George Massenburg Labs - GML 8900 - Dynamic Range Compressor

Twenty-two years of progressive research into loudness perception resulted in a limiter/compressor unlike any other. The 8900 Dynamic Range Controller was intrinsically developed to react to loudness (rather than volts) like our ears do.

The 8900’s psycho-acoustic approach uses multiple true-RMS detectors, remarkably accurate log converters, and fast peak detectors to respond intelligently to real signal energy, not just level. This unusual design employs unique controls, like Crest Factor, Timing, and Release Hysteresis to access the parameters that you really want to adjust. Familiar features such as Stereo Link, Soft/Hard Knee, Ratio, Output Level, as well as the comprehensive 40- segment tricolor Gain/Loss metering have been carefully optimized for flexible, creative control over a wide dynamic range with a lack of audible artifacts. Very useful is the Side Chain Input that permits external frequency shaping to be introduced into the detection circuitry. The entire audio path is all-discrete, including the VCA, for unsurpassed transparency and low-level resolution. The 8900 packs all of this in a formidable 2U, two-channel unit which requires requires the external GML 9015 Power Supply.


Technical Specifications :

INPUT

20 kOhm balanced bridging; Pin 3 hot
57 dB common mode rejection at 20kHz
+27.4 dBv maximum before clipping
Individually channel switchable on back panel for +4 or -10

THROUGHPUT

±0.1 dB, 16 Hz to 68 kHz response (controls at zero)
0.01% Harmonic distortion at any frequency 20 Hz - 20 kHz 1 , no gain reduction
0.009% SMPTE Intermodulation distortion 2
30 v/usec discrete low noise, high performance amplifiers
no electrolytic interstage or output coupling capacitors
noise -96.5 dBv bypassed, -74 dB absolute worst case (control position dependent)
rolloff: 3 dB down at 260 kHz
FORM FACTOR - 2 CHANNELS, Each with Separate Peak and Dual RMS Detectors
Discrete VCA; Discrete Audio Chain
Front Panel Sidechain; Stereo and multiple unit control link
40 Segment Tricolor meter; Meter range -20 to +20, true gain through unit
4 segment instantaneous ratio meter (approximate indication of soft knee actuation)
Peak, FastRMS and SlowRMS indicators

OUTPUT
+27.4 dBv clipping; unbalanced; Pin 3 Hot
3 mv output offset, stabilized by D.C. servo correction

OTHER
external power supply: ±28 VDC & ±18 VDC
ground and chassis straps at rear
19" x 3 1/2" rack case, black anodized aluminum, silver legend, 8 1/2" deep
weight: 7 lbs.

Requires the external GML 9015 Power Supply sold separately