The A1 was a somewhat controversial amplifier from Musical Fidelity. The electronic design was by Tim de Paravincini. The amplifier was originally launched in 1984, and was in production until the early 90s. Today, it is considered a classic.
The distinctive top cover is used as a heat sink and typically runs at 55-65°C - too hot to touch for more than a few seconds. This is caused by the output stage which is biased with a standing current of around 800mA. If one applies standard analysis, this results in the first 8 watts being delivered in class A - however, the designer argues that things are not quite that simple.
It does have a certain sound that has earned it praise over the years, but whether or not this can be attributed to class-A operation is open to debate. It is undeniably coloured - some reviews draw comparison with valved equipment.
Objectively, compared to its peers, the A1 has a generous power supply, uses some reasonable quality components and is quite well-made. Reliability is a thorny issue; there were no shortage of failures over the years. Facilities are minimal - you get an input selector and a volume control - apart from the power and tape-monitor switches, that's it. Well, apart from a phono stage that could do MC as well as MM. But no other facilities were included - no tone or balance controls, no headphone socket or loudspeaker switching and don't even think about remote control - this was 1984!
