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