McIntosh MI347 - Black

Description

The Home Theater Power Amplifier of the McIntosh Custom Install Range

The McIntosh MI347 is the only Custom Install amplifier in the McIntosh lineup engineered specifically for a 7-channel surround configuration — the home theater standard from Dolby Digital 7.1 through baseline Dolby Atmos 5.1.2 and 7.1 configurations. It brings McIntosh power to a dedicated home theater room that prioritizes the immersive experience: clear dialogue, powerful action effects, convincing surround ambience. It is a natural partner to McIntosh MX-series audio-video processors (MX124, MX200) or to the MHT300 receiver when you want to add external power. The amplifier is deliberately understated: "meant to be heard more than seen" — simplified front panel, installable either in a 3U rack or out in the open, per the owner's preference.

Asymmetrical Power: 3 × 250 W + 4 × 125 W

The MI347's power distribution reflects the reality of a movie soundtrack: in a home theater, the most important speakers are the three front channels (front left, center, front right) because that is where most of the dialogue and the loudest, most prominent special effects resonate. So the MI347 delivers 250 W per channel into 8 ohms (300 W into 4 ohms) on each of the three front channels. The four surround channels, which drive the surround or ceiling ambience speakers — important but less power-hungry — each receive 125 W into 8 ohms (200 W into 4 ohms). That asymmetrical architecture is unique in the McIntosh multi-channel amplifier lineup and provides more power where it actually matters, without over-sizing the surround channels.

Closed-Loop Digital Class D Amplification, Passive Cooling

The MI347 uses closed loop digital switching amplifier stages paired with robust power supplies — a modern Class D design that reaches performance levels rarely heard in home theaters. The high efficiency of Class D means the MI347 does not require noisy cooling fans to maintain its nominal operating temperature. It also features an abundance of cooling vents on the top and sides of the chassis to further assist with heat dissipation — an important detail when the amplifier lives in a closed rack or a stacked hi-fi cabinet. 0.025% THD, 100 dB S/N below rated output, dynamic headroom 2.5 dB (8 Ω) / 3.5 dB (4 Ω), damping factor >85 (8 Ω) and >45 (4 Ω), frequency response +0/-0.9 dB from 20 Hz to 20 kHz. Direct Coupled output.

Rear Panel: XLR AND RCA on All 7 Channels, 5-Way Binding Posts

The MI347's rear panel offers one balanced XLR AND one unbalanced RCA input on each channel — 7 XLR inputs + 7 RCA inputs total across the 7 channels. The user (or integrator) picks the input format based on the A/V processor. Balanced XLR is preferred for long runs between the processor and the amplifier when they live in separate equipment racks. Speaker output through standard 5-way speaker binding posts — the classic hi-fi format that accepts bare wire, spade lugs, banana plugs, and pin lugs. Heavy-duty binding posts, easy to route cleanly inside an equipment rack.

Power Guard®, Sentry Monitor™, and Auto On/Off Protection

The MI347 carries the McIntosh proprietary protection technologies. Power Guard® continuously monitors the input signal and adjusts gain in real time to prevent amplifier clipping — critical protection for home theater speaker tweeters that can be damaged by sustained clipping. Sentry Monitor™ is a fuseless short-circuit protection circuit: it disengages the output stage before current exceeds safe operating levels, then automatically resets as soon as conditions return to normal — no fuse in the signal path, no manual intervention required. Eco-friendly signal-sensing auto on/off: the MI347 turns off automatically after a period without an input signal, and turns back on automatically when a signal appears on the input (typically, when you turn on your home theater processor). 3.5 mm Power Control ports to synchronize power-on and power-off with the rest of a McIntosh stack.

3U Rackmount Chassis With Removable Rack Ears

The MI347 is taller than the other McIntosh Custom Install multi-channel amps (MI128, MI254, MI1250, all 2U): it occupies 3U in a standard 19-inch equipment rack. That extra height accommodates the top and side cooling vents that keep the amp thermally happy in fanless operation. Rack ears are included (and removable for non-rack installation). Dimensions 17-1/2 × 6-1/16 × 21 in. (44.45 × 15.4 × 53.3 cm, including feet and front panel), 32.5 lb (14.8 kg), 1,500 BTU/h thermal output. Multi-color LED indicators on the front for each channel display channel status (signal presence, Power Guard® activation).

Common Questions

Why choose this product?

The McIntosh MI347 is the only McIntosh Custom Install amplifier engineered specifically for 7-channel home theater, with an asymmetrical power distribution calibrated for cinema: 250 W per channel on the 3 front channels (dialogue and main effects) and 125 W per channel on the 4 surround channels (ambience and effects). Fanless Class D closed-loop amplification with top and side cooling vents, 0.025% THD, 100 dB S/N. Balanced XLR AND unbalanced RCA inputs on each channel, 5-way speaker binding posts. McIntosh Power Guard® and Sentry Monitor™ protection. Signal-sensing auto on/off (turns on automatically when you start your processor), 3.5 mm Power Control ports. 3U rackmount with removable rack ears. Hand-assembled in Binghamton, New York.

Why is the power distribution asymmetrical?

Because the power required is not the same across all channels of a home theater system. The three front channels — front left, center, front right — carry most of the movie signal: actors' dialogue (center), main musical and action effects (front left and right), image movement across the front sound stage. The surround channels (the 4 others) carry ambience, echoes, off-screen object movement — important for immersion, but significantly less power-hungry. So the MI347 delivers 250 W on the 3 fronts and 125 W on the 4 surrounds. That distribution puts more power where it actually matters (the fronts), without over-sizing the effect channels. It's a classic serious-home-theater design choice, applied by McIntosh for the first time in a rack-mountable amplifier.

Can the MI347 be installed in an enclosed equipment rack?

Yes, the MI347 is designed for it. Very efficient Class D amplification that generates little heat, plus an abundance of cooling vents on the top and sides of the chassis to help passive dissipation (no noisy fan). 3U rackmount form factor — 5.25 inches high in a standard 19-inch rack — with the rack ears included (and removable if you'd rather install it in the open). 1,500 BTU/h thermal output. Plan at least 1U of empty space above and below the MI347 in a thermally loaded rack to keep operation optimal.

How do I expand the MI347 to a Dolby Atmos or DTS:X configuration?

The MI347 drives the 7 main channels of a Dolby Atmos or DTS:X configuration: the 3 front channels (LCR) + the 4 surround channels (front surround left/right, back surround left/right). To add the Atmos/DTS:X height channels — 2 channels for a 7.1.2 config or 4 channels for a 7.1.4 config — McIntosh explicitly recommends adding an MI254 (4 channels at 250 W/8 Ω) which drives the 4 height channels of a complete 7.1.4 layout (11 channels total, MI347 + MI254 = 11 channels of amplification). Alternative for a larger system: add an MI128 (8 channels at 120 W/8 Ω) which would drive up to 15 channels (7 + 8 = 15 channels).

What's in the Box

McIntosh MI347 7-Channel Power Amplifier

Rack-mount ears (removable) and mounting hardware

AC power cord

Power Control cable (3.5 mm)

Owner's manual