Усилители мощности стерео — McIntosh MI128

The McIntosh MI128 is an eight-channel digital power amplifier intended for distributed audio, home theater and stereo duties. Each of its eight channels is driven by a closed loop digital switching amplifier fed from a heavy-duty power supply, and the chassis is built as a 2U unit that fits a standard equipment rack. McIntosh covers the model with a 3-year limited warranty.

Key specs that matter

Every channel delivers 120 W into 8 ohms or 150 W into 4 ohms across a rated power band of 20 Hz to 20 kHz, and the FTC rating is 120 W. Total harmonic distortion is 0.05 percent, and noise sits 95 dB below rated output. Headroom for short peaks amounts to 2.1 dB into 8 ohms and 3.3 dB into 4 ohms. The damping factor is above 65 into 8 ohms and above 32 into 4 ohms. Frequency response is held within +0 and -0.5 dB from 20 Hz to 20 kHz. Output is direct coupled. The unit measures 44.45 x 11 x 53.3 cm and weighs 10 kg, with a shipping weight of 17.4 kg, and McIntosh gives a heat output of 1000 BTU/h.

Engineering and use context

Because the amplifier works in Class D, it runs without cooling fans. The glass front panel carries a multi-color LED indicator for each channel lit directly by LEDs, set on a steel chassis painted black. Rack ears can be removed when the amplifier stands on a shelf instead of in a rack. On the rear panel every channel has its own unbalanced input and its own volume control, and speakers attach through 2-pole Phoenix-style terminals. BUS inputs and outputs let one signal be shared across channels or passed on to further amplifiers. Power Guard watches for signal overload, while Sentry Monitor protects the outputs against short circuits. A 12-volt trigger input and an on/off signal sensing function allow the MI128 to switch itself on when a source starts playing and back off when the signal stops, which suits installations where the amplifier sits out of sight.

Pairing

With eight independent channels and per-channel level controls, one MI128 can feed four stereo zones of a whole-house system, or cover the speakers of a surround layout from a processor. Its 4 ohm rating allows use with in-ceiling and in-wall speakers of lower impedance, and the Phoenix-style terminals match the bare wire runs common in such installations.

Alternatives

The McIntosh MI502 is a two-channel model from the same digital range, with far higher output per channel.