Channel in a Box (click for larger image)

As one might expect, the CIB offers both Line and Mic paths. However, as well as separate inputs, the Mic and Line sections also have separate output connections, and both paths can pass audio at the same time. The EQ section includes high- and low-frequency filters, two switchable-bandwidth LF and HF EQs and a 2-band, midrange parametric equalizer. Filter, EQ and dynamics sections are normally in the mic signal path, but the CIB has the unique ability to route all three sections to the mic, the line or the sidechain signal path of the compressor.

Logical Layout The front panel shows, from left to right, the order in which the audio signal flows through the CIB’s processing sections. There is no way to re-order the way the processing sections are connected together, such as putting the compressor after the filter but before the equalizer. The intended design allows you to insert only the required processing sections; unneeded sections may be bypassed, thus keeping the audio path pristine as possible. Some alternate routing options would enhance the unit’s versatility.

Each section features the same trio of Alps button switches: an In/Section Bypass switch; a Line switch that flips the section from the normal Mic path to the Line path; and a Sidechain button that routes the section’s function to the sidechain input of the compressor. Switching to sidechain lifts that section from either Mic or Line paths. The sidechain feature allows you to set up any combination of shelving EQ, parametric or high/lowpass filtering, but the lack of an additional rear panel insert jack means you cannot add external processors to the sidechain.

The CIB is powered by an internal switching power supply made by Harman International and fitted with a newly updated, small and quiet cooling fan. The CIB makes use of two different analog chips: the Motorola MC33078 and the high-slew-rate Burr-Brown OPA2134, both dual-op amp packages.

Microphone Preamp Section
Starting at the left side of the CIB are the microphone and line input sections. The mic input circuit is called a T.L.A., or Transformer-Like Amplifier, because it behaves electrically just like a transformer by using a common mode rejection input coil. Input impedance is 5k ohms, and there is a rotary stepped gain setting control graduated in 6dB steps from 0 dB up to a whopping +72 dB. An additional mic gain trim control provides ±6dB fine adjustment. The manual states that the mic input can accept up to +20dBu levels without using an attenuator pad (the unit has none), so the mic input could easily double as a second line input. Additional switches in this section include those for phase flip and phantom power, and there is a small LED meter to indicate input levels in either Mic or Line paths. One quirk: You can monitor the output levels of both the Line and Mic paths, but you will have to find the Source button at the other end of the front panel in the Output section. The Source button reads the level before the output trim fader and indicates the level through the unit or, if you are using the compressor, the final makeup gain level.

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Reprinted with permission from Magazine, November, 2000
© 2000, Intertec Publishing, A Primedia Company All Rights Reserved