BSM designed a new private stock Booster

Furthermore the unit was designed to get this sound from any stock "Bright" input found on classic Marshall amps The story goes that Blackmore recorded the first songs on the road using different studios and without his personalised Marshall Major amps; just his guitar and the AIWA reel-to-reel with the studio's own Marshall amps. Ritchie used Purple's support act "Elf" (with Dio) as backing band and kept the recordings secretly away from his employing band.