VC2 6
A COMPRESSOR is a device which reduces the dynamic range of
programme material.
WHAT IS A COMPRESSOR?
A perfect compressor is an amplifier where the input/output ratio is constant: So using a
2:1 compressor, increasing the input by 2dB gives a corresponding 1dB increase in the
output. Early compressors which used variable mu thermionic tubes or photoelectric
devices only approximated true compression over a limited range. They had a soft
'threshold' where compression started and held to a predictable ratio up to a certain
level, then they returned to a more linear amplification allowing transients through. This
is in stark contrast to modern VCA compressor/limiters where designers latched onto
the idea that a compressor should be entirely linear in its compression characteristic
(regardless of the sound produced) and thought it 'sensible' to combine the functions of
compressor and limiter to 'stonewall' any and all signals above a certain level.
The musical effect is that VCA compressors sound muddy and flat, while the historic
compressors sound lively and retain sparkle.
But all compressors change the sound to some extent. The JOEMEEK Tube Channel
compressor adds 'punch' and 'bite' without the dull muddiness of all others.
USING THE COMPRESSOR.
A compressor IN/OUT switch is fitted. When this switch is pressed the LED indicator
alongside switches off in preparation for a red "compression" signal.
To USE the compressor, set the COMPRESSION control to somewhere near full up.
Set ATTACK to minimum (full anticlock) and RELEASE to halfway. Switch the VU meter
to "COMP. METER" (switch out).
If there is sufficient audio signal from the input amplifiers, the meter will start to indicate
compression by the needle moving downwards. The compressor should now be
working and ears can take over the adjustments.
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