Crown VCAMC-8 Owners manual

VCA-MC Series Operation Manual

VCA-MC4A

VCA-MC8

1-VCAP

Obtaining Other Language Versions:

use of this product, please contact your local Crown Distributor. If you need assistance locating your local distributor, please contact Crown at 574-294-8000.

This manual does not include all of the details of design, production, or variations of the equipment. Nor does it cover every possible situation which may arise during installation, operation or maintenance.

The information provided in this manual was deemed accurate as of the publication date. However, updates to this information may have occurred. To obtain the latest version of this manual, please visit the Crown website at www.crownaudio.com.

Trademark Notice:

International. Other trademarks are the property of their respective owners.

Some models may be exported under the name Amcron.

Crown, Crown Audio and Amcron are registered trademarks of Crown

To obtain information in another language about the

4-VCAP

135504-5 5/08

VCA-MC Series Amplifier Accessories

The information furnished in this manual does not include all of the details of design, production, or variations of the equipment. Nor does it cover every possible situation which may arise during installation, operation or maintenance. If you need special assistance beyond the scope of this manual, please contact Crown Technical Support.

Crown Technical Support

1718 W. Mishawaka Rd., Elkhart, Indiana 46517 U.S.A.

Phone: 800-342-6939 (North America, Puerto Rico and Virgin Islands) or 574-294-8200

Fax: 574-294-8301 Internet: http://www.crownaudio.com

WATCH FOR THIS SYMBOL. The exclamation point triangle is used to alert the user to important oprating or maintenance instructions.

WARNING

TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE!

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FCC COMPLIANCE NOTICE

This device complies with part 15 of the FCC rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

CAUTION: Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

Operation Manual

VCA-MC Series Amplifier Accessories

Table of Contents

Important Safety Instructions .........................................................2

1 Welcome ...................................................... 5

1.1 VCA Module Features ........................................................6

1.2 1-VCAP Level Control Features .........................................6

1.3 4-VCAP Level Control Features .........................................6

2 How to Use This Manual .................................... 6

.......................................................... 7

3 Setup

3.1 Wiring to the 1-VCAP or 4-VCAP Wall-Mount Control ......7

3.2 Wiring Your Own Potentiometer ..........................................8

3.3 Wiring to an External Variable DC Voltage Source ............. 8

3.4 Bridge-Mono Wiring ..........................................................9

4 Operation ..................................................... 10

4.1 Operation Using the VCAP Wall-Mount Level Control ........ 10

4.1.1 Troubleshooting .........................................................11

4.2 Operation UsingYour Own Potentiometer or an

External 10 VDC Variable Source ........................................12

4.2.1 Troubleshooting .........................................................12

5 Theory of Operation ......................................... 13

6 Specifications ................................................ 14

7 Service . ...................................................... 15

7.1 International and Canada Service ........................................15

7.2 US Service ..........................................................................15

7.2.1 Service at a US Service Center ...................................15

7.2.2 Factory Service ...........................................................15

7.2.3 Factory Service Shipping Instructions ........................16

7.2.4 Packing Instructions....................................................16

7.2.5 Estimate Approval........................................................17

7.2.6 Payment of Non-Warranty Repairs...............................17

8 Warranty ...................................................... 18

Crown Factory Service Information Form ......................................21

Operation Manual

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VCA-MC Series Amplifier Accessories

Illustrations

Figure 1.1 VCA-MC4A Module .....................................................5

Figure 1.2 VCA-MC8 Module .......................................................5

Figure 1.3 1-VCAP Wall-Mount Level Control ..............................5

Figure 1.4 4-VCAP Wall-Mount Level Control...............................5

Figure 3.1 Wiring the VCA Level Control to the VCA-MC module. 7

Figure 3.2 Wiring Your Own Potentiometer ...................................8

Figure 3.3 Example Showing VCA1 and VCA2 Tied Together ........ 9

Figure 5.1 System Block Diagram ................................................13

Tables

Table 1. Attenuation per Detent of Crown VCAP Level Control........11

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Operation Manual

VCA-MC Series Amplifier Accessories

1 Welcome

The VCA-MC (VCA multichannel module) is an optional accessory module for the CTs 4200 or CTs 8200 power amplifier. The module provides independent remote level control for each channel. VCA-MC4A (Figure 1.1) is the VCA module for the CTs 4200. VCA- MC8 (Figure 1.2) is the VCA module for the CTs 8200.

VCA-MC4A Module

Figure 1.1

Figure 1.2

VCA-MC8 Module

Four-pin removable Phoenix-style barrier connectors provide the +10 VDC control voltage, ground, and control inputs for two amplifier channels. Thus, the 4-channel CTs 4200 uses two connectors; the 8-channel CTs 8200 uses four connectors. The control inputs are labeled VCA1 (for channel 1), VCA2 (for channel 2), and so on.

VCA-MC modules can be controlled in one of two ways:

• Optional Crown 1-VCAP or 4-VCAP wall-mount level controls

• An external control voltage of 0 to 10 VDC

1-VCAP: See Figure 1.3. Used in conjunction with a VCA-MC module, this is a singlegang panel with one potentiometer that provides remote volume control for one or more CTs amplifier channels. The potentiometer on the panel is wired directly to the VCA con-

nectors on the VCA-MC. 4-VCAP: See Figure 1.4. This is a two-gang panel with four potentiometers that provide remote volume control for four or more CTs amplifier channels. The potentiometers on the panel are wired directly to the VCA connectors on the VCA-MC.

