PDF User Manual

  1. Home
  2. Manuals
  3. Cloud CX-A4 Installation & User Manual

Cloud CX-A4 Installation & User Manual

Made by: Cloud
Type: Installation & User Guide
Category: Amplifier
Pages: 11
Size: 0.2 MB

 

Download PDF User Manual



Full Text Searchable PDF User Manual



background image

 
 
 
 

 

CX-A4 Amplifier 

Installation & User Guide 

V10.0

 

Cloud Electronics Limited 

140 Staniforth Road, Sheffield, S9 3HF England 

Tel + 44 (0) 114 244 7051 

Fax + 44 (0) 114 242 5462 

E-mail 

info@cloud.co.uk

Web site http://www.cloud.co.uk

 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

15-01-09 V10.0 

 
 

CX-A4 Amplifier 

Installation and operation manual 

 

Contents

 

 
 
 

Section

  

Page

 

 1 

Safety 

Notes...............................................................................2 

 2 

General 

Description ...................................................................2 

 

3 Installation ..................................................................................2 

 4 

Input 

Facilities ............................................................................2 

 5 

Output 

Details ............................................................................4 

 6 

100V 

Line 

operation ...................................................................4 

 

Configuring the CX-A4 for 100V Line operation .........................5 

 8 

Bridged 

Mode 

Operation ............................................................5 

 9 

Status 

Indicators.........................................................................5 

 10 

VCA 

Modules .............................................................................6 

 11 

Remote 

Level 

Plate Connections ...............................................6 

 12 

Bose

®

 Equalisation Modules ......................................................7 

 13 

Installing 

Optional Modules ........................................................7

 

 14 

Field 

Servicing............................................................................8 

 15 

General 

Specifications ...............................................................9 

 16 

Technical 

Specifications .............................................................9 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

1 Safety 

Notes 

 

Do not expose the unit to water or moisture 

 

Do not expose the unit to naked flames. 

 

Do not block or restrict any air vent 

 

Do not operate the unit in ambient temperatures above 35

o

 

Do not touch any part or terminal carrying the hazardous live symbol (    ) ) 

 

while power is supplied to the unit. 

 

Do not perform any internal adjustments unless you are qualified to do so and 
fully understand the hazards associated with mains operated equipment. 

 

The unit has no user serviceable parts.  Refer any servicing to qualified service 
personnel. 

 

If the moulded plug is cut off the lead for any reason, the discarded plug is a 
potential hazard and should be disposed of in a responsible manner.

 

For more detailed information refer to the rear of the manual. 

 

2 General 

Description 

The CX-A4 is a four-channel power amplifier with a maximum channel output of 120 watts 
into 4 ohms. The unit features extremely low distortion and low noise together with a high 
slew rate. Full circuit protection is provided and the load is disconnected if the heat sink 
overheats or any DC is detected at the output. A five-second switch-on delay operates to 
avoid any switching thumps or other extraneous signals reaching the speaker system. 
All four input amplifiers are balanced and connect via 3 pin XLR type connectors with 
adjacent level controls, all mounted on the rear panel. Input signal routing switches are 
provided and allow the unit to operate in many configurations whilst retaining simple input 
connections. 
The CX-A4 amplifier can be used with up to two optional plug-in two channel VCA 
modules to provide remote level control. Each plug-in module can operate as two 
individual attenuators or can be linked to operate as a stereo pair with one remote level 
control. 

 

3 Installation 

The CX-A4 is suitable for mounting in a standard 19" equipment rack and occupies two 
units of rack space. Sufficient ventilation must be provided for the unit. The amplifier 
draws cool air through the front panel and exhausts through the right side and care must 
be taken not to obstruct the airflow otherwise the unit may intermittently turn off due to the 
built-in thermal protection. Applications, which require long, sustained operation at high 
power levels, should allow a 1U space above and below the unit. The unit is 325mm deep 
but a depth of 400mm should be allowed to clear the connectors. 

 

4 Input 

Facilities 

All four inputs are balanced and use 3 pin XLR type connectors. All inputs are wired to the 
standard convention of pin 1 ground, pin 2 in-phase, pin 3 reverse phase, with the shell of 
the connector connected to the chassis. If the unit is operating in a location which has a 
high level of electrical or magnetic disturbance or is close to a TV or radio transmitter, we 
suggest that the input cable screen be connected to the shell of a metal XLR type 
connector. If the signal is from an unbalanced source, connect pin 3 to pin 1 (ground) 
inside the XLR type connector and use pin 2 as hot. 
Every input has a level control adjacent to the respective XLR type connector.  Input 
switching is provided on input channels 2 to 5 allowing a wide variety of input routing 
configurations. See the schematic diagrams showing details of various routing 
possibilities. 
With all input switches depressed, the unit operates as four independent amplifiers. 
Three stereo pairs, driven from one stereo source and four channels driven from one 
mono source are also possible together with a combination of the two by suitably 
configuring the input routing switches. 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

