Headphones

While the ‘High’ and ‘Low’ toggle on the left of the M1’s fascia seems to have no effect on gain via either its RCA or 3.5mm SE headphone outputs (+5.75dB or just under x2), the 4.9V maximum output is very close to Dethonray’s 5V specification. In practice this translates into 40mW driving high impedance (600ohm) in-ears and 656mW/32ohm before lifting to a healthy 1.25W/8ohm. This is far better than Dethonray itself imagines, rating the M1 at just 230mW/32ohm, while the wide 100.5dB A-wtd S/N ratio and very low –100dBV (10µV) residual noise ensure the headphone amp will deliver very quiet backgrounds, at least via the analogue input where any ‘digital’ interference is blessedly absent. Some variation into low/variable impedance ’phones will be caused by the 1.8ohm source impedance (0.4dB/32ohm, for example) but the M1’s response is otherwise gently rolled off at high frequencies, falling to –1.2dB/20kHz and –9.6dB/100kHz. Distortion is only mildly influenced by headphone load – performing at its best into 32ohm – but is more influenced by frequency, increasing from 0.003%/200Hz to 0.009%/2kHz and 0.03%/20kHz at 1mW/32ohm. This, clearly, is the M1’s ‘sweet spot’.