Marantz Model 50: Excellent all-round amplifier

The Marantz Model 50 amplifier serves as the successor to the Marantz PM8006, showcasing a redesigned front panel that reflects the latest industrial design trends of Marantz products. Additionally, the manufacturing of this new series has transitioned from Japan to Vietnam. The preamplifier section of the Marantz Model 50 features a fully discrete amplifier circuit with current feedback, a hallmark of Marantz Hi-Fi amplifiers.

This sophisticated amplifier circuit has been refined by Marantz over the years, offering high speed, an excellent signal-to-noise ratio, and minimal distortion. Furthermore, the board layout retains the equal length and parallel configuration of the left and right channels from the previous model, which enhances spatial representation. The preamplifier circuit incorporates low distortion HDAM technology, representing an evolution of the original Marantz high-speed discrete amplifier known as “HDAM (Hyper Dynamic Amplifier Module).”

The Marantz Model 50 enhances the instantaneous current capacity of its power supply to 66A by utilizing a parallel push-pull configuration in the output stage. To effectively manage the heat produced by the transistors and ensure stable operation, it incorporates a robust extruded aluminum heatsink. This amplifier delivers a powerful output of 100W + 100W at 4 ohms, consistently offering stable, high-quality sound regardless of the speakers used or the volume level. The circuit design features a Schottky barrier diode with minimal leakage current, while the smoothing circuit is equipped with exclusive Marantz capacitors (18,000uF / 63V x 2), leveraging expertise from high-end models to achieve both substantial capacity and rapid power supply performance.

In order to minimize crosstalk and group errors between channels, a high-performance volume control chip with excellent performance beyond the audible range is used. Since there is no crosstalk or volume difference between the left and right channels, which is inevitable when using mechanical volume, spatial expression can be greatly improved. By combining this volume control chip with HDAM and HDAM-SA2, a high-performance linear control/volume circuit is created. In addition to the main chassis, a four-layer chassis consisting of three 1.0 mm thick steel plates provides reliable support for the circuit board and power transformer, eliminating the negative impact of vibration on sound quality. The center of gravity is low, ensuring stable sound.

The Marantz Model 50 features a phono preamp that is compatible with MM cartridges. By using a J-FET input and adding a passive DC servo circuit, we eliminate AC coupling capacitors and improve the purity of the signal path. In addition, the sound tuning uses high-quality parts such as high-quality copper foil film capacitors, which are also used in high-end models, to achieve a rich analog sound.

The speaker output features a unique Marantz speaker terminal (SPKT-1+). Its core is crafted from solid brass, and the surface treatment consists of a single thick layer of nickel plating, moving away from the conventional two-layer approach of nickel base plus gold plating. It accommodates cables with a diameter of up to 4.5 mm, securely fastened with large screws. Additionally, it is compatible with Y-lugs and banana plugs. The input and output terminals are gold-plated to enhance durability and resist wear over time, ensuring reliable connections for extended use. Furthermore, both the CD input and Phono input are fitted with robust RCA connectors made from machined brass.

Marantz Model 50 Specifications 

• Output Power 2 x 70 W (8 Ohms); 2 x 100 W (4 Ohm)
• Frequency response 10 Hz – 70 kHz
• Total harmonic distortion 0.08%
• Damping factor 100
• Signal-to-noise ratio 102 dB, MM phono equalizer: 83 dB
• Input sensitivity/input impedance 200 mV/20 kOhm
• Sensitivity/impedance at the phono equalizer input 2.2 mV/47 kOhm
• Digital filters Filter 1 (slow roll-off), Filter 2 (sharp roll-off)
• Discrete amplifier modules HDMA-SA2, HDMA-SA3
• Inputs 4 gold-plated line RCA, gold-plated RCA MM phono equalizer connectors
• Outputs 6.3 mm for headphones, RCA for recording, Pre Out, subwoofer output
• Others 2 D-Bus system bus connectors, IR connector, ground terminal Speaker
• output 4 pairs of gold-plated screw terminals
• Linear power supply with toroidal transformer and Schottky diodes
• Power consumption 220 W, standby: 0.3 W
• Dimensions (WxHxD) 442x130x431 mm
• Weight 14.4 kg