Classic Gear: dbx 160

Written by Joe Cenedella (New England Institute of Art AKA A.I. New England)

dbx 160 (1976) Designed by David Blackmer, using early Overeasy circuit and RMS detection

The dbx 160 was introduced in 1976 as a professional quality compressor/limiter.  The brainchild of David E. Blackmer (founder of dbx) it quickly became a must have for studio engineers of the time.  Besides being one of the earliest compressors, the dbx 160 introduced to the market features that allowed for a much smoother and more natural sounding compression.  The 160 uses voltage controlled amplifiers (VCAs) which adjust gain settings to fluctuate with the voltage creating smooth and natural sounding compression that closely simulates how the human ear interprets sound. Along with the VCA the dbx 160 introduced true RMS detection paired with feed forward gain reduction. This allows the model to achieve an infinite compression ratio (120:1) without excessive gain levels, and without excessive distortion, which causes oscillation in the feedback loop. All models of compressors at the time the dbx 160 was introduced gave the user some control over compression in the form of preset ratios (10:1, 20:1). (source) this is where the VCA’s come in allowing the attack and release to fluctuate with the input signals envelope. This allowed for more of a set it and forget it approach instead of constantly adjusting the ratio throughout a performance.

The Features:

Auto detected/attenuated 40dB for ground loop hum

Introduced “over-easy” compression, or soft knee compression

Adjustable threshold 10mV-3V

LEDs for input level, output level, or gain

First to have fully adjustable compression up to 120:1

RMS detection, VCAs, and Feed Forward gain reduction

VU origin adjustable 20dB (+/- 10dB input)

Mono inputs, two required for stereo tracking

Output level of +/- 26dB Hi-Z, +/-24dB Lo-Z

Cost New: $300 in 1976

Cost Now: pair sells on ebay for $1600

Link to user manual: http://mixonline.com/online_extras/dbx_160.pdf

Official dbx Pro Audio Info: http://www.dbxpro.com/vintage_download.php?product=160

Other Sources:

http://mixonline.com/TECnology-Hall-of-Fame/1976_dbx_160VU_complimiter/index.html

http://www.barryrudolph.com/mix/comp.html

http://en.wikipedia.org/wiki/Variable-gain_amplifier

http://en.wikipedia.org/wiki/Dbx,_Inc.

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