This is worst-case USB: I fed a 7-way Belkin hub from my MacPro, and then ran a 6 foot crappy USB cable to the DacMagic Plus, for a total of about 12 feet of 10-year-old USB cable. It always stays on, so if fed from a Mac, there are no power thumps since it's always on. If my Mac is sleeping and I turn on the DacMagic connected by USB, my Mac wakes.

Hmm, 0.2% distortion isn't good, but probably not audible. The Benchmark DAC1 HDR is much, much better here if you want a great, accurate headphone amplifier and DAC. Move on to Emeli Sandé’s Heaven and the Cambridge paints a tonally even picture with well-mannered treble and weighty, precise low frequencies. It turns and turns without stops. You never really know where the volume's set, except that the source LED blinks when you're all the way up or down.

USB audio connection

But you have to pay for it, and with impressive competition, the DacMagic Plus is in 'very good' (but not class-leading) territory.

The DacMagic Plus is a lightweight piece of consumer equipment that is sonically superb, although the slowly-responding volume control and its plastic knob is a real disappointment. It only has digital inputs so it's not really a preamp, but it does have four selectable inputs, a volume control and even a headphone output, so for many of us, it can be our master control center.The Cambridge Audio DacMagic is practical and good-looking too and we would rate it all-round as one of the best audio bargains we've come across in a while. Switch to the USB connection and Amy Winehouse's Valerie ('68 version) from the Lioness: Hidden Treasures album, there's not the weight or refinement we get from our reference Arcam rDAC. The Cambridge Audio DacMagic Plus is the most linear DAC I've ever tested, better than the Benchmark DAC1 HDR. Power: 12V wall-wart. 100-240V, 50-60 Hz, with three different power connectors for world-wide use.