McIntosh MI128 8-Channel Digital Power Amplifier
The McIntosh MI128 is a compact, high-performance 8-channel amplifier designed for distributed audio, multi-zone music systems, home theater expansion and flexible stereo installations. Its closed-loop Class D amplification delivers 120 watts per channel into 8 ohms or 150 watts per channel into 4 ohms, giving custom-installed systems substantial output from a fanless 2U chassis.
With eight independently controlled channels, bussable analog and digital inputs, channel summing and installer-friendly Phoenix speaker terminals, the MI128 can power multiple rooms, additional home-theater channels or several stereo speaker pairs from one amplifier.
Eight Channels for Multi-Zone and Home Theater Systems
The MI128 is particularly well suited to whole-home and distributed audio. Eight amplifier channels can support up to four stereo zones when configured as stereo pairs, while channel summing makes it easy to distribute mono audio where stereo playback is unnecessary. Individual channel inputs and volume controls allow each output to be balanced for the connected room and loudspeaker.
It can also serve as a home-theater expansion amplifier for surround, height or additional zone speakers. Pair it with the McIntosh MX200 A/V Processor when more channels are needed, or use it alongside the McIntosh MC257 7-Channel Amplifier to add power for secondary surround and overhead channels.
120 Watts per Channel into 8 Ohms
Each of the MI128’s eight channels produces 120 watts into an 8-ohm loudspeaker or 150 watts into a 4-ohm loudspeaker. The direct-coupled output stage and robust power supplies are engineered to maintain consistent performance across all channels while preserving the compact dimensions needed for equipment-rack installation.
Efficient Closed-Loop Class D Design
The MI128 uses sophisticated closed-loop digital switching amplification. Its efficient Class D architecture produces less heat than a conventional multi-channel amplifier and does not require cooling fans, helping it remain quiet in listening rooms, media closets and centralized equipment racks.
Bussable Analog and Digital Inputs
Each channel has an individual unbalanced RCA input, while BUS inputs and outputs make it possible to distribute a stereo signal across multiple channel pairs or additional amplifiers. Two digital audio inputs accept either coaxial or optical connections and can also be assigned through the amplifier’s bussing system.
Rear-panel switches provide local or BUS input selection and stereo or mono operation for each channel pair. Separate level controls allow installers to balance the output of individual channels without adding external attenuators.
Installer-Friendly Connections
The rear panel uses compact 2-pole Phoenix-style push-in speaker terminals, conserving space while providing secure connections for all eight channels. Twelve-volt triggering integrates the MI128 with compatible control systems and McIntosh components, while automatic signal sensing can turn the amplifier on when audio is detected and place it into standby after a period without a signal.
McIntosh Speaker Protection
- Power Guard®: Monitors the audio signal and helps prevent harsh clipping that could damage connected loudspeakers.
- Sentry Monitor™: Protects the output stage from short circuits and unsafe current levels, then automatically resets when normal conditions return.
- Multi-color channel indicators: Eight front-panel LEDs show each channel’s operating and protection status.
Compact 2U Rack-Mount Chassis
The MI128 is only 2U high and includes removable rack-mounting ears. It can be installed in a standard 19-inch equipment rack or used as a conventional component with the ears removed. The black glass front panel, illuminated McIntosh logo and silver trim maintain the company’s signature appearance even in its streamlined custom-install format.
MI128 vs. a Traditional Home Theater Amplifier
The MI128 prioritizes channel count, flexible signal distribution and rack efficiency. It is an excellent choice for distributed audio, Atmos height channels and secondary home-theater speakers. For the main channels of a demanding theater, a higher-powered amplifier such as the MC257 may provide greater output and traditional speaker connections. Many systems use the two types together: a larger amplifier for the front and primary surround channels, and the MI128 for additional channels or music zones.
The McIntosh MHT300 Home Theater Receiver can also be expanded with external amplification when a system requires additional channels beyond its internal amplifier section.
McIntosh MI128 Specifications
| Amplifier Type | 8-channel digital Class D power amplifier |
|---|---|
| Power Output per Channel | 120 watts into 8 ohms; 150 watts into 4 ohms |
| Number of Channels | 8 |
| Total Harmonic Distortion | 0.05% |
| Signal-to-Noise Ratio | 95dB below rated output |
| Dynamic Headroom | 2.1dB at 8 ohms; 3.3dB at 4 ohms |
| Damping Factor | Greater than 65 at 8 ohms; greater than 32 at 4 ohms |
| Rated Power Band | 20Hz to 20kHz |
| Frequency Response | +0/-0.5dB from 20Hz to 20kHz |
| Circuit Configuration | Closed-loop digital switching |
| Output Type | Direct coupled |
| Analog Inputs | Individual unbalanced RCA inputs with BUS input and output |
| Digital Inputs | 2, selectable coaxial or optical |
| Speaker Connections | 2-pole Phoenix-style push-in terminals |
| Channel Controls | Individual volume controls; local/BUS and stereo/mono selection |
| Power Control | 12-volt trigger and automatic signal sensing |
| Cooling | Fanless |
| Rack Mounting | 2U with removable rack ears |
| Dimensions | 17-1/2 inches W without ears / 19 inches W with ears x 4-5/16 inches H x 21 inches D |
| Unit Weight | 22 lbs |
| Shipping Weight | 38.4 lbs |
| Warranty | 3-year limited warranty |
Frequently Asked Questions
How many rooms can the McIntosh MI128 power?
The eight channels can be arranged as four stereo pairs, making the MI128 suitable for powering up to four conventional stereo zones. Other combinations are possible depending on whether individual areas use stereo or summed mono playback.
Can the MI128 be used for Dolby Atmos speakers?
Yes. It can power additional surround or height channels when connected to a compatible A/V processor with unbalanced preamplifier outputs.
Does the MI128 have balanced XLR inputs?
No. The MI128 uses individual unbalanced RCA inputs, BUS inputs and digital coaxial or optical inputs.
Can the MI128 be bridged for more power?
No. The amplifier does not support mono bridging or parallel channel operation. Each channel is rated independently at 120 watts into 8 ohms or 150 watts into 4 ohms.
Does the MI128 require a cooling fan?
No. Its efficient Class D design is fanless, helping it operate quietly in a listening room or equipment rack.
Are rack ears included?
Yes. The MI128 includes removable rack-mounting ears for installation in a standard 19-inch rack.
Authorized McIntosh Dealer Support
Audio Exchange is an authorized McIntosh dealer in Richmond, Virginia. Our team can help determine channel requirements, speaker compatibility, control-system integration and rack-planning needs for distributed audio and home-theater installations. Explore more options in our McIntosh Power Amplifiers and McIntosh Home Theater collections.
