The API 525 discrete compressor / limiter module is a classic '70s design reissued for the wildly popular 500 Series format. This feedback-type design is versatile enough for use with all kinds of sound sources, from drums to vocals to the final mix, controlling dynamics and putting an awesome sonic stamp onto your tracks. The unique "Ceiling" control lets you compress while maintaining level, allowing for true A/B comparisons, and the all-discrete circuitry means you've got API's signature punch and lightning-fast response in this workhorse module.