Roger Mayer is a British electronics engineer and effects pedal pioneer who has been designing and building guitar effects and studio equipment since 1964. Originally an acoustic engineer working for the British Admiralty on underwater research, Mayer began crafting custom fuzz boxes for leading guitarists of the London scene, including Big Jim Sullivan, Jimmy Page, and Jeff Beck. His place in music history was cemented when he met Jimi Hendrix in January 1967 and built the Octavia — an octave-up fuzz pedal that Hendrix used on the guitar solo of "Purple Haze" just weeks later. Mayer went on to serve as Hendrix's personal effects technician, designing and modifying gear throughout the guitarist's career.

The Octavia remains one of the most iconic effects pedals ever made, and Mayer continues to produce updated versions alongside an extensive lineup of effects and studio equipment, all handbuilt in the UK. His guitar pedal range includes the Purple Haze Octavia, Voodoo-Vibe+, Classic Fuzz, Voodoo-1, Voodoo-Bass, Voodoo-Axe, Concorde+, and the Rocket series (Rocket Octavia, Rocket Axis, Rocket Spitfire, Rocket Visage). On the studio side, he produces the 456HD analog tape simulation processor, the RM 58 Classic Stereo Limiter, microphone preamps, and active direct interfaces.

Widely regarded as the world's first boutique pedal builder, Mayer's effects have been used by an extraordinary roster of guitarists spanning decades, including Jeff Beck, Jimmy Page, Stevie Ray Vaughan, David Gilmour, Eric Johnson, Joe Bonamassa, Noel Gallagher, Johnny Marr, and John Squire. He received the Vintage Guitar magazine Innovator of the Year Award in 2018 and was nominated for a Technical Grammy in 2000.

Roger Mayer has 49 products cataloged on Equipboard, including Fuzz Effects Pedals, Overdrive Effects Pedals, and Univibe & Rotary Effects Pedals. Their gear is featured by 75 artists, with the strongest followings in Rock, Pop, and Blues. Notable users include Chad Taylor, Kevin Shields, and Sergio Pizzorno. Most Roger Mayer products sit firmly in the high-end, boutique range.