Marantz PM-74D

Commentary

A pre-main amplifier developed by inheriting the design philosophy and technology of the PM-84.

Marantz's original Quarter A circuit is used. Up to 1/4 (quarter) of the maximum output, it operates in pure A class, and beyond that, it automatically shifts to AB class and exhibits 100W output.
In addition, the PM-74D is equipped with an AVSS that shifts the output supply voltage in conjunction with Quarter A. By shifting the output supply voltage according to the power, the AVSS allows the power element to operate in a region where distortion and noise are minimized. This allows the power element to operate in an ideal state at all power levels.

A direct switch connected directly to the flat amplifier is mounted on the CD and Phono inputs.
CD Direct is directly connected to the flat amplifier just by passing through the volume, and Phono Direct is played through the shortest path between the phono amplifier, volume, flat amplifier, and power amplifier.

A direct coupling with a low-noise FET is used for a high-level input such as CD to improve the SN ratio.

The circuit design of the preamplifier section has been completely revised, and an AIE (Absolute Isolated Earth) circuit is mounted.
In the AIE circuit, the ground of the left and right Chan Luu is completely separated to eliminate crosstalk distortion and improve the separation.

It has 7 input lines and 2 output lines.

The phono input uses a differential circuit plus 2-pole compensation phono dedicated IC with a high-Gm ultra-low-noise FET.

The power supply section is equipped with a large transformer and a large capacitor.

OFC wiring is used for the main wiring, and copper plated screws are used to improve sound quality.

Model Rating

Type	Pre-main amplifier
Rated output (both channel operation, 20 Hz to 20 kHz)	Class AB : 100W + 100W (8 Ω) Pure Class A : 25W + 25W (8 Ω)
Output bandwidth	5 Hz ~ 50 kHz (8 Ω load, THD 0.03%)
Total harmonic distortion factor	0.015% (20 Hz to 20 kHz, 8 Ω load)
Cross modulation distortion factor	0.015%
Frequency characteristic	20 Hz ~ 20 kHz + 0 -0.3 dB
Damping factor	100 (6 Ω Load)
Input Sensitivity / Impedance	Phono MM : 2.5mV/47k Ω Phono MC : 250 μ V/100 Ω Tape, Tuner, CD, TV/aux1, Video/aux2 : 150mV/20k Ω
RIAA deviation	20 Hz to 20 kHz ± 0.2 dB
S/N ratio (IHF-A network)	Phono MM:86dB Phono MC:75dB Tape,Tuner,CD,TV/aux1,Video/aux2:98dB
Phono maximum allowable input (1 kHz)	MM:140mV MC:14mV
Tone control	Bass : ± 10 dB (100 Hz) Treble : ± 10 dB (10 kHz)
Pwer	100 VAC, 50Hz/60Hz
Power consumption (Electrical Appliance and Material Control Law)	220W
External dimensions	Width 462x Height 164x Depth 376 mm
Weight	14.3kg