dbx Pro 160A manual Installation Considerations, Input/Output Cable Configurations

dbx 160A COMPRESSOR / LIMITER	®
	PROFESSIONAL PRODUCTS

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 stu- dio is not fully balanced, you must ground the unused XLR pin (either pin 2 or 3) or use the 1/4Ó 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 ÒSpeaker Protection, page 7)

INSTALLATION CONSIDERATIONS

Input/Output Cable Configurations

Hookups and Cabling

The 160A is a 600½, 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 >40k½ 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. (Òin phaseÓ)

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 phaseÓ).

Output Cable Considerations

The model 160A has two separate outputs: one single-ended amplifier driving the 1/4Ó stereo phone jack, and a separate active-balanced amplifier driving the XLR-type OUTPUT jack. Each is capable of driving a 600½ load to +24dBu.

160A

SIGNAL FLOW

Figure 7: Signal Flow (Balanced Connection)

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