Audio Database


This is a pre-main amplifier equipped with Marantz digital support technology and designed for high sound quality with Quarter A and AVSS.

A Quarter A circuit has been developed and installed on the PM-84 in order to achieve both high output, which does not clip even at high level, and quality at low output, which reproduces low level.
This Quarter A operates in pure A class with excellent linearity for low level up to 1/4 (quarter) of maximum output, and moves to AB class at higher level to realize high power.
Each operation achieves a smooth shift by controlling the bias current with a high-speed switch circuit.

Equipped with an AVSS (Auto Voltage Shift Supply) that shifts the output supply voltage according to the power. The optimum output supply voltage allows the power element to operate in a region with minimal distortion and noise, etc., realizing high quality at all power levels from small output to large output.
Moreover, improves stability by suppressing unnecessary temperature rise at low power.

Designed for low impedance, it maintains power even when the speaker impedance momentarily fluctuates to an extremely low value.

Equipped with a direct switch, power is directly connected to enable higher SN ratio and high-speed signal transmission.

Analog disk playback is handled by configuring a phono amplifier with a dedicated phono IC and dual FET.
In addition, it has a 2-position MC input.

All basic parts, including the power supply, are strictly checked through hearing tests, and more than 100 parts are replaced.
The power supply section is equipped with a high regulation large transformer of the separate amplifier class and a newly developed custom electrolytic capacitor. In addition to the copper chassis, 2/3 of the screws used are copper screws. This structure emphasizes sound quality.

The side wood was sold separately.

Model Rating
Type Pre-main amplifier
Rated output 120W + 120W (Class AB, 8 Ω, 20 Hz to 20 kHz)
30W + 30W (Pure Class A, 8 Ω, 20 Hz to 20 kHz)
190W + 190W (4 ω, 1 kHz)
Output Bandwidth (8 Ω, 0.03% THD) 5 Hz to 40 kHz
Total Harmonic Distortion Factor (20 Hz to 20 kHz, 8 Ω) 0.015%
Cross modulation distortion factor 0.015%
Frequency characteristic 20 Hz ~ 20 kHz + 0 -0.2 dB
Damping factor (8 Ω) 120
Input Sensitivity / Impedance Phono MM : 2.5mV/47k Ω
Phono MC : 250 μ V/100 Ω
Phono High MC : 2.5mV/1k Ω
Tape, Tuner, Aux, CD : 150mV/47k Ω
Output impedance Tape out : 270 Ω
RIAA deviation 20 Hz to 20 kHz ± 0.2 dB
Signal-to-noise ratio (IHF-A network) Phono MM:90dB
Phono MC:76dB
Tape, Tuner, Aux, CD : 100 dB
Phono maximum allowable input MM:220mV
Tone control characteristics Bass : ± 10 dB (100 Hz)
Treble : ± 10 dB (10 kHz)
Subsonic filter characteristics 50Hz
Pwer 100 V, 50/60Hz
Power consumption 290W
External dimensions Width 416x Height 146x Depth 410 mm
Weight 18kg
Sold Separately Sidewood WPM-84 (¥ 4,000)