BC1 Small Format Broadcast Consoles

Stereo Sub Group Module

The BC1-SG is the stereo subgroup master module of the small format broadcast console system BC1. The installation of sub group modules is optional. The consoles are fully functional and the subgroups add just the group feature. The BC1-SG can be used in any possible combination with the group master feature that is implemented with the mono input module BC1-IM. Of course, it is not possible to use one of the existing bus rails for two group master sections at a time. The assignment of group rails to group master modules is made by bridges in the console frame. Any module slot can be configured to be the master for any desired subgroup. Since all input modules and the subgroup master module as well use the same connector set, this configuration can be changed by altering the connections in the frame at any time.

The device contains an ultra low noise stereo bus amp, a electronically balanced, switched stereo insert section, a 100 mm conductive plastic stereo fader, a routing section that makes 'deep groups' possible and a stereo group output amplifiers.

The Bus Amp Section contains a stereo summing amplifiers that is optimized for best noise performance and high headroom of + 30 dBu. The OSC switch enables the console internal oscillator bus. The TALK switch makes possible to add talkback to the output of the subgroup by the Talk to Group function that is part of the playback/talkback module. The Mono Matrix adds both the stereo channel and makes it possible to use the complete subgroup channel in mono. The MNO switch inserts this matrix. The output of the bus amp drives the electronically balanced insert output section. The insert output is always available on the connector panel while the insert input is switched into the signal chain by the INS button. Insert input and output can handle level of + 30 dB. The insert point is pre the group fader.

The Group Fader is a conductive plastic stereo fader with 100 mm stroke and a maximum gain of 10 dB. It is combined with a CUT switch that mutes the entire group channel. The two mute groups of the small format broadcast console system BC1 can be also used with the subgroups. As usual, two switches are installed to select either one or both cut groups. The Stereo Balance Control operates with a center attenuation of 0 dB. The fader output drives the input of the balance control that feeds the routing section as well as the group output amplifier in post fader mode.

The PFL function can be set to AFL MODE by an additional switch on the top plate alternatively. Depending on the selected mode, PFL or AFL, the operation can be altered by additional jumpers. With PFL, the default mode is that PFL operates in latched mode when the fader is closed. Opening the fader resets PFL but it is also possible with fader open to press and hold the PFL switch. Actually, the cut function is included in the fader position. With active cut, the position of the fader does not matter. As long as cut is active, all functions are identical to cut inactive and fader closed. With AFL, these functions are changed, or it would only be possible to use AFL in latched mode if the fader is down or muted. If the latch mode is disabled in PFL mode with open fader or not is determined by a jumper. The selection of AFL and PFL does not change the main status functions PFL Add or PFL single. The entire PFL system operates in stereo.

The Group Output Amplifier defaults to the output of the fader section. An additional rotary level control can be inserted by the FDR ON switch. This pot controls only the output of the stereo group and does not change the signal that feeds the routing section. The PRE switch reroutes the input of the group output driver from post fader to pre fader. The outputs are electronically balanced; transformer balanced output are possible.

The Routing Section makes possible to feed the program master bus and all 12 sub groups as stereo pairs. This allows routing a subgroup into another subgroup. With extensive BC1 consoles, a complex and effective system or stacked, 'deep' groups can be configured. The risk of feedback by routing a group back to its own input is eliminated by jumpers on the module's PCB that can disable the routing into the own group bus.

The Stereo PPM Meters are installed in the module. In addition, an output for external meters is available. The integration of additional meters is possible with frame versions with meter bridge. The full range of ADT's PPM LED bargraph high resolution meters can be used as well as plasma bar graph meters, brand RTW. The internal meter has 20 LED's per channel and a display range from + 21 dB to - 36 dB. The release time is 1.5 seconds per 20 dB; the attack time is 1 ms. The level is internally adjustable to make possible to set up the system for the required nominal level. The meter reads the group output signal post the additional output fader. The METER TO FDR switch changes the meter to post fader, post balance control.

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

Stereo Subgroup Module SG