 
 
 
 

1

2

1

3

2

4

INPUT 1

1

2

3

4

POWER

AMPLIFIER

LEVEL

CONTROL

SOURCE

SWITCHES

INPUT

AMPLFIER

FROM MONO SOURCE

FOUR CHANNELS DRIVEN FROM ONE MONO SOURCE

1

2

3

4

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

1

2

1

3

2

4

INPUT 1

1

2

3

4

POWER

AMPLIFIER

LEVEL

CONTROL

SOURCE

SWITCHES

INPUT

AMPLFIER

FROM STEREO SOURCE

TWO STEREO PAIRS FROM ONE STEREO SOURCE

INPUT 2

1

2

3

4

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

 

1

2

1

3

2

4

INPUT 1

1

2

3

4

POWER

AMPLIFIER

LEVEL

CONTROL

SOURCE

SWITCHES

INPUT

AMPLFIER

INPUT 2

INPUT 3

INPUT 4

FOUR CHANNELS OPERATING AS INDEPENDENT AMPLIFIERS

1

2

3

4

 
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5 Output 

Details 

 
Four 2-pole plug-in screw terminal type connectors (5mm pitch) are provided on the rear 
panel for the four speaker outputs; these can accommodate flexible leads up to 2.50mm².  
The plugs for these connectors are provided in the accessory pack. If you require 
replacement plugs the Cloud part number is TP955188. 
Do not make any connections to the unit with the power cable attached.  
It is good practice to distance the output wiring from the input wiring and keep the 
speaker wires twisted until they are terminated to reduce any cross-talk to a minimum 
level. 

 

100V Line operation 

 

Connecting a CXL-100T 100W 100V-line module across an output of the CX-A4 will 
obtain a 100W 100V-line output from that channel.  The CXL-100T has to be mounted 
externally of the amplifier. A 2U 19" rack panel (CXL-800) is available that accommodates 
up to eight CXL-100T transformer modules. 
 

Using at least 1.5 mm² cable, wire the output of the amplifier to the 2 pole connector and 
connect to the CXL-100T ‘AMPLIFIER’ terminations observing polarity. The 70V/100V-line 
output uses the 3 pole connector; for 70V speakers, use the 0V (-) and 70V (+) 
terminations and for 100V speakers use the 0V (-) and 100V (+) terminations. The 
speaker cable must be at least 0.75mm², double insulated. With long distances it may 
advantageous to use thicker cable. The CXL-100Tprovides a fully balanced output signal 
which is isolated from the amplifier. 
 
The following page contains important information on configuring the CX-A4’s 65Hz filters 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

Configuring the CX-A4 for 100V-line Operation 

  

When a CXL-100 is connected to a channel of the CX-A4, that channel must have its 
65Hz high-pass filter operational.  Without this filter operational, the presence of high 
input levels at frequencies below 50Hz may result in transformer saturation causing the 
amplifiers VI limiter to operate.  The filter can be switched on by moving the relevant 
jumper to the ‘IN‘ position. 
Jumpers J1-4 are associated with the channels of the CX-A4 as follows: 

 

J1

 = Zone 1 

J2

 = Zone 2 

J3

 = Zone 3 

J4

 = Zone 4 

 

Diagram to Show Location of J1-4 on the CX-A4 PCB 

 

Bridged Mode Operation 

 
The unit can operate in Bridged Mode using any two channels.  The inputs must be wired 
together by linking the input signal at the XLR connectors of the two relevant channels, 
wiring the "second" input out of phase (i.e. pin 1 ground, pin 3 in-phase, pin 2 reverse 
phase).  The input level controls of the two channels should both to be set to the fully 
clockwise position. 
 
The output load should then be connected between the terminals marked “CHx” (where 
“x” represents the channel number) of the output connectors of the relevant channels. 
There is no connection to the terminals marked “0V” of the relevant channels.  
You must ensure that the positive wire is connected to the terminal marked “CHx” of the 
“first” channel used. The negative wire is connected to the terminal marked “CHx” of the 
“second” channel used, i.e. the channel with its input connected out of phase. 
 
Thus for example it is possible to configure four channels as two bridged outputs allowing 
a stereo input to be delivered to two 240 watt 8 ohm outputs. 
 

9 Status 

Indicators 

 
The front panel of the CX-A4 has an array of LED’s that indicate the status of all four 
channels. The lower green LED illuminates when a signal exceeding 500mW is detected, 
the yellow 'peak' LED will illuminate when the amplifier output is close to clipping and the 
top red LED indicates that the protection relay has disconnected the load. Please note 
that it is normal for all four red LED's to illuminate for approximately five seconds when 
the unit is switched on, indicating operation of the switch-on delay circuitry. The lower 
green LED indicates that the power is switched on. 
 
