API Audio 225L 200 series Compressor / Limiter


Discrete Channel Compressor

Manufacturer Description:


  • Threshold control from -20 to +10 dBu
  • Variable compression ratio from 0 to infinity
  • Adjustable release time from 50m/sec to 3 sec
  • "OLD" or "NEW" sound
  • HARD or SOFT compression knee
  • Always at unity gain, regardless of settings
  • LED Gain Reduction meter
  • API 2510 and API 2520 op-amps
  • Transformer output to +28 dBu

The API 225L Compressor is ideal for all studio, live sound and broadcast applications. Regardless of the threshold or ratio settings, the output level always remains at unity. This unique feature allows for real-time adjustments without the need for changing the output level.

Both NEW ("feed forward") and OLD ("feed back") methods are selectable on the front panel, providing two choices of gain reduction. NEW gain reduction is typical of the newer VCA type compressors that rely on RMS detectors for the gain control voltage. OLD or Feed-Back method is what most of the classic compressors used for the gain control circuit. There also is a SOFT or HARD selector. SOFT provides a more subtle compression resulting in a very natural, less compressed sound. HARD results in a more typical, sharp knee type compression that has a much more severe limiting effect.

Release time is adjusted by rotating the REL knob. Release time constants: 50m/sec to 3/sec. Attack time is switch selectable to Fast (2mS), Medium (18mS) or Slow (75mS).

The 225L is designed for individual channel use or, through the use of the external LINK function, two units can be combined for Stereo applications via a rear access pin. The 225L also has a side-chain input for the detector amplifier.

The 225L can be used in the Legacy, Legacy Plus or Vision Series Consoles, or in the L200 Rack. The 225L Compressor makes use of the 2520 and 2510 op-amps and therefore exhibits the reliability, long life and uniformity which are characteristic of all API products.

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Sound Pure
Durham, NC
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