dbx Pro 166XL manual Limiter Section, Master Section, Rear Panel

dbx 166XL COMPRESSOR / GATE

BYPASS Button and LED:

Depress this button to Òhard-wire bypassÓ the 166XLÕs circuitry,(i.e., unaltered input signal will pass through the unit even if it is unplugged). Note that BYPASS works independently for each channel, even when the unit is stereo-coupled (via the STEREO COUPLE button).

In Bypass mode, the input is sent directly to the output, bypassing the 166XLÕs processing and controls and presenting unaltered input signal at the 166XLÕs OUTPUT. Bypass mode is especially useful for making comparisons between processed and unprocessed signals.

The BYPASS LED turns On in Bypass mode if the 166XL is being provided with AC power.

LIMITER Section

PEAKSTOP LEVEL Control and LED:

This control allows you to set the maximum peak output level of the 166XL regardless of any other control. PeakStop comes after the compression, gating and output gain circuitry; this provides for an absolute limit to be put on the peak excursions at the output. PeakStop works instantaneously; you can apply moderate amounts of dbxÕs OverEasy compres- sion and still be protected from large transients, other short-term overloads and overmodulation.

PeakStop is a smooth well-controlled soft clipper whose behavior is sonically similar to the gentleness of OverEasy compression; its clipping is much preferable to a power ampÕs or analog-to-digital converterÕs. PeakStop rounds the cor- ners of a peak rather than cutting it off sharply. By making a signalÕs leading and trailing edges curved instead of sharply angled, it reduces the amount of higher odd-order, offensive-sounding harmonics that conventional hard clipping causes. The level at which PEAKSTOP is activated is adjustable from +0dBu to +20dBu. Note that small signal excursions

above the set value of PEAKSTOP are possible, to allow the rounding to occur. Therefore, for applications where you must not exceed a given ceiling, set the PEAKSTOP control 1dB to 2dB below the ceiling.

The PEAKSTOP LED illuminates whenever peaks attempt to exceed PeakStop level and are reduced in amplitude. If the PeakStop LED illuminates when the PEAKSTOP LEVEL control is set to +20dBu, the headroom capabilities of the 166XL are being exceeded and hard clipping is occurring.

MASTER Section

STEREO COUPLE Button and LED:

This button toggles the unit between stereo and dual mono operation. Press the STEREO COUPLE button In for stereo operation where Channel 1 becomes the master controller for both channels. All of Channel 2Õs controls, buttons, and LEDs will be disabled (except for Channel 2Õs BYPASS, SIDECHAIN ENABLE, and CONTOUR buttons, and its GAIN REDUCTION LEDs), since Channel 2 is the Òslave.Ó Note that the detection circuitry senses the true RMS levels of the combined signal, so it is unaffected by phase shifts (or other discrepancies) between the channels. This ensures stereo compression without loss of imaging stability.

With the STEREO COUPLE button Out, the unit functions as two separate mono compressor/gates, each with its own independent controls.

The STEREO COUPLE LED indicates that the 166XL is stereo-coupled.

Rear Panel

15 WATTS			PHONE:	MANUFACTURED UNDER ONE OR MORE OF THE FOLLOWING U.S. PATENTS 4,234,804 4,316,107 4,329,598 4,331,931 4,377,792 4,403,199 4,409,500 4,425,551 4,434,380 4,454,433 4,471,324 4,473,793 OTHER PATENTS PENDING
					CHANNEL 2			CHANNEL 1
			TIP			SIDECHAIN			SIDECHAIN
			RING	OUTPUTS	INPUTS	INSERT	OUTPUTS	INPUTS	INSERT
						TIP=INPUT			TIP=INPUT
						RING=OUTPUT			RING=OUTPUT
			SLEEVE		+4 dBu			+4 dBu
		PROFESSIONAL PRODUCTS	XLR:		-10 dBV			-10 dBV
		A HARMAN INTERNATIONAL
		COMPANY	PIN 1
		SALT LAKE CITY, UTAH	PIN 2
100V	50/60Hz	MADE IN USA
120V	60Hz	MODEL 166XL	PIN 3
		COMPRESSOR/LIMITER/GATE

INPUT (BALANCED) Jacks:

The Tip/Ring/Sleeve phone jack and XLR-type jack are wired in parallel; either INPUT will accept an audio signal for processing by the 166XL. The phone jack accepts a standard TRS 1/4Ó phone plug for a balanced input source, or a 2-cir- cuit (Tip/Sleeve) 1/4Ó phone plug for an unbalanced source. The XLR-type jack is wired pin 2 HOT (+), pin 3 COLD (-) and pin 1 GROUND.

Note: Only one input jack should be used at a time, except for “splitter” applications where one input jack is used as an input and the other input jack is used as an output (see “Using the SIDECHAIN INSERT” section on page 16). Since a given pair of channel input jacks (e.g., Channel 1 XLR INPUT and Channel 1 1/4” INPUT) are internally connected (TIP = Pin 2, RING = Pin 3, SLEEVE = Pin 1), if one of the jacks is unbalanced, then the other jack will be unbalanced. For example, if a 1/4” INPUT jack is used with a mono cable, and is therefore unbalanced, the XLR INPUT jack will also be unbalanced (Pin 3 shorted to ground).

OPERATING LEVEL Switch:

This switch selects between a -10dBV and +4dBu nominal operating level. When the switch is in the in position, a

-10dBV operating level is selected. When it is in the out position +4dBu is selected. A -10dBV operating level should be