Chameleon Labs 7721 Stereo VCA Compressor

When designing the Chameleon Labs 7721, Chameleon’s engineers started with a clean sheet of paper and deeply evaluated the details associated with developing a bus compressor for the modern studio. Basing detection and voltage control on a voltage control amplifier (VCA) topology and designing a circuit that provides low noise and transparency the team created an acoustic “glue" that is capable of consistently delivering punch and loudness to the signal.

The 7721 provides a classic set of adjustable settings as well as controls only available on esoteric compressors, including:

• Soft Knee / Hard Knee – Allows you to change between a softer arriving compression effect and a faster arriving, limiting type effect.
• Peak / RMS – This control allows you to choose between the Peak and RMS detection schemes that are quite different. Peak detection engages the compressor by monitoring peak or instantaneous voltage signals. RMS engages by looking at the average energy in the signal and comparing it to the threshold setting. Very different modes of operation that provide great solutions for specific problems.
• High Pass Filter – If you decide to use a Side Chain signal as the compression trigger signal, you can use the High Pass Filter to high the audio signal and avoid pumping effects.
• Classic Controls – Threshold / Attack / Release / Ratio – Low ratios provide a nice starting place for master transparency, 4:1 provides more color and higher ratios for a tougher sound full of character.
• Blend – This control allows you to blend, or mix, the original uncompressed signal with the compressed signal providing another tool you can use to obtain your desired objective.
• VU Meter - Monitor Input, Outputs and Gain Reduction levels.

Features:

• Stereo compressor with VCA-based signal detection
• Super low noise, IC based input section
• Side chain input allows a separate source to be used as the compression trigger
• IC based, ultra-low noise output stage
• VU meter for Input / Output Level and Gain Reduction monitoring
• Super low noise internal power supply
• Selectable high pass filter
• Threshold, Attack, Release and Ratio controls
• Selectable detection type Peak or RMS
• Selectable compression types: Soft or Hard Knee
• Blend control allows you to mix the compressed audio signal with the original signal