Deacon's first bass, used in The Opposition, was an Eko, later switching to a Rickenbacker 4001. For most of Queen's career, he used a Fender Precision Bass, which underwent a number of cosmetic changes. Towards the end of the group's career, he used a custom bass designed by Roger Giffin. He also used an Ernie Ball MusicMan Stingray live on occasion. As a trained electronics engineer, he was able to build equipment for the band. His most famous creation is the "Deacy Amp", built in 1972 from pieces of electronic equipment found in a skip, and used by himself and May throughout Queen's recording career. Many of the so-called "guitar orchestras" on Queen albums use this amplifier.