McIntosh MC303AC 3-channel surround power amp

MC303 AV 3-channel power amplifier

The McIntosh MC303 AC is an uncompromising 3-channel power amplifier for demanding home theater and high-end setups. Delivering 300 watts per channel, it provides identical power to the front left, front right, and center channels – even when all three channels are driven at full power simultaneously. As the company's first multi-channel amplifier with Output Autoformer™, it delivers its full rated power regardless of speaker impedance at 2, 4, or 8 ohms – a crucial advantage for maximum speaker freedom and consistent performance.

The MC303 AC combines enormous power reserves with exceptionally low distortion. With a maximum total harmonic distortion of 0.005% across the entire audio band from 20 Hz to 20 kHz, the sound remains stable, clean, and controlled even at high volume levels. A dynamic headroom of 1.8 dB ensures additional composure during transient peaks.

The exclusive McIntosh power protection system safeguards both amplifiers and speakers. Power Guard® continuously monitors the input and output signals, preventing clipping through controlled level adjustment. Sentry Monitor™ acts as a fuseless short-circuit protection circuit and resets automatically. The legendary blue wattmeters respond quickly and accurately to program peaks, providing immediate control over the output power – and can be switched off for home theater use.

With 60 amps of output current, generously sized gold-plated five-way speaker terminals, and a robust power supply, the MC303 AC is perfectly equipped for even the most demanding loudspeakers. Visually, it features classic McIntosh aesthetics: a thick glass front, illuminated wattmeters, anodized aluminum handles, and a mirror-polished stainless steel chassis.

Technical specifications of the MC303 AC:

Output power
300 watts per channel into 2 ohms, 4 ohms or 8 ohms
(minimal continuous sine wave power, all channels operating simultaneously)

Output load impedance
2 ohms, 4 ohms, 8 ohms

Nominal power band
20 Hz to 20,000 Hz

Frequency response
0 / -0.25 dB from 20 Hz to 20,000 Hz
+0 / -3 dB from 10 Hz to 100,000 Hz

Total harmonic distortion (THD)
Maximum 0.005% of 250 mW up to the rated power
(20 Hz to 20,000 Hz)

Intermodulation distortion
Maximum 0.005% for instantaneous peaks up to twice the rated power

Dynamic control reserve
1.8 dB

Signal-to-noise ratio (A-weighted)
112 dB below nominal output

Broadband attenuation factor

40

Input sensitivity for nominal output
1.7 V asymmetrical
3.4 V symmetrical

Input impedance
10,000 ohms

Output current
60 A

Power Guard
< 2% THD at a maximum of 14 dB overdrive at 1,000 Hz

Power Control
Input: 5–12 V DC
Output: 12 V DC, max. 25 mA, delay 0.2 s

Power consumption
240 V, 50/60 Hz at 6 A
Standby < 1 W

Dimensions (W × H × D)
45.09cm × 31.4cm × 55.9cm

Weight
70.3 kg net
81.6 kg including packaging

The MC303 AC is therefore a powerful, load-stable and sonically neutral power amplifier that particularly shines in high-quality home cinema environments – with the typical sovereignty, reliability and quality of McIntosh.