Усилители мощности стерео — Chord ALTO

The Alto from Chord Electronics is a compact two-channel amplifier that drives both loudspeakers and headphones, designed and handmade in the UK. It followed the Ultima Pro Mono, rated at 1 kW, and the Ultima Pro Stereo models, and it carries the same Ultima circuit topology in a 1U casing built for 19-inch racks with a footprint barely larger than an A5 sheet. It was priced at GBP 2,150 and comes in black.

Key specs that matter

Speaker output is 50 W into 4 ohm at 0.003% THD, and the maximum output voltage is 15 V RMS into 8 ohm. The headphone section delivers 2,250 mW into 100 ohm at 0.001% THD. Noise sits 120 dB below full output, and Chord quotes a frequency response of 6 Hz to 60 kHz, crosstalk of -95 dB and a maximum input level of 6 V RMS. For the source signal there is one stereo pair of balanced XLR and one stereo pair of RCA. At the back are banana sockets for one pair of speakers, a pair of XLR outputs for passing the volume-controlled signal on, and a 12 V DC jack. The front holds four headphone sockets - one 3.5 mm, one balanced 4.4 mm Pentaconn and two 6.35 mm. The case measures 215 mm long, 200 mm wide and 57 mm high and weighs 1,946 g.

Engineering and use context

The Ultima topology uses dual feed-forward error correction, which monitors the signal and corrects it before it reaches the output stage. Power comes from ultra-high-frequency supplies of Chord's own design, the same approach used in its larger amplifiers, and the input accepts 80 to 250 V AC with automatic switching. The casework is machined from aircraft-grade aluminium and locally anodised. Since all four headphone outputs can be used at the same moment, the Alto can feed up to four pairs of headphones in a studio or listening session, while the speaker terminals cover close-field monitoring. Chord gives a 3-year warranty.

Pairing

With its moderate power, the Alto fits compact close-field monitors and small passive bookshelf speakers in a room up to about 20 m2 rather than large, low-efficiency towers. A DAC or preamplifier with balanced outputs can feed the XLR inputs, and the XLR pass-through allows a pair of active monitors or a second amplifier to share the same volume setting.

Alternatives

The Chord Étude is a compact class A/B stereo power amplifier that Chord rates at 150 W.