527A Compressor/Limiter

The API 527A is a versatile and modern VCA-style compressor/limiter that packs an incredible amount of control and character into a single-slot 500 series module. Building on the legacy of API's dynamic processors, the 527A offers a different flavor compared to the feedback-style 525, providing the precise and punchy sound characteristic of feed-forward VCA compressors. This makes it exceptionally well-suited for a wide range of applications, from transparently controlling the dynamics of a mix bus to aggressively shaping drums, bass, and vocals. Its comprehensive feature set gives engineers the flexibility to dial in almost any compression characteristic imaginable, from smooth and subtle to hard and aggressive.

The 527A stands out with its extensive control set. It features continuously variable controls for Threshold, Ratio (from 1:1 to ∞:1), Attack, and Release, allowing for precise dynamic shaping. A key feature is the switchable "Thrust" circuit, a patented design that places a high-pass filter before the RMS detector, resulting in a punchier low-end by reducing the compressor's reaction to low-frequency energy. The user can also choose between "New" and "Old" modes, which select between feed-forward and feedback compression topologies, respectively, effectively giving you two distinct compressor types in one module. Additionally, the sidechain can be shaped using an internal filter, and the compression can be triggered by either Peak or RMS detection. A 10-segment LED meter provides clear visual feedback for gain reduction. This combination of features makes the 527A one of the most powerful and flexible compressors in the 500 series format.

Features

• VCA-based compressor/limiter for the 500 Series format.
• Continuously variable Threshold, Ratio, Attack, and Release controls.
• Switchable "New" (Feed-forward) and "Old" (Feedback) compression types.
• Patented "Thrust" circuit for punchier low-end.
• Selectable Peak or RMS detection.
• 10-segment LED meter for Gain Reduction and Output Level.
• Sidechain input and built-in sidechain high-pass filter.
• Linkable for stereo operation with another 527A.