Integrated amplifiers — McIntosh MA352

The MA352 is a hybrid integrated amplifier from McIntosh that combines a vacuum tube preamplifier with a solid-state power amplifier in a single all-analogue chassis. It succeeded an earlier hybrid McIntosh model with double that model's output power, and is built on the brand's polished stainless-steel chassis with the familiar glass front panel, blue watt meters and die-cast aluminium name badges on each side.

Key specs that matter

The preamplifier section runs on a pair of 12AX7A and a pair of 12AT7 vacuum tubes, feeding a direct-coupled solid-state output stage rated at 200W per channel into 8 ohms and 320W per channel into 4 ohms. Inputs comprise two balanced, three unbalanced and one moving-magnet phono input. Outputs include a stereo preamplifier output, a variable unbalanced output and a High Drive headphone amplifier, with gold-plated speaker binding posts. The chassis measures about 44.5 x 25.1 x 44.3cm and weighs just under 30kg.

Engineering and use context

The hybrid layout places the tubes where they handle only small signal voltages in the preamplifier, while transistors deliver the high current the speakers need, so tube wear is limited to the low-level stage and the output does not depend on output transformers. Unlike many larger McIntosh amplifiers, the MA352 has no output autoformers, which explains why power rises from 8 to 4 ohms instead of staying constant. Several McIntosh protection systems are built in. Power Guard monitors the output for overdriving and makes real-time adjustments to the input signal to prevent clipping that could damage speakers, and Sentry Monitor is a fuseless short-circuit protection that disengages the output stage before current exceeds safe levels, then resets automatically. The high-current output transistors are mounted on McIntosh Monogrammed Heatsinks designed to shorten thermal warm-up time. The dual-scale watt meters read output power for both 8 and 4 ohm loads, and the headphone stage includes McIntosh's Headphone Crossfeed Director (HXD) circuit.

Pairing

With 200W into 8 ohms and 320W into 4 ohms, the MA352 drives the great majority of passive loudspeakers without an external power amplifier. The preamplifier output can feed a larger power amplifier later or connect one or two powered subwoofers. Home Theater Pass Through integrates it with an AV processor for shared use in a cinema system, while Power Control and Data Ports switch and command other McIntosh components. The phono input covers a moving-magnet turntable directly.

Alternatives

McIntosh's own MA8950 is a solid-state integrated amplifier with output autoformers and a built-in DAC for buyers who want digital inputs and constant power into any speaker impedance.