The basic premise behind May’s monstrous tone comprises two separate stages of signal boost in front of the amp. The first comes from his unique guitar, which allows for the combination of up to three single-coils in series, rather than parallel. The signal then runs to a treble booster, more recently built by Greg Fryer. May used Vox AC30s even before Queen were formed and this double-boosted signal is fed into amps that are run at absolutely full volume.
The solo from Play The Game is a lesser-known yet perfect example of the aural results of this unusual set-up: only the songs Crazy Little Thing Called Love and Long Away (from 1976’s A Day At The Races) from the Queen canon are bereft of the classic set-up.