dbx 160A - Manual (Page 16)

dbx 160A COMPRESSOR / LIMITER
Note: DO NOT CONNECT the output of a power amp or the speaker out of an instrument to the input of the 160A. Severe damage to
system components may result.
Patch Bay
In the studio, the 160A may be connected to a patch bay to allow it to be used anywhere in the studio system. If your studio
is not fully balanced, you must ground the unused XLR pin (either pin 2 or 3) or use the 1/4” phone jack OUTPUT, which
is single-ended. Another option is to have a qualified technician install an optional output transformer, which will require
grounding of either pin 2 or 3 of the XLR-type OUTPUT.
Sound Reinforcement
To compress a live mix or to protect loudspeakers, connect the 160A between the source (mixing board or distribution
amp) and the power amp(s). If multi-way loudspeakers with low-level electronic crossovers are used, the 160A(s) should
go after the crossover(s). For a stereo system, you can separately stereo couple the two high band crossovers, low band
crossovers, etc. (see page 10). If limitations require that you use a single 160A before a crossover, adding an equalizer to
the side chain may provide some additional protection to your high frequency components (see
“Speaker Protection, page
7).
INSTALLATION CONSIDERATIONS
Input/Output Cable Configurations
Hookups and Cabling
The 160A is a 600 Ω, balanced (differential) unit designed for nominal +4dBu levels; inputs and outputs are tip/ring/sleeve
phone jacks and XLR-type jacks. The 160A can be used with either balanced or unbalanced sources and outputs can be
used with either balanced or unbalanced loads, provided you use proper cabling.
A balanced line is defined as two-conductor shielded cable with the two center conductors carrying the same signal but of
opposite polarity with respect to ground. An unbalanced line is generally a single-conductor shielded cable with the center
conductor carrying the signal and the shield at ground potential .
Input Cable Configurations
The 160A has an actual input impedance of >40k Ω in balanced or unbalanced configurations. This makes the 160A audio
input suitable for use with virtually any source impedance, low or high. The 160A's input jacks are wired in parallel. That
is, the phone jack TIP (+) connection is internally wired to the XLRe pin 2, the RING (-) is wired to pin 3, and the
SLEEVE (shield) is wired to pin 1. Note that pins 2 and 3 are the reverse of certain older dbx and other manufacturer's
equipment, but if the same connection is used at both the input and the output, the signal will be correctly polarized. (“in
phase”)
Reversing the input wires to the input terminals will result in the output signal polarity being the opposite of the input sig-
nal (180° out of phase”).
Output Cable Considerations
The model 160A has two separate outputs: one single-ended amplifier driving the 1/4” stereo phone jack, and a separate
active-balanced amplifier driving the XLR-type OUTPUT jack. Each is capable of driving a 600
Ω load to +24dBu.
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166A
SIGNAL FLOW
160A
Figure 7: Signal Flow (Balanced Connection)