The API 527A Compressor/Limiter is a VCA-based compressor with variable gain reduction methods for switching between “feed-forward” and “feed-back” styles of compression. Users who are familiar with the 225L, 529, 2500, or 2500+ will easily recognize the NEW / OLD gain reduction switch on the front panel. The 527A features an improved LED gain reduction meter and a hard bypass switch for enhanced usability.
Engineers fell in love with the 527’s flexible signal gain control. API designed the 527A with the same control features for adjusting the compressor’s gain reduction behavior. For classic “feed-back” performance, switch to OLD. The NEW setting enables a “feed-forward” gain reduction style that relies on RMS detectors for the gain control voltage, which is typical for newer VCA-type compressors.
Compressed signals can be adjusted via continuously variable threshold, ratio, attack/release, and output level controls. Switchable SOFT / HARD knee settings further modify the compressor’s character to toggle between natural or sharp responses. API also included a patented THRUST® function that inserts a filter before the RMS detector circuit. The THRUST switch allows the compressor to preserve the articulate low-end.
Versatility is matched by efficiency. The consistent output level makes live adjustments possible without perceivable gain changes in the program level. Like the original 527, this version also makes use of 2510 and 2520 discrete op-amps and can be combined via DC link for multichannel applications.