McIntosh MHA200

The MHA200 is a tube headphone amplifier designed by McIntosh for discerning listeners who want to get the best from their hifi headphones within a high-fidelity system. It is a dedicated unit, designed to sit between a source and a pair of headphones, with the ability to operate without a preamplifier thanks to its built-in volume potentiometer.

Amplification relies on a pair of 12AT7 dual triode tubes, responsible for amplifying the incoming signal, paired with 12BH7A tubes which deliver the output power. This section is coupled to output transformers of McIntosh's own design, known as Unity Coupled Circuit, whose role is to transfer power from the tube stage to the headphone output without depending on voltage gain at the input. A custom toroidal power transformer supplies the whole unit while limiting mechanical hum and magnetic interference.

The MHA200 offers four impedance ranges selectable via a Load button, each calibrated to deliver 500 mW: 32 to 100 ohms, 100 to 250 ohms, 250 to 600 ohms and 600 to 1000 ohms. Gain varies accordingly, from 12 dB at 32 ohms up to 25 dB at 600 ohms, with total harmonic distortion of 0.5% and a signal-to-noise ratio of 94 dB. Frequency response extends from 20 Hz to 20 kHz. The inputs accept up to 8 V unbalanced and 16 V balanced.

The connectivity covers most high-end headphone configurations:

The MHA200 also features balanced and unbalanced inputs to fit into an existing setup, as well as a Power Control input and output allowing it to be synchronised with other McIntosh units.

This model is aimed at owners of high-end headphones, regardless of their impedance, who are looking for separate tube amplification rather than a simple amplifier built into a sound card or DAC. Its compact size (156 x 146 x 232 mm) allows it to be placed close to the listening position while being connected to the source via long balanced cables without signal loss.