QSC Audio DD1-3 manual Introduction, II. Installation, ON/OFF Control, Inputs, Output Monitors

Instructions for the DDI-3 DataPort Accessory Card

I. INTRODUCTION

The DDI-3 DataPort Accessory Card converts a QSC amplifier’s DataPort to an eight-position terminal block, providing convenient access to the pins of the amplifier’s DataPort; this is useful for connecting input signals or implementing a remote on/off (standby) system without using a DataPort cable. Four solder pads provide access to the amplifier’s output voltage and current monitors.

QSC ISA, CX, DCA, SRA, PowerLight, and PowerLight 2 Series amplifiers feature a DataPort for every two audio channels. Therefore, one- and two-channel models have one DataPort, while four-channel models have two and eight-channel models have four. On the four- and eight-channel CX and DCA models, only the DataPort for channels 1 and 2 has the power supply standby feature. ISA models do not have power supply standby or output voltage and current monitoring.

ON/OFF CONTROL	VMN1	STBY
		CGND
A TTL-type logic low at DataPort pin 2, such as a short to ground (Figure 2), puts the power supply in	IMN1	CH2+
		CH2-
standby. Opening the short will restart the power supply, with no inrush current surge. To control multiple
	IMN2	AGND
amplifiers with a single switch, use diodes to isolate them from each other (Figure 3).	VMN2	CH1+
		CH1-
		AGND

VMN1	STBY
	CGND
IMN1	CH2+
	CH2-
IMN2	AGND
VMN2	CH1+
	CH1-
	AGND

Figure 1. The DDI-3

Run

Standby

INPUTS

Through its DataPort, an amplifier’s input sensitivity (the input voltage required to reach full rated output power) is approximately 3 volts RMS, at full gain and with an 8Ω load on each channel. Use the + and -

Figure 2. On/off control of a single amplifier

terminals for balanced connections; the AGND terminal is audio ground, for conecting a cable shield when necessary. For unbalanced connections, connect the signal conductor to the + terminal and the cable shield to both the AGND and - terminals.

OUTPUT MONITORS

There is a VMON and an IMON output for each amplifier channel. The VMON output is a sample of the amplifier channel’s output voltage, scaled so that full output into an 8Ω load equals approximately 3 volts RMS. The IMON output is a voltage proportional to and in phase with the amplifier channel’s output current; the scaling varies among the various amplifier models; contact QSC for details if you wish to use this feature.

VMN1

IMN1

IMN2

VMN2

VMN1

IMN1

IMN2

VMN2

STBY CGND CH2+ CH2-

AGND CH1+ CH1-

AGND

STBY CGND CH2+ CH2-

AGND CH1+ CH1-

AGND

II. INSTALLATION

The DDI-3 kit (QSC part # SG-000235-00) includes these items:

DDI-3 board

Two #4-40 × ¼” black screws

Installation guide

		Run
		Standby
VMN1	STBY
	CGND
IMN1	CH2+
IMN2	CH2-	1N914, 1N4148, etc.
	AGND
VMN2	CH1+
	CH1-
	AGND

Figure 3. On/off control of several

Use this procedure to install the DDI-3: amplfiers with a single switch

1.Turn off the amplifier.

2.If you are using the output voltage or current monitoring features, solder the wires to the appropriate pads on the DDI-3 before attaching it to the amplifier.

3.Plug the DDI-3 into the amplifier’s DataPort. Use the two screws included to secure it; do not overtighten them.

4.To attach a wire to the DDI-3, strip about 5 mm (0.2”) of insulation from the wire. Twist the exposed wire strands together and make sure there are no stray ones. Turn the screw on the terminal counterclockwise until you can fully insert the wire end into the terminal. Turn the screw clockwise until the terminal clamps the wire securely. Repeat for all the wires needed.

5.The amplifier is ready for use.

2