The Deacy Amp (pronounced "Deeky") is an electric guitar amplifier created in 1972 by Queen's bass guitarist John Deacon, who was an electronic engineer by training. The amplifier circuit board from a Supersonic PR80 portable radio found in the trash was fitted into a speaker cabinet and powered by a 9-volt battery. The amplifier had no volume or tone controls and for most of its history it was never broken thus never repaired. It was used along with Brian May's Red Special electric guitar and treble-booster to produce sounds reminiscent of various orchestral instruments, such as violin, cello, trombone, clarinet, or even vocals, starting from the songs "Mad The Swine" an unreleased song from the 1973 album Queen and "Procession" from the 1974 album Queen II.
KAT Deacy Amp replica
In 1998, Greg Fryer undertook the job of trying to make three copies of the Deacy Amp with May's full backing with the help of UK amp specialist Dave Petersen. These amps produced a similar compressed and saturated sound but lacked the tonal characteristics that were so crucial to the unique Deacy sound. In 2003, Nigel Knight became involved in the amp's development. Several prototype amps were built that were continually edging closer to the sound of the original but all fell short of the mark when compared side by side with the real amp. It was only in 2008 when Knight was given permission to take the original Deacy Amp apart and test and analyse each individual component that he finally began to understand the intricate workings.
With this new information in hand, Knight called on speaker manufacturers Celestion, who developed and produced nearly 30 prototypes for testing and analysis over a two-year period. Custom transformers were produced to exact winding and laminate specs, obsolete components were sourced and made RoHS compliant and bespoke cabinets were constructed from Sapele veneered chipboard, exactly as the original.
The first production run of KAT Deacy Amp replicas were shipped in March 2011 and sold out within one month. Production of the KAT Deacy Amp was later discontinued.