Blue 230
Dual Mono / Stereo Compressor & Limiters
The controls of both of these Dual / Stereo Compressor and Limiter modules are identical for each
of the two channels and are simple to use, and are described from left to right along the front panel:
Mains switch - this is an illuminated push switch, the indicator is an LED cluster, lit when On.
In switch - an illuminated push switch, the indicator is an LED and lit when the compressor stages
are in circuit.
Key switch - an illuminated push switch, the indicator is an Led and lit when the side chain is being
fed from the key input and not the main signal input.
Make-up Gain control - a variable control which allows gain to be applied to the signal via the VCA
element.
Ratio control - providing a switched range of ratios for the compressor action .
Threshold control - switched .
Attack control - a continuously variable attack speed from Fast to Slow.
Release control - another continuously variable control for release timing. This control may be
overridden by selecting the Auto Release function using the illuminated push switch, where-upon
the release timing is programme level dependant.
The controls mentioned above, Ratio, Threshold, Attack and Release all affect the compressor
function only, having no effect upon the limiter function which has its own controls to the right
hand side of the module.
Next are two PPM meters one for each channel which normally display input signal level.
The meter sensitivity can be switched between two sensitivities. Normally the meter will read 0VU
for an input signal level of +4dB.
With the +10dB switch selected the meter will read 0VU for +14dB signal level input, this is 10dB
higher than standard so that input signal peaks may be read clearly.
There is a single switch marked Gain Change, when the LED is illuminated the meters display the
gain changes of the Compressors. With no Compressor gain change the meter will read 0VU. Any
gain change will be displayed directly in dB, thus 6dB of compressor action will result in a meter
reading of -6dB. Please note that the meters do not display the action of the Limiter, there is a
separate LED for the Limiter action.
The Stereo switch - an illuminated push switch which changes the module from a dual to a true