McIntosh MI347 7-Channel Home Theater Power Amplifier
The McIntosh MI347 is a high-performance 7-channel power amplifier designed specifically for modern home theater systems. Its efficient closed-loop digital switching architecture delivers greater power to the three most demanding front channels while providing substantial output for four surround or height channels, all from a compact, fanless 3U chassis.
The front left, center and front right channels each deliver 250 watts into 8 ohms or 300 watts into 4 ohms. The remaining four channels deliver 125 watts into 8 ohms or 200 watts into 4 ohms, making the MI347 well suited to conventional 7-channel theaters or as the primary amplifier in a larger Dolby Atmos or DTS:X system.
Purpose-Built Power for Home Theater
Movie soundtracks place the greatest demands on the front soundstage, where dialogue, music and the most powerful effects are concentrated. McIntosh designed the MI347 around that reality. Its three higher-powered front channels provide additional dynamic headroom for the left, center and right speakers, while the four surround channels efficiently power surround, rear or overhead speakers.
This channel layout makes the MI347 a natural partner for the McIntosh MX200 A/V Processor. Systems requiring more than seven amplified channels can supplement it with an additional multichannel amplifier for height, surround or secondary-zone speakers.
Closed-Loop Class D Amplification
The MI347 uses sophisticated closed-loop digital switching amplifier circuits paired with robust power supplies. This highly efficient Class D design produces substantial output without requiring cooling fans, helping preserve a quiet equipment room while reducing the heat and space demands associated with many traditional multichannel amplifiers.
Ventilation openings across the top and sides support passive heat dissipation. The understated exterior is intended to integrate neatly into a dedicated A/V rack, yet its black glass front panel, illuminated McIntosh logo and silver trim retain the brand’s familiar visual identity.
Rack-Friendly Installation
At only 3U high, the MI347 is built for custom-installed home theaters and equipment racks. Removable rack-mounting brackets are included, allowing it to be installed in a standard 19-inch rack or placed on a conventional equipment shelf.
The amplifier measures 17-1/2 inches wide without the rack ears, 6-1/16 inches high including its feet and 21 inches deep including the front panel and connected cables. It weighs 32.5 pounds, making it considerably easier to place and service than many large traditional multichannel amplifiers.
Flexible Balanced and Unbalanced Connections
Each of the seven channels includes both a balanced XLR input and an unbalanced RCA input, allowing the MI347 to work with a wide range of surround processors and system configurations. Standard five-way binding posts provide secure speaker connections, while McIntosh Power Control can coordinate startup and shutdown with compatible components.
Multi-color front-panel LED indicators provide a clear view of each channel’s operating status without the space required for traditional power meters.
Protection and Automatic Operation
- Power Guard®: Monitors the audio signal and helps prevent amplifier clipping from damaging connected loudspeakers.
- Sentry Monitor™: Protects the output stages from unsafe current conditions and automatically restores operation when normal conditions return.
- Signal sensing: Can automatically turn the amplifier on when an input signal is detected and shut it down after an extended period without a signal.
- Power Control: Allows compatible McIntosh components to power on and off together.
- Fanless cooling: Efficient amplification and extensive ventilation eliminate the need for potentially noisy cooling fans.
MI347 vs. MC257
The MI347 and the McIntosh MC257 7-Channel Amplifier can both power a complete seven-channel theater, but they are designed around different priorities. The MI347 uses an efficient, rack-friendly Class D design and allocates more power to the three front channels. The larger MC257 uses McIntosh’s traditional solid-state amplifier architecture and provides equal rated power across all seven channels.
The MI347 is particularly attractive for discreet custom installations where rack space, heat management and efficiency are important. The MC257 is better suited to systems where equal high output across every channel and traditional McIntosh amplifier styling are higher priorities.
McIntosh MI347 Specifications
| Amplifier Type | 7-channel digital home theater power amplifier |
|---|---|
| Circuit Configuration | Closed-loop digital switching |
| Front Channel Output | 250 watts x 3 into 8 ohms; 300 watts x 3 into 4 ohms |
| Surround Channel Output | 125 watts x 4 into 8 ohms; 200 watts x 4 into 4 ohms |
| Number of Channels | 7 |
| Total Harmonic Distortion | 0.025% |
| Signal-to-Noise Ratio | 100dB below rated output |
| Dynamic Headroom | 2.5dB at 8 ohms; 3.5dB at 4 ohms |
| Damping Factor | Greater than 85 at 8 ohms; greater than 45 at 4 ohms |
| Frequency Response | +0/-0.9dB from 20Hz to 20kHz |
| Inputs | 7 balanced XLR and 7 unbalanced RCA |
| Speaker Connections | Standard five-way binding posts |
| Rack Height | 3U with removable rack-mounting ears |
| Dimensions | 17-1/2 inches W without ears; 19 inches W with ears x 6-1/16 inches H x 21 inches D |
| Weight | 32.5 lbs |
| Shipping Weight | 47 lbs |
| Heat Output | 1,500 BTU per hour |
| Warranty | 3-year limited warranty |
Frequently Asked Questions
Is the McIntosh MI347 a Class D amplifier?
Yes. The MI347 uses closed-loop digital switching amplifier circuits, commonly described as Class D amplification, to provide high output and efficiency from a compact chassis.
Does the MI347 deliver the same power from every channel?
No. Its three front channels deliver 250 watts into 8 ohms or 300 watts into 4 ohms. Its four surround channels deliver 125 watts into 8 ohms or 200 watts into 4 ohms.
Can the MI347 power a Dolby Atmos system?
It can power seven channels in a Dolby Atmos system. A configuration with more than seven amplified speakers will require an additional power amplifier for the remaining height or surround channels.
Does the MI347 include a surround processor?
No. The MI347 is a dedicated power amplifier and requires an A/V processor or preamplifier, such as the McIntosh MX200, to provide decoding, source switching, volume control and room correction.
Can the MI347 be installed without a rack?
Yes. The included rack ears are removable, so the amplifier can also be placed on a suitably ventilated equipment shelf.
Does the MI347 use cooling fans?
No. Its efficient amplifier design and extensive chassis ventilation allow it to operate without cooling fans.
Authorized McIntosh Dealer Support
Audio Exchange is an authorized McIntosh dealer in Richmond, Virginia. Our team can help evaluate loudspeaker requirements, processor compatibility, rack ventilation, channel planning and system expansion. Browse more components in our McIntosh Home Theater collection or compare additional models in the McIntosh Power Amplifiers collection.
