Marantz PM-90

Commentary

This is a pre-main amplifier with a thorough brush-up of basic performances by tackling "reproduction of stereo images" and "improvement of sound S/N" from the front.
It was developed in pursuit of sound quality in actual use condition rather than catalog specification.

Uses a 4-row active volume system to prevent S/N degradation during actual use.
As the input signal becomes smaller when the volume is reduced, residual noise in the pre-section is suppressed to obtain a high S/N ratio.

In the power amplifier section, we have constructed a high-speed, low-impedance voltage amplifier using cascode technology.
The power stage consists of a parallel push-pull bipolar transistor, and the driver stage uses a MOS FET to prevent electrical interference.

The power supply unit is composed of two power transformers, each of + and -, for a total of 500 va.
In addition, the current directions of the two transformers are set to be opposite to each other so as to cancel each other's leakage flux.

The chassis is made of zinc die-cast and is secured with 3 mm thick top panel and die-cast side panel to reduce vibration.

Equipped with an AC polarity indicator that allows you to check the polarity of the power cord at a glance.

Model Rating

Type	Stereo pre-main amplifier
Rated output	Class A operation : Class AB operation : 25W + 25W (8 Ω) 180W + 180W (4 Ω) 150W + 150W (6 Ω) 130W + 130W (8 Ω)
Total harmonic distortion factor	0.0015%
Frequency characteristic	10 Hz ~ 100 kHz + 0 -3dB
Signal-to-noise ratio	High Level:111dB
Input terminal	CD balance input : 1 system Line input : 4 lines Phono input : 1 system Tape input : 1 system Processor input : 1 system
Output terminal	Tape output : 1 system One processor output Speaker output : 2 channels
Power consumption	290W (Electrical Appliance and Material Control Law)
External dimensions	Width 454x Height 170x Depth 460 mm
Weight	27.0kg