Gain Structure - Intelix 4001 VC User Manual

Intelix VC Series Mic/Line Mixer User Manual

4.0 Gain Structure

To obtain the best performance from your Intelix VC Series mic/line mixer, you should first
understand the basic gain structure of the unit. There are four stages of gain adjustment
(labelled #1 through #4 in the drawing below):
1) channel input gain/trim control: this rear panel potentiometer controls the gain of the
microphone preamplifier.
2) channel volume knob: this front panel potentiometer controls (through the channel VCA)
the amount of channel that is fed to the mixer's summing bus.
3) master volume control: this front panel potentiometer controls (through the master VCA)
the amplification of the summing bus to the output connector.
4) external amplifier volume control (not part of the mixer): sets the final listening level of
the loudspeakers.
The goal of setting up the mixer's gain structure is to adjust these four controls for the desired
volume, while maintaining the best possible signal-to-noise ratio (S/N) through the mixer. This
is done by setting controls 2 and 3 at "7" where S/N and headroom are optimized, using
controls 1 and 4 to achieve maximum gain before distortion.
In order to maintain the highest level of S/N in the mixer, the audio signals are never brought
through the front panel controls of the Intelix mixer. Instead, each front panel pot controls a
Voltage Controlled Attenuator (VCA), which controls the associated amplification stage. The
channel VCAs do not control an amplifier, but are attenuation only devices which determine
the amount of each channel's contribution to the summing bus.
Note: The VC and VCX models differ slightly in their setup procedures. Use the procedure
appropriate to your model (Section 4.2 for VC; Section 4.3 for VCX).
intelix
13