Feedforward Stereo Compressor with Make-Up Gain
„Stereo Compressor“ is a classic analog feedforward compressor, which takes its sidechain split directly from the input signal. It is based on the THAT4305 Analog Engine® single-chip with integrated Blackmer® VCA. It has two independent signal paths in order to process stereo signals. The left input is normalized to the right, if you want to compress mono signals instead. The module has three controls and a switch:
THRESHOLD determins the level at which the compressor starts working. This can be set from -40dB to 20dB.
RATIO sets how much the compressor turns down the volume when the threshold is reached (INF:1 to 1:1).
GAIN regulates the amount of make-up gain (-20dB to +20dB) that is applied to the signal.
Additionally there is an ON/OFF switch that makes it easy to compare the dry and compressed audio signal.
Please note that if you turn THRESHOLD counter-clock wise to the left, you reduce the threshold from 20dB (fully cw) to -40dB (fully ccw). Hence the compressor starts working earlier. If you turn RATIO counter-clock wise to the left you increase the amount of compression from 1:1 (fully cw, no compression) to INF:1 (fully ccw, infinite compression). So turning the knobs down corresponds to compressing the signal. The pictures below show the knobs in a neutral position where no compression is applied.
STEREO COMPRESSOR has a similar design as the STEREO SUM CHANNEL modules. If you want to add some compression to your mix STEREO COMPRESSOR is a perfect addition to your STEREO SUM Mixer.
• Analog Compressor
• Stereo Signal Path
• THRESHOLD, RATIO and GAIN
• ON/OFF Switch for Signal Comparison
• Up to +20dB Make-Up Gain
• STEREO SUM Compatible
• Skiff friendly
• Wrong polarity protection
The module consists of two boards:
• Front PCB Panel
• Main PCB
- 35 mA +12V
- 26 mA -12V
- 0 mA 5V
- 30 mm deep