8th Floor - Control Room 1 - Broadcasting House in 1932



The Control Room at this time did actually control the outputs of microphones in the studios. One man could sit at a control position here and control all the studios in the building.

above - The near end of the room contained the six control desks used for transmissions, in two groups of three. Between them are the simultaneous broadcasting and supervisory positions. The former routed the programmes passing through the control positions to any of the outgoing lines. The supervisory position provided monitoring facilities and acted as the central exchange for the Control Room telephone system. On the left were the racks of amplifiers and other equipment.

At the far end, beyond the final beam and better seen in the photo, right, were eight desks used for rehearsals.

One of the fade units

left -
A four-channel fade unit at one of the control positions. The two outer faders each controlled two sources, cross-fading between them. The central fader combined the outputs of the outer ones in the same way and the output of that fader was fed to the main control, lower left. See the next page for more information about the operation of these desks and the technical section for more details.

Although the meter looks like today's Peak Programme Meter, it isn't one. The PPM was not developed till about 1936 or 7 but it did retain the previously designed scale.

Check Receivers

right -
Cables in the false floor, ending on terminal strips at the bottom of the 'A' amplifier bays and connecting them with the studios. High output, low impedance Microphones were connected directly to the Control Room through a balanced, screened pair. The cable, which could be up to 1000 feet long, connected through a step-up transformer to an 'A', or microphone, amplifier. High impedance microphones, such as condenser mics, needed a pre-amplifier in the studio, the required power being fed down the microphone cable. The power supply was by means of batteries, in duplicate throughout. The battery room was on the sixth floor.

above - Part of one of the relay bays, showing three types of relay used in amplifier switching.

left - Two of the receivers used for checking the quality of transmissions.

Cabling

	left - Two of the 'B' amplifier bays. The covers have been removed from a 'B' amp near the top of the bay, and from a programme meter amplifier near the bottom.
	right - The reverse of the 'B' amplifier input switching relays bays. (See next picture.)

The 'B' amplifier input switching relays.

	left - One of the fuse bays.
	right - The back of the power board, showing the massive low tension busbars supported on the insulators.

In addition to the material on this and the next page, there is more information about the Control Room in the technical section.



Plan \| Control Room - 1 \| Control Room - 2 \| Studio 8A \| 8B & Drama Control \| Misc Areas Top of Page \| Old Radio Broadcasting Equipment Main Menu