API 527 Compressor/Limiter Module
Features
• Audio circuit uses the 2510 and 2520 Discrete Op Amps with transformer output
• Continuously variable detented Threshold control
• Continuously variable detented Attack and Release controls
• Continuously variable detented Ratio control
• Output Fader level control
• 10 segment VU/Gain Reduction meter with selector switch
• Overload LED
• “Link” switch for multiple unit interdependent compression linking
• “New”/”Old” switch for feed-forward or feed-back compression
• “Hard”/”Soft” compression curve knee switch
• Patented THRUST® switch for frequency dependent side chain control
• “IN” switch with hard relay bypass when in the “Out” position
The API 527 takes it’s place alongside the family of API VCA based compressors, the 225L and the 2500 Stereo Bus Compressor. Anyone familiar with those units will immediately be at home with the 527. Features common to the line like “feed forward” (NEW) and “feed back” (OLD) gain reduction methods selectable on the front panel, provide a choice of “that old way”, or “the new way” of compression, for the highest level of flexibility in signal gain control. The “old way” or Feed-Back method is what most of the classic compressors used for the gain control circuit. The “new way” gain reduction is more typical of the newer VCA type compressors that rely on RMS detectors for the gain control voltage.