1-VCAP Wall-Mount

Level Control

Operation Manual

Figure 1.3

Figure 1.4

4-VCAP Wall-Mount

Level Control

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VCA-MC Series Amplifier Accessories

1.1 VCA Module Features

• Provides independent remote level control for each channel of a Crown CTs 4200 or CTs 8200 power amplifier.

• Four-pin removable Phoenix-style barrier connectors provide the +10 VDC control voltage, ground, and control inputs for two amplifier channels.

• Can be controlled by Crown VCAP wall-mount level controls or external DC source (0 to 10 VDC).

• Any number of control inputs can be electronically tied together to control several channels from one VCAP or 10VDC voltage source.

• 0 dB attenuation default. If nothing is connected to a control input, the VCA module defaults to unity gain.

• VCA gain element is in series with amplifier attenuator, allowing the maximum gain of the system to be set at the amplifier.

1.2 1-VCAP Level Control Features

• Provides remote volume control for one or more CTs amplifier channels.

1.3 4-VCAP Level Control Features

• Provides remote volume control for four or more CTs amplifier channels.

2 How to Use This Manual

This manual provides you with the necessary information to safely and correctly set up and operate your amplifier accessory. It does not cover every aspect of installation, setup or operation that might occur under every condition. For additional information, please consult Crown’s Amplifier Application Guide (available online at www.crownaudio.com), Crown Tech Support, your system installer or retailer.

page 6

We strongly recommend you read all instructions, warnings and cautions contained in this manual. Also, for your protection, please send in your warranty registration card today, or register online at www.crownaudio.com. And save your bill of sale—it’s your official proof of purchase.

Operation Manual

VCA-MC Series Amplifier Accessories

3 Setup

It is important that you read and understand Section 4 “Operation” and Sec-

tion 5 “Theory of Operation” before completing the setup of the system. Seri-

ous damage may result to the loudspeakers if VCA operation is not well

understood.

The VCA-MC4A and VCA-MC8 can be controlled either by Crown VCAP wall-mount level

controls, by your own potentiometer, or by an external variable-voltage source (0-10 VDC).

3.1 Wiring to the 1-VCAP or 4-VCAP Wall-Mount Control

1. Install a single-gang junction box for the 1-VCAP or a double-gang junction box for the 4-VCAP. Run a cable between the junction box and the power amplifier, allowing some slack on both ends. No cable is provided. CAT-5 cable will work fine, but Crown recommends using standard twisted-pair shielded microphone cable.

2. See Figure 3.1. In this example, the twisted-pair HOT led is white; the twisted-pair COLD lead is black. On the VCAP circuit board, pull out and turn over the removable barrierstrip plug to expose the screws. Then connect the cable leads to the barrier-strip plug from left to right as follows: COLD lead, HOT lead, Shield. The facing side of the VCAP circuit board is labeled accordingly.

3. Turn over the barrier-strip plug and insert it into the socket in the VCAP level control.

4. Trap the cable under a wire tie inserted into the holes in the board as shown. Wire-tie holes are also provided on 4-VCAP panels.

Operation Manual

Figure 3.1 Wiring the VCAP Level Control to the VCA-MC Module

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VCA-MC Series Amplifier Accessories

5. Align a supplied barrier plug with the corresponding pins in the VCA-MC4A or VCA-MC8 module. Attach the cable to the plug as follows:

Connect twisted-pair HOT lead to the VCA channel terminal(s) you want to control. Connect twisted-pair COLD lead to the +10V terminal. Connect cable shield to the GND terminal.

The pin labeled GND on the VCA module is connected directly to the internal ground of the amplifier. NOTE: Do not connect this pin to any ground or extend it for any other

purpose.

In the VCAP wall-mount panel, do not connect the ground pin to the VCAP metal panel or its junction box.

3.2 Wiring Your Own Potentiometer

You may use your own linear-taper potentiometer to control the VCA-MC module. We recommend using a 5 k ohm potentiometer; however, values up to 100 k ohms are acceptable. A potentiometer near 100 k ohms may require an RFI bypass capacitor.

Wire the potentiometer as shown in Figure 3.2. Connect one end-terminal of the pot to the power-supply ground and VCA ground; connect the other end-terminal to +10 VDC, and connect the wiper to the VCA control input of your choice (VCA1, VCA2, and so on).

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Figure 3.2 Wiring Your Own Potentiometer

3.3 Wiring to an External Variable DC Voltage Source

The VCA-MC control input is the pin labeled VCA1, VCA2, and so on. It is possible to drive the control input from an external voltage source such as a Crestron control system. Connect a variable voltage source (0-10 VDC) between the ground pin and control input on the MC-VCA module. No build-out resistance is required. DO NOT connect to the +10V pin.

The voltage range of the control input is 0 TO 10 VDC. If this range is exceeded, proper operation is not guaranteed and damage may result to the VCA card or amplifier.

It is not recommended to draw more than 20mA from the 10V supply. (20mA is approximately equivalent to having a 5 k ohm potentiometer connected to each channel of an 8channel amplifier. Crown-supplied VCAP panels are equipped with 5 k ohm potentiometers). The 10V supply will survive a direct short.

Operation Manual

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