API 525

Originally released in the 70's, the API 525 is a "feedback" type compressor. An input (threshold) control and output (make-up gain) control are provided, along with an additional "Ceiling" fine-tune function which can increase gain reduction (lower threshold) while simultaneously raising output level to match, so the user can alter dynamics "on the fly" without level changes. A compression/limit switch sets ratio at either 2:1 or 20:1. Attack time is as fast as 15u/s. Four auto release modes are offered via two switches, 0.1s, 0.5s, 1.5s, & 2.0s. A De-Ess function inserts an inverse vocal energy curve filter in the detector for effective sibilance/pop reduction. The 525 design has been taken from the original blue prints and spec control drawings from the API archives.

Release times vary with frequency, with high frequency / full bandwidth content released faster than lower frequencies for natural envelope tracking. Attack time is fixed, chosen to catch the fastest peaks, without "pumping". Equally useful as a tracking, mixdown or program compressor/limiter, the 525 utilizes "vintage" dynamics control and an easy to use multi-function control set. The 525 has a hard-wire bypass switch, a balanced input, and a pinout that is the same as all the other 500 series modules. Two or more 525s can be linked for multi-channel compression.

The API 525 Compressor makes use of the 2510 and 2520 op-amps and exhibits the reliability, long life, and uniformity which are characteristic of all API products.

• 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

INPUT IMPEDANCE:

> 30 K Ohms, Balanced

OUTPUT IMPEDANCE:

100 Ohms, Transformer coupled, Balanced

OPERATING LEVELS:

-15 dBu to +20 dBu

MAXIMUM GAIN REDUCTION:

25 dB

NOISE:

98 dB below +10 dBu output, at 10 dB of Compression

HARMONIC DISTORTION:

0.5% Max, 30 to 20 kHz

ATTACK TIME:

15 micro seconds

RELEASE TIMES:

.1, .5, 2.0, 2.5 seconds

DE-ESSING:

Inversion of the Voice Energy Curve

SLOPES:

Compression, 2:1, Limit, 20:1

METERING:

Compression or Limiting-Illuminated Analog dB meter, shows Gain Reduction

FREQUENCY RESPONSE:

±.5 dB, 30 to 20 kHz

POWER REQUIREMENTS:

±12/18 Volts/DC, @80 ma.

SIZE:

1.5" X 5.25" X 7.5" Deep

SIZE (BOXED FOR SHIPPING):

4.5" X 6.5" X 10"

ACTUAL WEIGHT:

1.77 lbs.

SHIPPING WEIGHT:

2.17 lbs