Marantz Esotec PM-4 (1980)

The Integrated Amplifier which can switch a pure Class-A and AB class.

In addition to pure Class-A 15 W/ch, the change of AB class 60 W/ch is attained. And in order to raise the quality of AB class even to the level of a pure Class-A, the high speed high fT transistor which took high high region cut-off frequency with 90MHz is adopted as the power stage. Switching distortion which is a fault of AB class is banished to a limit.

Good dual FET of the pair property was adopted as the input stage of a power amplifier part, and the property failure by an impedance variation is prevented with the source follower stream composition. Moreover, both a Class-A and AB class can be enjoyed by switching the bias current of an output stage. A super high ft transistor with a cut-off frequency of 90 MHz is adopted as a power element, and switching distortion is suppressed to the relative minimum.

Marantz PM-4 Esotec Series, Integrated Amplifier

Class: A-B Sine Power:

Class A: 15 W + 15 W (8Ω),

Class A-B: 60 W + 60 W (8Ω)

THD: 0,015% (20Hz - 20kHz at the time of an 8Ω load intensity and an Output power)

Cross modulation distortion (60Hz:7kHz=4:1): 0.015% (at the time of an 8Ω load intensity and an Output power)

Dumping factor (an 8Ω load intensity, 1kHz): 70

Transmission range: 5 - 100,000 Hz +0 -2 dB

Frequency response: 20 - 20,000 Hz -0, 3 dB

Distortion: 0.015%

Tone control:

Bass: ±10dB (100Hz)

Treble: ±10dB (10kHz)

Input sensitivity/impedance:

Phono 1, 2 MM: 2.5 mV/47 kΩ

Phono 2 MC: 2 00 mV/100Ω

AUX, tuners, tape 1, 2: 150 mV 25 kΩ

RIAA phono: 20 - 20,000 Hz, ±0.25 dB

Signal-to-Noise ratio:

Phono MM: 84 dB

Phono MC: 64 dB

AUX, tuners, tape: 104 dB

Phono max. Input: 330mV (MM); 25 mV (MC) at 1kHz

Inputs: 2 x phono, switchable phono 1: MM + MC, Phono 2: MM, 2 x tape

Outputs: 2 x speaker, headphones

Voltage: 110/120/220 V AC, 60/60 Hz

Power consumption: 150 watts

Dimensions (W x H x D): 416 x 117 x 334 mm

Weight: 9.5 kg

Marantz PM-5 ESOTEC

A stereo pre-main amp with Class A or Class AB choice. In Class A it produces 20 W RMS per channel; in Class AB it gives 80 W RMS per channel.

It has a highly original low TIM design, DC concept and all stage pp circuits. The MC amp and the phono Equalizer are designed to minimize TIM. By reducing the impedance of Phono Eq elements, we have given the PM5 a signal-to-noise ratio of 86 dB. In the choice of parts, in design and in materials first priority has been given to producing superb sound. Whatever it may cost.

In PM-5, it has a whole page perfect push pull DC amplifier stream composition that TIM distortion should be banished from all the corners in amplifier, and a nakedness property is improved. Even if it does not apply a lot of NFB, the TIM and the static characteristics are improved.

In order to raise the operational stability of a power transistor, a newly developed heat-pipe scheme is adopted as a heat-dissipation organization. Since heat is drawn out of a circuitry and it cools by a radiator, a transistor can be arranged in an ideal location and simple-izing of a circuitry and a Low-noise-izing are raised. Moreover, the mass capacitor developed for audios and the powerful power transformer which was filled up with the special resin, took heat-resistant measures and was miniaturized are adopted as a power-source part. 

Especially a phone amplifier block is the low distortion and high S/N ratio design sumptuously using a transistor. And the straight DC circuitry to which phone amplifier is direct connected to the power stage is taken in, and the quality of the disk play is raised.

Furthermore, highly precise MC head amplifier and a subsonic-speed circuitry are built in phone amplifier.

A subsonic speed is used only to an equalizer and is attaining simple-ization of other functions.

A tone control carries out "the ±8dB variable" of "100Hz" which is a right-and-left standalone version which a fine balance can adjust, and the "10kHz." And adoption of a highly precise volume has realized the entire flat response at the middle point of a thumb. 

The peek power meter of a window is suddenly equipped in the center of the front panel.

It differs from the bar window, and since light emitting diode displays power on a point in a pure Class-A and AB class, clear moreover, the Direct reading of the exact output can be carried out.

Moreover, under meter, the dubbing circuitry in which a mutual sound recording is possible, and two speakers hear it from the deck to the deck, it compares, and abundant functionalities which can perform a simultaneous play, such as a speaker multiple contact switch, are incorporated. 

Specifications:

Class B Power:

2x 80W (20Hz...20kHz, 8 Ω, 0,025%THD);

2x 100W (20Hz...20kHz, 4 Ω, 0,05%THD)

Class A Power:

2x 20W (20Hz...20kHz, 8 Ω,  0,015%THD)

Bandwidth:  7 Hz...50 kHz

Frequency Response:

Aux, Tape :  5 Hz...100 kHz (+0dB, -2dB)

Riaa :  20 Hz...20 kHz (±0,2dB)

Power Bandwidth:  5 Hz...90 kHz

Intermodulation Distortion:  0,015% (8 Ω )

Damping Factor:  100 (8 Ohm)

Inputs:

Phono MM :  2,2 mV / 27 / 47 / 100 kOhm

Phono MC :  220 µV / 75 Ohm

Aux, Tape ;   150 mV / 40 kOhm

Maximum Input:

Phono MM :  220 mV (1kHz)

Phono MC :  20 mV (1kHz)

S/N Ratio (IHF-A) :

Phono MM :  86 dB

Phono MC :  70 dB

Aux, Tape :   108 dB

Power Consumption:  350 W

Dimensions:  416 x 146 x 332 mm

Weight:  13 kg.