Stereo bus compressor with expanded variable threshold, blend/mix function, and proprietary 2520 op-amps
The 19-inch, rack-mountable unit features a dual-channel design that can be configured for stereo compression or for use as two separate units via a single compression setting.
Among the many qualities which make the 2500+'s unique is its use of API's patented THRUST circuit for a chest-hitting, punchy bottom end. Another distinctive feature of the 2500+ is its selectable "old" or "new" compression, with the old style using the "feed back" type of compression found in the API 525, and the new style using the "feed forward" type in which the compressor side chain is fed directly from the unit input. Additionally, the output stage of the 2500+ offers an auto-makeup gain button that permits the user to vary the threshold or ratio while automatically maintaining a constant output level.
Added to the 2500+ is the Mix/Blend circuit. First featured in the limited production 50th Anniversary Edition, Mix/Blend control provides either cross fader or parallel mixing of the compressed and uncompressed signal. Three different user settings are offered:
OFF - compressed signal only
X (Cross) - allows the MIX control to adjust between 100% uncompressed to 100% compressed - increasing one, while decreasing the other
|| (Parallel) - allows the MIX control to dial in compressed signal to blend into the uncompressed signal, (which remains the same).
The 2500+ ensures fidelity with its fully balanced design and two front panel VU meters showing input, output and gain reduction levels.
API 2520 Op Amps
Expanded variable threshold between -20dBu to +20dBu
Selectable ratio, attack, and release times
Patented THRUST filter with 3 settings for frequency dependent side chain control
Variable link between left and right channels
Old "feed back" and new "feed forward" compression
Soft, Medium, or Hard knee for easy to sharp compression
Auto or manual gain make up
1/4" balanced side chain inputs
Output clips at +32dBu
New Mix/Blend circuit
"Over Threshold" LED illuminates when input audio crosses the set threshold
Stereo analog meters to show input level, output level, and gain reduction
Full hard-wired relay bypass