 
 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

 
 

10 VCA 

Modules 

 

A two-channel VCA module is available as a plug-in option for the CX-A4 (see section 13 
for installation details) and is supplied with either one or two control plates. The unit can 
operate two channels independently or switched to provide stereo attenuation via one 
control plate. For independent operation, the switch should be in the 'solo' position (in), 
with the remote level controls connected to both 3 pin connectors.  For stereo operation, 
position the switch in the link position (out) and connect the level control to the left 
connector only.  The RL-1 remote control plate is compatible with domestic electrical 
accessories and can be mounted onto a standard British flush or surface mounted 25mm 
deep back box. Two-core cable with overall screen should be used to connect the remote 
level control to the module mounted inside the CX-A4. The circuitry uses the industry 
standard 'Thats 2150A' VCA providing very low distortion and up to 90dB attenuation. The 
VCA module can be wired to provide muting by using an auxiliary relay connected to a 
fire alarm control panel. 

 

Note:

 A VCA module cannot be installed to channels that already have a stereo EQ 

adapter for Bose

®

 

equalisation modules installed. 

 

11 

Remote Level Plate Connections 

 
 
 

REAR VIEW OF CX-A4 AMPLIFIER

1 2

3

USE 2 CORE SCREENED CABLE

CONNECT SCREEN TO TERMINAL 1

REAR VIEW OF LEVEL CONTROL PLATE

LINK

REMOTE LEVEL

CLIP

PROTECT

OFF

ON

SOLO

1

2

1+2

1

2

SOURCE

1

2

3

1

2

3

1

2

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

 

12 Bose

®

 Equalisation Modules 

 
Each channel on the CX-A4 can have Bose

®

 

equalisation so that its output will be 

compensated correctly for a wide range of Bose

®

 speakers.  

 

Available Equalisation Modules:  

Bose

® 

Speaker models: M8, M16, M32, MA12, 402, 502A, 502B, 502BEX, 

802, MB4, MB24, LT3202, LT4402, LT9402, LT9702 

 

Bose

®

 equalisation modules must be fitted to a stereo 

EQ card adapter, Cloud part CA340166.The adapter is 
a stereo fitting, so will cover two adjacent channels of 
the amplifier. An equalisation module is required for 
each channel that is to be equalised, and it is possible 
to equalise a single channel using this module. 

 
Note:

  

 An EQ card adapter module cannot be installed to a 

pair of channels with a VCA module installed. 

 

13 

Installing Optional Modules 

 
There are three optional modules for the CX-A4; the VCA-2, the CA340166 Stereo EQ 
card adapter for Bose

®

 equalisation modules, and Bose

®

 equalisation modules.  

Components supplied with the various modules are listed below:- 

 

VCA-2:

 Two 40mm M3 hex spacers, one plastic insert & two 3-pin screw terminal plugs. 

CA340166 Stereo EQ card adapter:

 Two 25mm M3 hex spacers. 

Bose

®

 equalisation modules:

 No additional components. 

 

The CX-A4 connectors to install the VCA modules are to the rear of the amplifier on the 
input PCB clearly marked on the PCB as ‘CON X TO VCA MODULE’ where ‘X’ is 1 or 2 
see below: - 

 

 CON 

1

 = Channel 1&2 

CON 2

 = Channel 3&4

 

 

 Follow the instructions below carefully when installing modules. Incorrect installation can 
cause damage. 

 

1.  Turn the power off and remove mains cable. 
2.  Remove the top panel.  
3.  Select the CX-A4 connector you wish to install the module to (see notes above) and 

remove the jumpers from it. 

4.  When installing a VCA-2, remove the relevant rear panel blanking plate. 
5.  When installing a VCA-2, push the plastic plug into the rear panel ‘clip protect’ hole.  
6.  Two M3 fixing screws can be found adjacent to the CX-A4 connector.  Remove and 

retain these two screws then fix the M3 hex spacers in their place. 

7.  Push the 10-way plug onto the CX-A4 connector with the plug aligned so the cable 

approaches it from the rear of the chassis and check that the connector mates with all 
10 pins (important orientation diagrams can be seen on the following page).  

8.  When installing a VCA-2,

 

position the 3-pin sockets and switch of the VCA through the 

cut-outs in the rear panel. 

