Dbx 117 119 Owners Manual

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PRINTED IN USA

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Dear Audio Enthusiast,

The engineers who developed the DBX 117 are enthusiasts too. Now you have
purchased a DBX 117, and we wish you many hours of listening enjoyment

Our owners manual contains full details on how to operate your unit, plus an
explanation of how it works. After reading the manual we hope you will
experiment with the DBX 117 until it is a familiar tool for dynamic range
modification

Sincerely, DBX Inc.

The development of two scientifically optimum, electronic devices make the
DBX 117 the world's first successful dynamic range modifier. The first device is
a gain control element with very low noise and decilinearl response. Thesecond
is a true R.M.S.2 detector which responds to audio signals in much the same way
that the human ear responds to sounds. These two devices together overcome
the previous limitations and disadvantages of expanders or compressors. With the
DBX 117 you can expand or compress the dynamic range and reduce the
apparent background noise of any audio signal.

Dynamic range is the relationship or ratio between the softest and the loudest
sound in a musical passage. The ratio is conveniently expressed in decibels or
d83.

Music in live performance often has a dynamic range of 70 to 90 dB. This range
is somewhat greater than can be accomodated by records, tapes, and FM
broadcasting. A 40 to 50 dynamic range is all that these media normally achieve.
Recording engineers therefore compress the dynamic range of music until it fits
the recording medium. The result is that all the sounds are there, the softest and
the loudest, but no longer in their original relationship. The impact of the
original performance has been diminished and in many instances you are left
with a flat, dull recording.

The DBX 117 can reexpand the limited dynamics of tapes, records, and FM
broadcasts and bring your music back towards its original dynamics. The 117 is
easily connected to your receiver or integrated amplifier-preamplifier (see figure
1 or 2).

decilinear r (t.m. DBX Inc.) linear in dechels.

2 R.M.S. - root mean square: the sum of the powers of each separate frequency component
of the signal.

adecibel (dB) -1/10 of a Bel. The logarithm of the ratio between two signal levels, Hence
IOdB = 10:1 ratio of power; 20dEI = 100:1 ratio; SOdB = 100,000,000:1 ratio; etc.

SPECIFICATIONS

COMPRESSION & EXPANSION
Continuous from 1.4 compression slope (14 dB output change/20 dB input
change) to 2.0 expansion slope (20 dB output change/1O dB input change).

DYNAMIC RANGE
120 dB input or output

INPUT NOISE
-1 10 dBm typical, ~100 dBm maximum

INPUT LEVEL
Maximum input signal in excess of 30 Volts ARMS

INPUT IMPEDANCE
50K ohms

OUTPUT LEVEL
Maximum output 10 Volts RMS open circuit; +17 dBm into 600 ohms

OUTPUT IMPEDANCE
500 ohms

DISTORTION

0.5% maximum @20 Hz, 0.2% typical above 50 Hz for complete cycle of
compression and expansion, 1.2% @20 Hz for 2:1 expansion; 05% typical @
1KHz and above for any setting of controls.

,(3 Volts RMS or less input or output.)

FREQUENCY RESPONSE
+0, -1 dB 20 Hz - 20 KHz

ATTACK TIME

50 dB/m.Sec. maximum initial attack rate @1.4 expansion. 12 mSec. to 85% of
final value @ any setting of compression or expansion. Adjusted to be within
integrating time of human ear within the constraints of reasonable low
frequency distortion.

RELEASE (DECAY) TIME
Constant rate 140 dB/sec.(Norm) or 50 dB/sec.(Slow) @ 1.4 expansion,

LEVEL MATCH CONTROL
Unity gain point may be varied from 100 mV. to 1 Volt.

POWER CONSUMPTION
115 VAC. 50-60 Hz 2 Watts.

SIZE
3 /4 H, 5 %" W, 9" L.

WEIGHT
4.5 lbs.

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