Усилители для наушников — McIntosh MHA50

The MHA50 Portable Decoding Amplifier is a smartphone-sized headphone amplifier and DAC built by the New York maker McIntosh. It was announced on 27 September 2017, deliveries started the following month at USD 700, while the UK price was GBP 895. McIntosh lists a production period of 2017 to 2025 and now files it as a legacy product.

Key specs that matter

Headphone output is rated at 200 mW, and the amplifier accepts headphones from 8 to 600 ohms through two gain settings. Harmonic distortion is 0.005%, the signal to noise ratio is 105 dB, and response runs from 20 Hz to 50 kHz within +0 and -0.5 dB, with a rated power band of 20 Hz to 20 kHz. A 32-bit DAC decodes PCM at 16, 24 and 32 bits up to 192 kHz from the USB input, plus DSD64, DSD128 and DXD at 352.8 and 384 kHz. Bluetooth A2DP carries AAC and aptX. The line level from the 3.5 mm socket reaches 1.8 V. A 3,000 mAh rechargeable battery gives up to 6 hours with Bluetooth and longer over a wired link, and charging runs from 5 V DC at 0.7 A. The body is about 7 x 15 x 1 cm and weighs 200 g.

Engineering and use context

The case is extruded aluminium with a glass front, and volume is set by a touch-sensitive control styled after the round knob of McIntosh home components. USB audio runs in asynchronous mode. Two USB ports are provided - a Type A socket and a micro B socket - and adapter cables in the box cover Apple iOS devices, Android handsets that support USB On-The-Go, and Mac or Windows computers. The Headphone Crossfeed Director, which McIntosh calls HXD, works on the headphone output. A leather carry case and a multi-region wall charger are also supplied, and the warranty runs 3 years. Power comes from the internal cell, so the amplifier is not tied to a wall socket during use, and the unit is classed as solid state. Streaming apps on a phone reach it over Bluetooth, while stored hi-res files are best sent through the USB path.

Pairing

The gold-plated line output can also feed powered desktop speakers, which turns the unit into a compact DAC for a computer desk. The two gain positions split the supported impedance window between sensitive low impedance earphones and full-size headphones of higher impedance. Phones and tablets without a USB audio path can still connect over Bluetooth.

Alternatives

The McIntosh MHA200 is a mains-powered desktop headphone amplifier with 12AT7 and 12BH7A tubes, Unity Coupled Circuit output transformers and a 500 mW rating.