9.  Align the two holes in the module over the top of the two spacers. 

10.  Secure the module with the two M3x6 screws (removed earlier). 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

11.  When installing a Bose

®

 equalisation module to a stereo EQ adapter, remove the 

adapter jumper link for the channel to be equalised and fit the Bose® EQ module to the 
appropriate connector 

12.  When installing a Bose

®

 equalisation module, configure the relevant 65Hz filter to ‘IN’ 

and connect a CXL-100T 100V line transformer (see section 6) 

13.  Fit the top panel. 

 

EQ Adapter Module Orientation (Side View)           VCA Module Orientation (Side View) 

 

 

14 Field 

Servicing 

 

The CX-A4 is ruggedly built and uses proven reliable circuitry. It requires no more than 
the occasional removal of any dust that may have built up inside the unit as a result of the 
forced cooling. In the unlikely event of failure, the power amplifier module (2 channels) 
can be replaced without special tools and is available as a tested replacement complete 
with heat sink. Proceed as follows to replace the power module: 

 

Disconnect all the leads and connectors from the rear of the unit. 
Ensure that the mains supply lead has been disconnected. 
Remove the CX-A4 from the equipment rack. 
Remove the top panel. 
The power amplifier modules are arranged as two dual channel units. 
Locate the faulty unit and remove both the 7 way power cable & the 10 way ribbon 
connector. 
Remove the four fixing screws from the bottom of the unit to release the module. 
Now fit the replacement unit by proceeding in reverse order. 
No setting up is required and the unit should operate normally. 

 
 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

 

15 General 

Specifications 

 

Inputs 

Balanced via 3 pin XLR type connector. 

Outputs 

2 pin plug-in screw terminal type connectors for flexible cables up to 
2.5mm² 

Protection 

VI limiting, DC offset, Thermal and Switch-on Delay 

Status 

LED indicators on each channel for Signal, Peak & Protect. 

Cooling 

Force cooled using two speed DC fan. 

Dimensions 

482.6mm x 88.0mm (2U) x 325.0mm deep (+ connectors) 

Weight 9kg 

net 

 
16 Technical 

Specifications 

 

Rated Output 

120-watts/4 ohm load 85-watts/8 ohm load. 

Bridged Output 

240 watts/8 ohm load 

Frequency Response 

±1dB 10Hz to 50kHz 

THD 

<0.005% 1kHz  <0.05% 20Hz/20kHz 8

 1dB below rated output

VCA Module THD 

<0.03% 20Hz/20kHz 

Input Sensitivity 

0dBu (775mV) 

Input Impedance 

10k

 balanced / 5k

 unbalanced 

Noise   

>90dB below rated output. 

Slew Rate 

35V/

μ

S (power amplifier) 

Power Input   

230V ±5% (115V ±5% available) 

Fuse rating 

 

230V - T4A H   

115V - T8A H 

 

 
 

This product conforms to the following European EMC Standards

 
BS EN 55103-1:1997

 

BS EN 55103-2:1997

 

 

This product has been tested for use in commercial and light industrial environments.  If the equipment 
is used in controlled EMC environments, the urban outdoors, heavy industrial environments or close to 
railways, transmitters, overhead power lines etc. the performance of the unit may be degraded. 

 

The product conforms to the following European electrical safety standard. 

 
BS EN 60065:1998

 

 

 

Safety Considerations and Information 

 

The unit must be earthed. Ensure that the mains power supply provides an effective earth 

connection using a three wire termination. 

 

When the mains switch is in the off ‘O’ position the live and neutral conductors of the mains 

transformer are disconnected, however some parts of the product will still remain connected to 

the live and neutral mains conductors 

 

15-01-09 V10.0 

 


background image

CX-A4

 I

NSTALLATION AND OPERATION MANUAL

  

10 

 

 

CAUTION – Installation 

 

Do not expose the unit to water or moisture 

Do not expose the unit to naked flames. 

Do not block or restrict any air vent 

Do not operate the unit in ambient temperatures above 35

o

 

CAUTION – Hazardous Live 

15-01-09 V10.0 

 

Do not touch any part or terminal carrying the hazardous live symbol (    ) 

while power is supplied to the unit as it can result in electric shock. 

Terminals to which the hazardous live symbol refers require installation by qualified personnel 

 

CAUTION - Mains Fuse 

 

 

Replace the mains fuse only with the same type and rating as marked on the rear panel.  The 

fuse body size is 20mm x 5mm. 

 

CAUTION – Servicing 

 

 

The unit contains no user serviceable parts.  Refer servicing to qualified service personnel. Do 

not perform servicing unless you are qualified to do so. 

Disconnect the power cable from the unit before removing the top and do not make any internal 

adjustments with the unit switched on. 

Only reassemble the unit using bolts/screws identical to the original parts 

 

Bose

®

 is a Registered Trademark of The Bose Corporation 

 

In the interest of continuing improvements cloud electronics limited reserves the right to alter 

specifications without prior notice.  

 

Cloud Electronics Limited 140 Staniforth Road Sheffield S9 3HF England 

Telephone +44(0) 114 244 7051 Fax +44(0) 114 242 5462 E-mail: Info@cloud.co.uk