GP Desks - The Mark 4 - described by Mike Chessher

In the Mk 4 desk, extra script space in front of the faders was achieved by removing the cue light keys - foot operated cue lights were much preferred, anyway. The centre modules with monitoring, etc, were moved to the side of the desk. This meant placing the PPMs in a pod on the top of the desk.



3C, above, was the first GP Mk 4 to appear and was well received but clearly illustrates one of the problems with GP. While SMs tended to think of it as a "pick and mix" system, it was very difficult and expensive to keep altering the drawings, so it had to be a standard size carcase with standard wiring. It was just as difficult to remove facilities as add new ones. 3C didn't need 24 channels, so some of the modules were kept as maintainance spares. They were later added as the desk looked odd without them. Note that the PPM pod has been kept as low as possible by cutting away the surounding woodwork.

It is easier to pick out some of the details in these pictures of B15. There are 14 local and 10 outside source channels which can be routed to a choice of 3 groups or IND. The outside source cue modules have buttons to send cue, clean feed and talkback to cue and control lines in any combination with a choice of 4 cue feeds derived from the 4 (green) ringmain selectors below the modules. Next come the telephone ring and answer keys with the prefade/talkback keys below them.

B15, as the main phone-in studio, normally used the last 6 outside source channels for telephone balance units and the indicator lights above the faders are non standard.



The left hand wing of the desk starts with main controls for the aux bus bars, group amplfiers and echo controls. Then comes the monitoring panel with tape remote starts and talkback keys below. The cluster of talkback keys includes 3 auxilaries. AUX 1 has been retained as a totally independent talkback, whilst AUX 2 and 3 are intended for use by presenters and are mastered by studio talkback.

The auxilary (prefade) LS is above the monitoring panel. The row of tone send buttons has grown because "Tone to clean feed" is included and there are 10 of them on this desk. (A facility rarely used in radio and dropped from the later Mk 3 desk.)

To the right is a closer look at a Mark 4 monitoring panel, this one actually is from 5A.

The two rows of white buttons at the top are mono and stereo monitoring selectors, the mono one includes Prefade and Aux outputs, whilst the stereo one has main and group outputs and is used for monitoring off-tape record feeds. (It was normal practice when recording programmes to monitor, or at least spot check, the delayed feed coming from the record machine playback head.)

The main monitoring controls are on the right with volume and balance controls either side of a programme ring main switch, followed by studio and auxilary controls.