Type A was the first mains powered self-contained equipment to be specifically
designed for use in BBC studios. Unlike today, there were no commercial manufacturers
designing and building broadcast equipment in Britain, so it had to be designed
'in-house'.
During the war considerable use was made of outside broadcast equipment both
in studios and control rooms and much of it was still in use in 1960. A 16-input
desk could be quickly wired up using 4 MX/18 mixers and an OBA/8 amplifier.
This equipment appears to have made redundant the Dramatic Control Panels
that had been used not only for drama but also for other large and complex
productions that could not be accommodated by the simple desks in pre-war
studios. Dramatic Control Panels were designed to operate in conjunction with
1932-style control rooms and could be looked upon as the predecessors of modern
studio desk, but by the end of the war they had disappeared without trace
and little is known about how they were used for non-drama productions.
In 1943/1944 work started on designing post-war studio equipment. It was to
have the amplifiers in the studio itself, not in the control room and the
output from the studio would be at zero level like OBA/8 equipment not at
-70dB as in the pre-war equipment.
The pre-production model Type A desk
(right) was installed in Studio
8A in Broadcasting House, London and handed over to the Engineer-in-Charge
of London Station on 11 December 1944 but it was March 1946 before the production
models appeared.
There were two basic forms of the Type A desk, the Mark II with 5 channels
(the picture,
right, shows one in Studio 4A in 1947)....
....and the Mark V with 7 channels (
above) or sometimes nine (
right).
Assuming the first pre-production model was Mark I, it is a mystery what happened
to Marks III and IV. There was a desk with 12 channels in one of the long
defunct outside studios, Piccadilly Studio 1, which one source refers to as
a Mark VII desk.
