Integrated amplifiers — McIntosh MA352

McIntosh's MA352 is a hybrid integrated that pairs a valve preamplifier with a solid-state power amplifier in one all-analogue chassis. It replaced an earlier McIntosh hybrid and doubles that model's output power. The casework follows the brand's familiar look - a polished stainless-steel chassis, a glass front panel with blue watt meters and die-cast aluminium name badges on both sides.

Key specs that matter

The preamplifier stage uses two 12AX7A and two 12AT7 valves and drives a direct-coupled solid-state output stage rated at 200W per channel into 8 ohms and 320W per channel into 4 ohms. There are two balanced line inputs, three unbalanced ones and a moving-magnet phono input. For outputs the MA352 has a stereo preamplifier output, a variable unbalanced output and a High Drive headphone amplifier, and loudspeakers connect to gold-plated binding posts. The chassis measures about 44.5 x 25.1 x 44.3cm, and the amplifier weighs just under 30kg.

Engineering and use context

In this hybrid layout the valves work only at small signal voltages in the preamplifier, while transistors supply the high current the loudspeakers draw. Valve wear is therefore confined to the low-level stage, and the output stage needs no output transformers. Many larger McIntosh amplifiers have output autoformers, but the MA352 does not, so its power rises from 8 to 4 ohms rather than staying the same. Several McIntosh protection circuits are fitted. Power Guard watches the output for overdrive and corrects the input signal on the fly so that clipping cannot harm the speakers. Sentry Monitor is a fuseless short-circuit protection that switches off the output stage before current reaches unsafe levels and resets itself automatically. The high-current output transistors sit on McIntosh Monogrammed Heatsinks, designed to shorten thermal warm-up time. The dual-scale watt meters show output power for both 8 and 4 ohm loads, and the headphone stage includes the McIntosh Headphone Crossfeed Director (HXD) circuit.

Pairing

The MA352 drives most passive loudspeakers on its own, without an external power amplifier. Its preamplifier output can later feed a larger power amplifier or one or two powered subwoofers. Home Theater Pass Through allows an AV processor to use the same speakers in a cinema system, and the Power Control and Data Ports switch and control other McIntosh components. The built-in MM phono stage accepts a turntable without any extra box.

Alternatives

The McIntosh MA8950 is a solid-state integrated amplifier with output autoformers and a built-in DAC, giving digital inputs and the same power into any speaker impedance.