The correct name for this is 'the FM tuner', although it is often known as the FM1. This is part of the Quad II/22 setup, needing to be powered by the 22 control unit or a separate 330VDC supply. When well-aligned, it is a very serious audiophile contender among valve FM tuners. There are four or five circuit variations, depending on serial number, including valve changes. The original factory 'bird-cage' decoder is now of historical interest only, and should generally be replaced with a modern unit. However we can certainly align and renovate this original MPX unit, which will substantially improve the sound.