Marantz MM7055 5-Channel Power Amplifier

Marantz MM7055 5-Channel Power Amplifier

The Marantz MM7055 is a five-channel power amplifier rated at 140 watts per channel into 8 ohms, designed to partner an AV pre-processor or a receiver with pre-amplifier outputs. It takes over the demanding work of driving the front, centre and surround speakers, leaving the processor to handle decoding, room correction and source switching. For a home cinema that sounds strained at high volume on a receiver alone, this is the classic and effective upgrade.

Key features

• 140 W per channel into 8 ohms, 170 W per channel into 6 ohms, five channels
• Current Feedback amplifier topology for fast, stable performance
• Balanced XLR and unbalanced RCA inputs on every channel
• Frequency response of 8 Hz to 100 kHz and 105 dB signal-to-noise ratio
• DC trigger input and output plus Marantz remote bus for system control
• Illuminated front-panel power meter with display-off option
• Large power supply and aluminium extrusion heat sinking for sustained output
• Gold-plated speaker terminals for secure, low-resistance connections

Why separate power amplification helps

An AV receiver shares one chassis and one power supply between amplification, video processing, decoding and networking. When a soundtrack asks all channels to peak together, that shared supply is tested and dynamics can flatten. The MM7055 devotes its chassis, transformer and heat sinking to amplification alone. The result is cleaner headroom for film effects, better control of demanding speakers at realistic cinema levels, and a system that stays composed rather than hardening when the volume rises during action scenes or orchestral peaks.

Amplifier design and measurements

Marantz uses its Current Feedback topology across all five channels, with identical output stage design so the tonal character stays consistent from front to surround. Rated output is 140 watts per channel into 8 ohms from 20 Hz to 20 kHz at 0.08 percent THD with two channels driven, rising to 170 watts per channel into 6 ohms. Input sensitivity is 1.2 V on the unbalanced RCA inputs and 2.4 V on the balanced XLR inputs, with a damping factor of 100 and voltage gain of 29 dB, figures that pair predictably with most processors and receivers offering pre-outs.

Connections and system integration

Every channel offers both an XLR balanced input and an RCA unbalanced input, selected per channel, so a processor with XLR outputs can use fully balanced connections while a receiver with RCA pre-outs connects just as easily. DC trigger in and out allows the amplifier to power up and down with the rest of the system, and the Marantz remote bus and flasher input support custom-install control. The front panel carries an illuminated power meter that can be dimmed or switched off for dark-room viewing.

Build, placement and pairing

The amplifier measures 440 x 183 x 384 mm and weighs 15.7 kg, so the rack or cabinet needs proper depth, ventilation and shelf strength. Power consumption is rated at 660 W with 0.2 W standby. It pairs naturally with Marantz AV processors and with any brand of receiver that provides five pre-amplifier outputs, and a two-channel sibling amplifier can be added later if the system grows to seven channels or more.

Choose the MM7055 when a receiver-based cinema has run out of clean volume, when speakers are known to reward stronger current delivery, or when building a separates system around a dedicated processor from the start.