The API 525 is a fully discrete feedback type compressor (a la 1176, 660, etc.) in 500 series format, the orginal 525 was first manufactured 30 years ago - it offers compression or limiting

Unique ceiling control linking threshold and make-up gain on one pot, there is also a de-ess switch. The 525 goes beautifully before the 550B EQ for killer kicks and snares, or after the 512C mic pre for rich vocals.

The main features of the API 525 include:

• Exact reissue of API's original 525 from the early 70's
• Peak detecting "feedback" compressor/limiter
• Variable Threshold and Output levels
• Unique "Ceiling" control combines key functions
• Analog VU meter for monitoring gain reduction
• 4 Switchable release modes
• De-Ess function
• Traditional API fully discrete circuit design
• Active Balanced Input/Output
• Hardwire bypass