Abbey Road Studios engineers found the presence boxes excellent for guitars, vocals and drums, especially snare and kick drum direct to tape. The units were in constant operation throughout the studios during recording and mixing, used to define the sound of instruments, brighten up the feed to the echo chambers and patch over compressors to create de-essers. They even found their way into the cutting rooms.
The original equalizers were exclusively built in-house by the Abbey Road engineers in the 1960s and quickly became a secret weapon at the studios. Before the plug-in version was released, they had never been available outside of Abbey Road Studios. Softube has faithfully modelled the passive circuitry of the three original units, component by component.