Chameleon Labs 7721 Stereo VCA Compressor is a stereo bus compressor built around a VCA detection circuit, with full control over threshold, ratio, attack, release, and makeup gain, along with modern additions like blend control, sidechain filtering, and selectable peak or RMS detection.

This is a flexible compressor designed to sit across a mix bus, subgroup, or stereo source and control dynamics without flattening the signal. The VCA topology gives it a fast, controlled response, while the available detection modes let you shift between catching transients and responding more to overall program material.

Peak and RMS detection modes change how the compressor reacts to incoming signal. Peak mode responds quickly to short, sharp events like drums and percussive sources, while RMS mode follows the average energy of the signal, making it more suitable for buses, bass, guitars, and full mixes.

The sidechain section includes a selectable high-pass filter that affects only the detector circuit, not the audio path. This allows low frequencies to pass through without triggering excessive compression, helping maintain weight in the low end while still controlling midrange and transient energy.

A dry/wet blend control allows parallel-style compression directly from the front panel, letting you retain transients while adding controlled density underneath. The soft/hard knee switch adjusts how aggressively compression is applied, from a more gradual onset to a firmer, limiter-like response.

The unit features stereo inputs and outputs, a fully balanced signal path, and a VU meter that can display input, output, or gain reduction. The internal universal power supply allows for clean integration into a permanent rack setup.

This is a practical tool for shaping dynamics on mix buses, drum buses, stereo keys, playback rigs, and other sources where control and cohesion matter more than heavy-handed effect.

• Stereo VCA compressor with balanced inputs and outputs
• Threshold, ratio, attack, release, and makeup gain controls
• Selectable Peak or RMS detection modes
• Sidechain input with selectable high-pass filter (detector circuit only)
• Dry/Wet blend control for parallel compression
• Soft/Hard knee switch for compression character
• VU meter with input, output, and gain reduction monitoring
• Fully balanced output stage
• Internal universal power supply