Audio Database

The

DENON PMA-540
65,000yen(around the 1980 time)

Description
 
The Integrated Amplifier which carries a super equalizer and a real drive circuit.

Not only at MM cartridge but at the time of MC cartridge use, it has the composition of having removed the capacitor from all the stages of the signal course from the Phono input terminal to the speaker output terminal.
It had realized by adopting the direct direct-current servo circuit carried also in PMA-970, and perfect Capacitor-Less composition shut out direct-current drift effectively, and has secured super-low-pass stability.

The super equalizer by which the combination was carried out in each merit of NF form (returned type) and CR form (unreturned type) is carried in the equalizer amplifier part, and outstanding RIAA deflection is realized.
The composition of a super equalizer consists of the NF form direct-current amplifier and CR form equalizing filter by low noise dual FET,The first rank considered it as the parallel differential amplification of dual FET of a direct direct-current servo system, and it has canceled direct-current temperature drift, improving S/N and a distortion.

A real drive circuit is carried and reduction of the distortion is aimed at.
Paying attention to operation of the amplifier at the time of speaker mounting, this circuit is the technology in which distortion of the amplifier at the time of reactive load was reduced, also in the time of high power, realized the good characteristic and has realized low distorted-ization.

The circuit composition of the power amplifier part is 3 "a stage differential pre-driver + Darlington connection complimentary push pull output stage" of "two steps of first rank low noise FET differential direct direct-current servo system + transistor differential."
Furthermore, the thing which you carry the zero crossing linear bias circuit, and is made to build in a high speed thermal feedback circuit,While developing the merit of non switching further and attaining stabilization of quick bias from the time of a power-source injection, high stability was realized to external factors, such as a temperature change and time progress, and not only banishment of switching distortion but reduction of crossover distortion is realized.

The real-time tone control circuit is carried in the tone circuit.
This circuit consisted only of a passive device required for tone control, is including it in some power amplifier, and has removed the mass capacitor harmful to sound quality from the signal course.

The power-source part consists of the power transformers and the 30,000-micro F block capacitors which gave the multiplex shield.

In order to reduce magnetic material as much as possible, L angle and an aluminum radiator are combined and the core of amplifier is summarized shapely.
Furthermore, the merit of a simple circuit, such as operating an input change part by remote control, and shortening a signal course sharply, is raised.

The direct couple switch is carried.

The Rec out off function to remove the influence on sound quality is begun, and a Subsonic Filter and loudness control are carried.

Rear
Internal

Rating of a mode
Form Integrated Amplifier
<Power amplifier part (Tuner in->SP out)>
Output power
(both channel drive, a sine wave continuation output, 20Hz - 20kHz)
100W+100W (4ohms)
80W+80W (8ohms)
Input sensitivity/impedance 150mV/40kohm
THD (20Hz - 20kHz, Output-power-3dB) 0.007% or less
Cross modulation distortion (an equivalent for 60Hz:7kHz=4:1 and an Output power) 0.005% or less
Output bandwidth (IHF, both ch(es) drive) 4Hz - 100kHz (THD0.1%)
Frequency response (at the time of 1W output) 1.5Hz-250kHz+0 -3 dB
Output load impedance (1kHz) 0.08ohm
Speaker output AorB: 4ohms - 16ohms
A+B: 8ohm-16ohm
<Preamplifier part (Input sensitivity/impedance is removed and it is Phono in->Rec out)>
Input sensitivity/impedance Phono MM: 2.5mV/50kohm
Phono MC: 0.25mV/100 ohms
Tuner, AUX, Tape:150mV/40kohm
The maximum except take-off/Output power 10V/150mV
RIAA deflection (MM, MC) 20Hz-100kHz±0.2dB
THD (at the time of 1kHz and 6V output) 0.002% or less
<Synthesis>
Signal to noise ratio (IHF-A, input short circuit) Phono MM: 88dB (at the time of a 2.5mV input)
Phono MC: 72dB (at the time of a 0.25mV input)
Tuner, AUX, Tape: 106dB
Tone control Bass: ±8dB (100Hz)
Treble: ±8dB (10kHz)
Subsonic Filter 18Hz, 6 dB/oct
Loudness control 100Hz : +7.5dB, 10kHz : +5.5dB
Power supply voltage AC100V, 50Hz/60Hz
Power consumption (Electrical Appliance and Material Control Law) 210W
Dimensions Width 434x height 112x depth of 390mm
Weight 9.7kg