BC1 Small Format Broadcast Consoles

Playback - Talkback Module

The Master Status Section displays the state of the main control busses MIC On and LINE On. The ON-AIR control can be coupled to any combination of these busses by internal jumpers. In additional the ON-AIR switch allows to set ON-AIR mode by hand. A relay contact that is available on the remote connector makes the control of external equipment possible. The MIC switch is actually a user switch that drives a second relay that is also available on the remote connector. It is always controlled by the switch and can be coupled to any of the busses or to a console internal control function by jumpers. Custom engraved lettering of these switches is possible, of course. 

The logic control block contains the AutoDim control, the AutoCut control, the On-Air Control and the Mic On and Line On busses. The default configuration connects the Mic On busses to the Mic output and the AutoCut circuitry, while the wired or of the  On-Air switch, the Line On and the Mic On bus drives the On-Air output. With this configuration, the microphone red light is controlled by the mic output while the 'Silence' light is controlled by the On-Air function.

The AutoCut control can mute the studio speakers and the control room speakers. The mute for the particular system can be selected by switches next to the cut switches individually. This makes possible to use the console for broadcasting with a separate studio and for so called 'DJ-mode' where the disk jockey in the control room is the moderator as well without the need of changing anything else but the position of the autocut switches.

The Studio Playback Section has an independent sources selector with a switch block of five mutually released switches. These switches makes possible to select the auxiliary sends Aux1 to Aux4 and the program master MIX. Actually, this selector is a fixed level mixer that allows pressing more than one button at a time and adding the selected sources to build a playback signal out of several sources.

The output of the source mixer drives the independent control sections for studio speakers and studio headphones. Each section has a talkback circuit with a talkback level control and a switch to enable Talkback STUDIO for the particular output section. With talkback on, the playback signal is attenuated by 20 dB. The DIM switches can be coupled to the AutoDim bus by jumpers. DIM causes a 20 dB attenuation that is independent of the talkback DIM. Both values can be adjusted to meet the local requirements by changing the values of two resistors per circuit. This principle makes sure, that no feedback occurs with Intercom mode, where both, outgoing and incoming talkback, is active at a time.

The level of the playback outputs is controlled by separate rotary pots. The output amplifier of the headphone section can drive up to 3 headphones in parallel. However, the headphones should have the same impedance. A TRS jack on the top plates allows direct connection of a headphone. In addition, the output is available on the connector panel. The speakers output has a cut switch that mutes the studio speakers manually and an additional switch that enables AutoCut. In standard configuration with AutoCut pressed, the studio speaker will be muted as soon as at least one microphone fader is open. The studio speakers output drivers are electronically balanced and operate at nominal level.

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IM - Mono Module
IS - Stereo Module
IT - TelCo Module
SG - Group Module
PG - Master Module
CT - Monitor Module
TB - Playback/Talkback
Block Diagram
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Top Plate View - PDF

Playback - Talkback Module TB