Pioneer Exclusive M4 Power Amplifier 50W Pure Class A Serviced

CONDITION

This unit is in excellent condition and works properly, and has been serviced. The transistors have been replaced, and all of the electrolytic capacitors except for two large ones have been replaced (with Nippon Chemi-Con capacitors). One of the terminal knobs on the speaker terminals is missing, but the unit can be used without any problem.

ABOUT THIS ITEM

The Pioneer Exclusive M4 is a high-end stereo power amplifier made in Japan by Pioneer, produced from 1974 to 1980 as part of Pioneer's prestigious Exclusive series, the company's flagship high-fidelity line. It delivers 50 watts per channel into 8 ohms in pure Class A operation, prized for the smooth, natural, and highly refined sound that Class A amplification is renowned for. The amplifier uses a pure-complementary OCL (output capacitor-less) circuit with a single-stage differential input and a two-stage Darlington quadruple push-pull output stage, achieving low distortion and excellent linearity. Built to the exacting standards of the Exclusive range, it features a heavy, rigid chassis, a substantial power supply with a large transformer, and extensive heat sinking to handle the constant high heat of Class A operation. Robust speaker terminals and a clean, understated front panel complete the design. Combining the musicality of pure Class A with Pioneer's finest engineering, the Exclusive M4 remains a highly sought-after vintage power amplifier among audiophiles and collectors who appreciate classic Japanese high-end audio.

・Power Supply Voltage: AC 100V, 50/60 Hz (Japanese domestic model). Please use a suitable step-down transformer in 110–240V regions.

— Grape Japan