Cloud CX-A450 User manual

Clearly better sound
Cloud Electronics Limited
140 Staniforth Road, Shefeld, S9 3HF. England. Telephone: [phone] Fax: [phone] Web: www.cloud.co.uk Email: [email protected]
The Cloud CX-A450 and CX-A850 are high-quality multi-
channel power ampliers designed for relatively low-power sound
reinforcement applications in commercial or industrial premises.
They are ideal for situations where the various locations of the
building require different programme material and/or levels.
The two models are:
MODEL POWER
CX-A450 4 x 50 W
CX-A850 8 x 50 W
The ampliers will deliver their rated power into 4 ohm loads for
long periods of time. Safety features of the design include Cloud’s
Dynamic Clipping Protection circuitry, VI limiting, switch-on delay
(5 seconds) and protection against DC offset or thermal overload.
Both models are built in a 2U steel enclosure, and use variable–
speed forced-air cooling.
Any two channels may be wired in Bridge Mode, allowing power
outputs of double the normal rating to be delivered to a load of
8 ohms (minimum).
In addition to the power switch and associated LED, the front panel is
tted with three LEDs for each channel, conrming signal presence,
peak level and activation of the protection circuitry. Rear panel
controls are provided for individual channel gain trims and input
routing to congure the amplier in various combinations of mono,
stereo or multi-channel operation. The inputs are electronically
balanced.
The CX-A450 and CX-A850 may also be used with 100 V/70 V-line
loudspeaker systems by the addition of standard Cloud accessories.
The CXL-4160 is a four channel transformer module which can
be internally tted to the CX-A450, while the CXL-40T is a single
channel toroidal transformer module for external mounting. For
installation convenience, the CXL-800, a 2U rackmounting assembly
which can hold up to eight CXL-40s, is also available. To prevent LF
transformer saturation in 100 V/70 V-line systems, a 65 Hz high-pass
lter may be enabled for each channel individually, by internal jumper.
Other standard options are Cloud RL-1 remote volume control
plates, the VCA-5 single-channel VCA card (required for level
control by RL-1), and EQ cards to suit various makes and models of
loudspeakers. Remote level control or speaker EQ may be tted to
any or all channels.
Cloud CX-A450 - front panel view
Cloud CX-A850 - front panel view
CX-A450
FOUR
CHANNEL
POWER AMPLIFIER
PROTECT
PEAK
SIGNAL
POWER
4 3
21
EIGHT CHANNEL POWER AMPLIFIER
CX-A
850
1
2
3
4
5
6
7
8
PROTECT
PEAK
SIGNAL
POWER
CH 1
REMOTE
LEVEL
123
RL-1
123
CH 2
REMOTE
LEVEL
RL-1
2
13
3
2
1
CH 3
REMOTE
LEVEL
RL-1
2
13
3
2
1
CH 4
REMOTE
LEVEL
RL-1
2
13
3
2
1
1
3
21
LEVEL
2
3
21
LEVEL
3
3
2
1
LEVEL
4
3
21
LEVEL
POWER INPUT
FUSE
REPLACE FUSE
WITH SAME TYPE
AND RATING
230V - 3.15A H
115V - 6.3A H THIS PRODUCT MUST BE EARTHED
40-60Hz
5%
V
SPEAKER OUTPUTS
MINIMUM LOAD 4OHMS
OUTPUT RATING 50W/4OHMS
100V/70V LINE
OUTPUTS
CH1
CH2
CH3
CH4
1
2
12
3 4
(OUT)
(IN)
(IN)
(OUT)
(IN)
(OUT)
CH1
0V 0V
CH2
0V
CH3
0V
CH4
SOURCESOURCESOURCE
HIGH VOLTAGE
THIS COVER
REMOVE
DO NOT
OUTPUT
DANGER
LINE
100V/70V
REMOTE
LEVEL
REMOTE
LEVEL
REMOTE
LEVEL
REMOTE
LEVEL
REMOTE
LEVEL
REMOTE
LEVEL
REMOTE
LEVEL
REMOTE
LEVEL
FUSE
230V - T4A
115V - T8A
CH 1
RL-1
1
23
1
2 3
1
23
RL-1
2 3
1
1
23
RL-1
2 3
1
1
23
RL-1
2 3
1
1
23
RL-1
2 3
1
1
23
RL-1
2 3
1
1
23
RL-1
2 3
1
1
23
RL-1
2 3
1
CH CH CH CH CH CH CH
2345 6 78
1
2
1
2 3
LEVEL
SOURCE
-
-
-
2
(OUT)
(IN)
(OUT)
1
(IN)
3
3
SOURCE
LEVEL
1
2 3
-
-
-
(OUT)
2
(IN)
4
4
SOURCE
LEVEL
1
2 3
-
-
-
(OUT)
1
(IN)
5
5
SOURCE
LEVEL
1
2 3
-
-
-
(OUT)
2
(IN)
6
6
SOURCE
LEVEL
1
2 3
-
-
-
(OUT)
1
(IN)
7
7
SOURCE
LEVEL
1
2 3
-
-
-
(OUT)
2
(IN)
8
8
SOURCE
LEVEL
1
2 3
-
-
-
LEVEL
1
2 3
-
-
-
1
SPEAKER OUTPUTS
OUTPUT RATING 50W / 4OHMS
MIN LOAD 4 OHMS
0V
CH1
0V
CH2
0V
CH3
0V
CH4
0V
CH5
0V
CH6
0V
CH7
0V
CH8
POWER INPUT
REPLACE FUSE WITH SAME
TYPE AND RATING
THIS UNIT MUST BE EARTHED
5%
40-60Hz
CLOUD MULTI-CHANNEL POWER AMPLIFIERS
MODELS CX-A450 & CX-A850
Cloud CX-A450 - rear panel view
Cloud CX-A850 - rear panel view
General Description

