The Rolls CL151 GLC is a unique dynamics processor with the added benefit of a microphone preamp. The unit features smooth, soft-knee compression and limiting, and noise gating for quiet operation. Gating is indicated by a front panel LED, and gain reduction is indicated via a 5-LED ladder.
The plug connected to the Tip is the "Send" which will connect to the Input of the signal processing device, and the Ring is the "Return" which connects directly to the detector (compression control) circuit.
Side Chain circuits are often used in "ducking". Ducking is momentarily lowering one signal under another signal. For example, you may wish to automatically lower a music signal under a paging microphone signal, then have the music return to normal level after the page is over. This would be accomplished by running the music into the compressor, and having the page signal connect into the Side Chain return. The page signal must also be connected to the main mixer or amplifi er as well. When the paging signal begins, its signal goes to the main mixer and the Side Chain circuitry. The music is compressed or "ducked" under the page.
To access the compressor detector circuit directly, Rolls has included a Side Chain jack. The Side Chain works somewhat like an effects loop, with a send and return point. A 1/4" Tip-Ring-Sleeve "Insert Cable" is required to utilize the Side Chain.