History
Despite the REDD mixing console's involvement in numerous famous recordings of the sixties, it was decided that an outboard equaliser was needed to supplement the limited EQ range on the desk; able to bring presence to the mix and control those frequencies which the REDD could not. The resulting unit, the 127th item made in-house by EMI engineers, was put into service in 1962 and was named the 'RS127 Brilliance Control'.
To begin with, the RS127 was housed in a grey metal box, with a chrome handle so that it could be conveniently rackmounted into the control room patchbays. They became so popular, however, that the Abbey Road engineers would often require two RS127s in series, for a more intensive EQ treatment. To achieve this, a stand-alone portable version, with identical circuits and controls, was built soon after, and painted in the distinctive shade of green seen on much Abbey Road equipment of the time. The RS135 originally operated at 16.4kHz, but was modified to work at 8 kHz to supplement those frequencies provided by the RS127s.
The portability and popularity of these 'Presence Boxes' meant that they were often used throughout the studio complex - not just in the studios themselves, but in the mastering, transfer and post-production rooms as well. Their ease of use and effectiveness at defining individual sounds meant that they became an indispensable tool in most of The Beatles' recording sessions in the latter part of the decade.