MC head amplifier and an equalizer amplifier part,While using the newly developed super-low noise transistor for the first rank, the Troy Dahl type (the multiplex shield of the silicon steel plate is given to the core of a case) who reduced to the limit the leakage flux of the power transformer used as the cause of reducing S/N is used,S/N of head amplifier and an equalizer amplifier part is improved.

The profit of MC head amplifier of PMA-850 is in inverse proportion to the impedance of the cartridge connected with the constituting principle of the circuit currently used.
The impedance and the Output voltage of a cartridge have a relation of direct proportion mostly, it is equalized automatically and the output of MC head amplifier does not need to adjust volume sharply for every cartridge.

The included control amplifier part can separate tone control completely with a direct couple switch, and power amplifier can be directly driven with the output signal of an equalizer amplifier part.
It is possible to enjoy itself by a thereby more simple play system.

Reliable gilding processing has been performed to the input terminal of Phono3.

In order to make distortion, S/N, and a cross talk into the minimum and also to make it stabilized, the dual bus line is adopted as a power-source part ground.

Internal Troy

Rating of a mode
Form Integrated Amplifier
<Power amplifier part>
Circuit system Whole page pure complimentary push pull system direct-current circuit
Output power (both channel drive) 85W+85W (8 ohms, 20Hz - 20kHz, THD 0.01%)
110W+110W (4 ohms, 1kHz, THD 0.05%)
THD 0.01% or less
Cross modulation distortion
(60Hz:7kHz=4:1)
0.02% or less (at the time of an Output-power equivalent amplitude output)
0.01% or less (at the time of the sine wave 1W equivalent amplitude output)
Output bandwidth 5Hz - 100kHz (IHF, THD 0.1%)
Transmission characteristic
(at the time of 1W output)
direct-current-100kHz+0 -1dB
Input sensitivity/impedance 1V/50kohm
Output load impedance 0.16ohm or less
Signal to noise ratio 122dB
Output terminal Speaker AorB: 4ohms - 16ohms
Speaker A+B: 8ohm-16ohm
Headphone jack
<Preamplifier part>
An Output voltage/impedance Pre out: 1V (rating), 20V (at the time of maximum-except-take-off and load 50kohm)
Rec out: 320mV (rating), 20V (at the time of maximum-except-take-off and load 50kohm THD 0.01%)
THD 0.03% (output 3 V:00)
Input sensitivity/impedance Phono1, 2 MM:2.5mV /, 50kohm
Phono3 MC: 0.37mV (cartridge impedance 40ohm o'clock)
Tuner, Aux, Tape:320mv/40kohm
Maximum permissible input (1kHz) MM:200mV
MC: 30mV (40ohms)
RIAA deflection Less than [ 20Hz-20kHz±0.2dB ]
Signal to noise ratio (IHF, A network) Phono MM: 89dB or more (at the time of an input short circuit)
Phono MC: 74dB or more (40ohms of input terminal o'clock)
Tuner, Aux, Tape: 100dB or more (at the time of an input short circuit)
Frequency response (Aux->Pre out) 5Hz-100kHz+0 -1dB (at the time of Tone defeat)
Tone control variable range Bass: ±8dB (100Hz)
Treble: ±8dB (10kHz)
Filter characteristic Subsonic filter: 20Hz, 12 dB/oct
High cut filter: 9kHz, 12 dB/oct
Loudness control Low-pass: +7dB (100Hz)
High region: +6dB (10kHz)
Muting -20dB
<Synthesis>
Power receptacle switched: One line, 100W
unswitched: Two lines, 250W (total)
Power source AC100V, 50Hz/60Hz
Power consumption 215W (Electrical Appliance and Material Control Law)
Dimensions Width 434x height 164x depth of 400mm (a base, a knob, a terminal included)
Weight 17kg