Marantz PM-94

Commentary

Pre-main amplifier with Marantz's separate amplifier technology.

The output stage is a triple push-pull configuration using MOS FET.
MOS FET has characteristics such as "excellent high-frequency characteristics, high withstand voltage and high power can be applied at the same time", "because it operates only with majority carriers in principle, high input impedance higher than that of J-FET is realized", and "because there is little accumulation effect during switching, turn-off time is extremely shortened and high-speed switching is possible". Together with Marantz's original Quarter A, MOS FET realizes ideal operation.

Using a unique Quarter A circuit, it performs full class A operation up to 1/4 of the maximum output and automatically shifts to class AB operation up to the maximum output. This autoshift is controlled by an electronic control. It detects the output voltage of the main amplifier and controls the bias current with a high-speed switching circuit.
The detection speed of the PM-94 circuit is higher than that of the conventional Quarter A circuit, enabling smoother control.

In order to fully demonstrate the performance of the MC cartridge, two high performance MC transformers are mounted on the MC input independently on the left and right sides.
This transformer has a 2-coil configuration and uses double shielding in the core direction and winding direction. It has a quality close to that of the high-sound MC transformer "MC1000".
The step-up ratio is switchable between High and Low.

The power supply section is equipped with a large transformer and a 90,000 μ F large electrolytic capacitor.
In particular, toroidal transformers are shielded by three layers of silicon steel plates to prevent flux.

Copper-plated steel sheet material "Copper-Tight" is used throughout the chassis, and the uniform copper-plated finish of Copper-Tight is more effective than conventional copper plating.

Thorough tuning has been applied, such as using parts that have been examined through hearing.
We have adopted a pair electrolytic capacitor with equivalent characteristics and sound quality, and switches with improved sound quality by copper-plating. In addition, 70-micron thick circuit boards and oxygen-free copper wires are used.
In addition, in order to eliminate the change in sound quality caused by soldering, the condenser is fixed with screws and all screws are copper plated screws.

Equipped with a CD direct position. In this position, the input selector is directly connected to the flat amplifier by jumping to a stage such as an input selector or a tape monitor. Moreover, since the flat amplifier is an FET input, the change in input impedance is almost negligible even when the resistance of the master volume itself changes.

Equipped with HiFiVCR monitor position, you can enjoy music playback by HiFiVCR with the same feeling as a tape monitor.

Model Rating

Type	Pre-main amplifier
Rated Output (20 Hz ~ 20 kHz)	35W + 35W (Pure Class A, 8 Ω) 140W + 140W (Class AB, 8 Ω) 220W + 220W (Class AB, 8 Ω)
Output Bandwidth (THD 0.008%, 8 Ω)	10 Hz to 40 kHz
Total harmonic distortion rate (20 Hz to 20 kHz)	0.01% (4 Ω) 0.005% (8 Ω)
Cross modulation distortion factor	0.005%
Frequency characteristic	20 Hz ~ 20 kHz + 0 -0.2 dB
Damping factor	120 (8 Ω)
Input Sensitivity / Impedance	Phono MM : 2.5mV/47k Ω Phono MC (High) : 350 μ V/40 Ω Phono MC (Low) : 125 μ V/3 Ω Tape, Tuner, CD, Aux : 150mV/25k Ω
Output impedance	Pre out : 220 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, CD, Aux : 100 dB
Phono maximum allowable input	MM:220mV MC:24mV
Tone control	Bass : ± 10 dB (100 Hz) Treble : ± 10 dB (10 kHz)
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	395W
Maximum external dimensions	Width 454x Height 146x Depth 410 mm
Weight	23kg