Clearly better sound
CX-A850 ONLY
Block Diagram
• General purpose, high quality 4 and 8-channel power ampliers
with superior audio performance
• 4 x 50 W (CX-A450) or 8 x 50 W (CX-A850) into 4 ohms
• Very low inter-channel crosstalk
• Thermal protection
• VI limiting
• DC offset protection
• Dynamic Clipping Protection
• Switch-on delay (for speaker protection during power rail
stabilisation)
• Pairs of channels may be operated in Bridge Mode
• Per-channel, front-panel LEDs for signal presence, peak level
and protection status
• Balanced line level inputs with gain trim
• Rear panel switches to congure for multichannel, stereo or
mono operation
• Optional internal 4-channel 100 V/70 V transformer module
(CX-A450 only)
• Optional externally-mountable 100 V/70 V transformers (per-
channel)
• Optional remote volume control (per-channel)
• A range of optional per-channel EQ cards, to match various
popular loudspeakers
• 2U 19” rackmounting units
• Variable speed forced-air cooling
• Five year warranty

Clearly better sound
Input Routing
The input routing switches of the CX-A450 and CX-A850 permit
various permutations of mono, stereo and multi-channel operation
without any external parallel wiring. Some possibilities are shown
below:



























 







































 













Clearly better sound
































































In another situation, it might be necessary to route the same
audio to several different zones, but allow each zone to adjust
its own level. This can be easily achieved by providing each zone
with a Cloud RL-1 remote volume control plate, and setting the
amplier’s input routing to parallel all the channels. Only a single
input feed needs to be supplied, to Channel 1
System Example
CX-A450 and CX-A850 ampliers’ exceptional crosstalk
performance make them particularly suitable for any application
where different audio sources need to be routed to various zones
(parts of a building). They are equally suitable in a situation where a
common audio source needs to be reproduced at different levels in
various zones. The exibility of the ampliers’ input routing makes
it possible to handle a mixture of mono and stereo sources without
complex wiring.
In many applications, the power ampliers will be used in combination
with a Cloud Zoner, to permit paging and emergency override. An
example is the CX263 zoner, which supports three zones, one of
which may be stereo. In the example shown below, where a CX263
is used with a CX-A450, Chs. 1 & 2 are used to drive stereo to Zone
1, while Chs. 3 & 4 are used for the mono signals to Zones 2 and 3
respectively.
Similar mono-stereo arrangements are possible with the Cloud
CX163 and Z4II zoners.

Clearly better sound
Graphs
A
udio Precision05/31/11 15:06:04CXA450 Frequency Response
ColorSweep TraceLine Style ThickDataAxis Comment
1 1 Blue Solid 2 Anlr.Level ALeftCH2 Freq Response Sig=-6dBu
-3
+3
-2
-1
+0
+1
+2
d
B
r
20 20k50 100200 500 1k 2k 5k 10k
Hz
A
udio Precision05/31/11 11:22:06CX-A850 Frequency Response
ColorSweep TraceLine Style ThickDataAxis Comment
1 1 Red Solid 1 Anlr.AmplLeftCH2 Frequency response
-3
+3
-2.5
-2
-1.5
-1
-0.5
+0
+0.5
+1
+1.5
+2
+2.5
d
B
r
20 20k50 100200 5001k 2k 5k 10k
Hz
A
udio Precision05/31/11 12:21:05CX-A450 Crosstalk
ColorSweep TraceLine Style ThickDataAxis Comment
1 1 Red Solid 1 Anlr.BandpassLeftCH2 to CH1
-100
+0
-80
-60
-40
-20
d
B
r
20 20k50 100200 500 1k 2k 5k 10k
Hz
TT
A
udio Precision05/31/11 13:23:50CX-A850 Crosstalk
ColorSweepTraceLine Styl e ThickDataAxis Comment
1 1 Red Solid 1 Anlr.BandpassLeft
-100
+0
-80
-60
-40
-20
d
B
r
20 20k50 100200 500 1k 2k 5k 10k
Hz
T
A
udio Precision05/31/11 13:11:
59
CX-A450 THD+N
ColorSweep TraceLine Style ThickDataAxis Comment
1 1 Red Solid 1 Anlr.THD+N Ratio Left
0.05
0.3
0.1
0.15
0.2
0.25
%
20 20k50 100200 500 1k 2k 5k 10k
Hz
T
A
udio Precision05/31/11 13:27:
47
CX-A850 THD+N
ColorSweep TraceLine Style ThickDataAxis Comment
1 1 Red Solid 1 Anlr.THD+N Ratio LeftCH2 THD+N Sig=-10dBu
0.05
0.3
0.1
0.15
0.2
0.25
%
20 20k50 100200 500 1k 2k 5k 10k
Hz
T

