Audio Database

The

DENON PMA-740
59,800yen(1983 release)

Description
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The stereo Integrated Amplifier which carries the amplifier unreturned [ of 0dB ].

The power amplifier which eliminated the negative return loop unreturned [ of 0dB ] is carried.
This system is a thing adapting the technology developed by POA-8000 in which it does not return, and has structure using a direct distortion servo circuit. A direct distortion servo circuit compares the signal (main signal + distorted ingredient) and incoming signal which are acquired from the output side, detects only a distorted ingredient, then carries out phase inversion of this distorted ingredient, and is adding it to the input side.
Static distortion is driven into the domain of zero by this operation. Moreover, the noise which appears in the output side of amplifier was also regarded as a difference of an incoming signal, and is removed.
Since there is no feedback of a signal and time delay does not arise by this, dynamic distortion which affects the Hearing impression quality is suppressed. Moreover, in order that there may be no NFB circuit, it is not influenced by the back electromotive force from a speaker, but the distorted increase and generating at the time of speaker connection are suppressed.

The power transistor of Pc150W is adopted as a power amplifier part.

In order to correspond to the high dynamic range which digital sauce has, the large-sized transformer of a multiplex shield, the 20,000-micro F mass condenser, and the fast recovery diode are adopted as a power-source part.

The original super equalizer is carried in the equalizer part, and broadband-ization is realized.

The high-speed protection circuit is built in.

The

Rating of a mode
Form Integrated Amplifier
<Power amplifier part>
Circuit system Unreturned [ of 0dB ] power amplifier system
Output power
(both channel drive, a sine wave continuation output, 20Hz - 20kHz)
120W+120W (6ohms)
105W+105W (8ohms)
Input sensitivity/impedance 150mV/30kohm
THD (20Hz - 20kHz, Output-power-3dB o'clock) 0.005% or less
Cross modulation distortion
(at the time of a 60Hz:7kHz=4:1 and Output-power equivalent amplitude output)
0.0025% or less
TIM distortion Below a measurement limit
Slew rate }200v/microsecond or more
Output bandwidth (IHF, both ch(es) drive) 5Hz - 80kHz (THD 0.03%)
Frequency response (at the time of 1W output) 4Hz-150kHz+0 -3 dB
Output load impedance (1kHz) 0.1ohm
Output terminal Speaker AorB: 6ohms - 16ohms
Speaker A+B: 12ohm-16ohm
Headphone: 410mW/eight ohms
<Preamplifier part>
Circuit system Super equalizer system
Input sensitivity/impedance Phono MM: 2.5mV/47kohm
Phono MC: 0.2mV/100 ohms
Tuner, DAD/Aux, Tape:150mV/30kohm
The maximum except take-off/Output power 10V/150mV
RIAA deflection (MC) 20Hz-100kHz}0.3dB
THD (at the time of 1kHz and 8V output) 0.002% or less
<Synthesis>
Signal to noise ratio (IHF-A, input short circuit) Phono MM: 86dB (at the time of a 2.5mV input)
Phono MC: 70dB (at the time of a 0.25mV input)
Tuner, DAD/Aux, Tape: 106dB (at the time of a 150mV input)
Tone control Bass: }8dB (100Hz)
Treble: }8dB (10kHz)
Muting -20dB
Loudness characteristic Low-pass: +7dB (100Hz)
High region: +6dB (10kHz)
Power source AC100V, 50Hz/60Hz
Power consumption (Electrical Appliance and Material Control Law) 195W
Dimensions (a base, a knob, a terminal included) Width 434x height 112x depth of 398mm
Weight 10.2kg