Audio Database

The

DENON PMA-451
49,800yen(around the 1977 time)

Description
 
PMA-701, the PCC loading Integrated Amplifier which inherited the technology of PMA-501.

PCC is equipment which adds and negates a reverse cross talk to the cross talk of a phone pickup system.
In PMA-451, the attached record for adjustment is used, and two knobs are operated and adjusted. Thereby, an improvement hears to abbreviation-40dB in the most sensitive frequency band.

The power amplifier part consists of differential amplification whole page direct connection OCL circuits, it is low impedance power supply circuit composition, and a new style power transistor, such as double epitaxial structure and the Mie diffusion structure, is adopted as an output final stage, respectively.

In order to protect a speaker from an operation mistake or an accident, speed of response builds in the very quick reliable protection circuit.
Moreover, in consideration of the influence on sound quality, the relay of special structure is adopted also about a relay.

In order to improve the cross talk by interference between channels, the mutual intervention is reduced by separating the power source of the circuit composition which made the way become independent 2 system, and a power circuit with much current, and the power source of a preamplifier circuit with little current.

In order for the small signal sent from a record player to prevent deteriorating by leading about and the change-over switch of wiring, a phone input circuit is made into one line, and the input terminal is made to link with equalizer amplifier directly.
A shield line and stray capacitance could be made small by this, and input impedance is improved.

In order to improve a dynamic cross talk, the power-source part has Puri Maine another winding wire power transformer structure.


Rating of a mode
Form Integrated Amplifier
<Power amplifier part>
Circuit system Differential amplification whole page direct connection pure complimentary OCL circuit
Dynamic output (IHF) 140W (70W+70W, 8ohms)
Output power
(both channel drive, a sine wave continuation output)
45W+45W (8 ohms, 20Hz - 20kHz)
55W+55W (4 ohms, 1kHz)
THD (Aux in->SP out) 0.08% or less (at the time of an Output power)
Cross modulation distortion (60Hz:7kHz=4:1) 0.1% or less (at the time of an Output power Aux in->SP out)
Output bandwidth (IHF, both ch(es) drive) 5Hz - 50kHz
Output load impedance 0.16ohm or less
Output terminal Speaker AorB: 4ohms - 16ohms
Speaker A+B: 8ohm-16ohm
Headphone jack
<Preamplifier part>
Input sensitivity/impedance Phono: 2.5Vrms/50kohm
Tuner, Aux, Tape1, 2:150mVrms/85kohm
Phono maximum permissible input (Phono->Rec out) 150 or more (1kHz) mVrms
THD (1kHz) Phono->Rec out: Less than 0.008% (at the time of 3Vrms output)
0.1% or less (at the time of the maximum except take-off)
RIAA deflection 20Hz-20kHz±0.3dB
An Output voltage/impedance Rec out: More than 150mVrms/50kohm
Tone control Bass: 50Hz±10dB
Treble: 20kHz±10dB
<PCC section>
Maximum permissible input 9Vrms
After-cancellation phone cross talk Abbreviation-40dB
Transmission frequency response 10Hz-50kHz+0 -1 dB
<Synthesis>
At the time of a transmission frequency response 20Hz-20kHz±0.75dB
Signal to noise ratio (IHF, A network, an input short circuit) Phono: 75dB or more
Tuner, Aux, Tape1, 2:95dB or more
Cross talk (Phono->SP out) - 75dB or less (20Hz - 1kHz)
- 56dB or less (20kHz)
Power receptacle switched: Two lines, a total of 150W
unswitched: One line, 100W
Power source AC100V, 50Hz/60Hz
Power consumption
(Electrical Appliance and Material Control Law)
125W
Dimensions Width 430x height 142.5x depth of 310mm
Weight About 10.5kg
Attachment The record for adjustment