Musical Fidelity has a long history of making superlative headphone amplifiers. The M1 HPA pure Class A headphone amp has exactly the same sonic characteristics with headphones as our pure Class A amplifiers with loudspeakers. The M1 HPA pure Class A headphone amp's technical performance is outstanding. Distortion is incredibly low (less than .0005% across the band) frequency response is ruler flat. Noise ratio is outstanding. In every technical parameter the M1 pure Class A headphone amp is outstanding.
The HPA has very low output impedance (below 1 ohm). Headphone amps' output impedance is a usually ignored but very important measurement. The HPA's extraordinary low output impedance means that it can drive any headphone with complete linearity and low distortion. The vast majority of competitive headphone amplifiers cannot do this because they have much higher output impedance.
The HPA has two inputs; line and USB (from computers etc.). It has two headphone sockets on the front panel and a loop out facility. Importantly the HPA also has a variable line output so that it can be used as a very high quality, simple preamp.