Clearly better sound
Technical Specications
CX-A450 CX-A850
Performance Output Power (Normal Mode): 50 W/ch into 4 ohms (all chs driven) 50 W/ch into 4 ohms (nominal, continuous sinewave)
Output Power (Bridge Mode): 100 W nominal into 8 ohms
Frequency Response: 10 Hz – 20 kHz, +0/-0.5 dB
High Pass Filter: -3 dB @ 65 Hz, switchable per-channel
Distortion:
THD+N: <0.02% typical, 1 kHz,
60 W into 4 ohms, one channel driven,
22 Hz – 22 kHz
THD+N: <0.007% typical, 1 kHz,
60 W into 4 ohms, one channel driven,
22 Hz – 22 kHz
Noise: <-96 dB rel. rated output, unweighted, 22 Hz – 22 kHz
Crosstalk: <-70 dB, rel. rated output into 4 ohms,
10 kHz
<-82 dB, rel. rated output into 4 ohms,
10 kHz
VCA module THD+N: <0.03%, 1 kHz, 22 Hz – 80 kHz BW
Inputs Type & connectors Electronically balanced, 3-pin 3.5 mm-pitch screw-terminal connectors
Sensitivity 0 dBu (0.775 Vrms)
Input Impedance 10 kohms (balanced)
General Output Connectors (lo-Z) 2-pin 5 mm-pitch screw-terminal connectors
Output Connectors (100/70 V) Screw terminals
Power input 230 V ±5% (115 V ±5% available)
Mains protection Replaceable fuse, T3.15A H Replaceable fuse, T4A H
Amplier Protection VI limiting, DC offset, Thermal, Switch-on Delay & Dynamic Clipping Protection
Status Indicators Signal present, Peak & Protection
Cooling Force cooled, variable speed DC fan
Dimensions (W x H x D) 482.6 x 88 (2U) x 300 mm
Weight 7.15 kg 8.8 kg

Clearly better sound
E&OEIssue_1.0
The power ampliers shall be available in four channel and eight channel
versions. Either version shall be capable of driving 50 W per channel
into a 4 ohm load when all channels are driven simultaneously.
The ampliers’ front panels shall incorporate an AC power switch,
an LED indicating POWER ON, and LEDs indicating Signal Present,
Peak Level and Protect status for each channel. The Signal Present
LEDs shall illuminate when the output level is 22 dB below the rated
output. The Peak LEDs shall illuminate at the onset of signal clipping.
The Protect LEDs shall indicate activation of the channel protection
circuitry.
The ampliers shall be provided with one input per channel and
be able to operate in the following congurations as a minimum:
all channels independent, one input feeding all channels or two
inputs feeding the amplier channels in pairs for stereo operation.
Signal level adjustment will be provided for each channel via a rear
panel control permitting a range of operation from not less than
90 dB attenuation (min.) to unity gain (max.). The inputs shall be
electronically balanced and capable of operating with both balanced
and unbalanced sources. The input impedance shall be 10 kohms
(balanced). The input connectors shall be of Euroblock type. It shall
be possible to enable a high-pass 3rd-order lter with a turnover
frequency of 65 Hz independently in each amplier channel.
Each channel shall deliver its rated power from an input signal
of 0 dBu with input level controls set at maximum. Output mute
protection on power-up and thermal protection shall be provided.
The ampliers will also be protected against short-circuits at the
output, and excessive combination of output voltage and current. The
ampliers’ outputs shall be on Euroblock connectors.
A range of optional, single-channel transformer modules, and suitable
rackmounting housings, shall be available to permit the ampliers
to drive 100 V-line and 70 V-line loudspeaker systems. It shall also
be possible to adapt the four channel amplier version for direct
connection to 100 V-line and 70 V-line systems by the addition of an
internally-tted four-channel transformer module.
An optional remote control shall be available for any or all amplier
channels, to allow adjustment of channel gain. The remote control
connector shall be of Euroblock type. It shall also be possible to t
optional EQ cards to any or all channels to suit a range of current,
popular loudspeaker types.
The amplier shall be built in a steel chassis suitable for mounting in
a standard 19” equipment rack, and occupy two rack spaces. Variable
speed forced-air cooling shall be employed.
The amplier shall be available in versions operating on either 230 V
or 115 V AC mains, the intended mains voltage to be specied by the
user at the time of order.
The power ampliers shall be the Cloud CX-A450 (four channels)
and CX-A850 (eight channels).
Architect’s and Engineer’s Specication