CX2300
Active Filter
Installation & User Guide
Cloud Electronics Limited
140 Staniforth Road, Sheffield, S9 3HF England
Tel +44 (0)114 244 7051
Fax +44 (0)114 242 5462
e-mail
web site http://www.cloud.co.uk
info@cloud.co.uk
CX2300 I
NSTALLATION AND OPERATION MANUAL
CX2300 Active Filter
Installation and operation manual
Contents
Section Page
1 Introduction ................................................................................................1
2 Active Filters and Crossovers.....................................................................2
2.01 Why use an Active Filter/Crossover ? ........................................2
2.02 What are the optimum crossover frequencies?..........................3
2.03 Why 3 pole filters ?..................................................................... 3
1
3 Installation..................................................................................................4
3.01 Installation notes for the experienced installation engineer........ 4
3.02 Mounting ....................................................................................4
3.03 Audio Connections.....................................................................4
3.04 Schematic Diagram....................................................................5
3.05 Power connections..................................................................... 5
3.06 Plug-in Filter Cards ....................................................................5
4 Operation and Controls ..............................................................................6
4.01 Two Way Operation ...................................................................6
4.02 Do I use the 20Hz high pass filter ? ...........................................6
4.03 The Invert Switch .......................................................................6
4.04 The Mute Switch ........................................................................6
4.05 The Gain Controls...................................................................... 7
5 Circuit Description ...................................................................................... 7
5.01 Schematic diagram ....................................................................7
5.02 The Audio Path ..........................................................................7
5.03 The Power Supply...................................................................... 8
5.04 Signal Connections and EMC ....................................................8
5.05 The benefits of balanced interconnections.................................8
5.06 Using the CX2300 with unbalanced equipment..........................8
5.07 40Hz - the minimum frequency. .................................................8
6 How to change the frequency of the filter card. ..........................................9
6.01 Table of resistor values for the filter card ...................................9
7 Technical Specification.............................................................................11
1 Introduction
The Cloud CX2300 3 Way Stereo Active Crossover has been designed without
compromise to operate with very low levels of noise and distortion as part of a high
quality professional sound system. A high degree of security is provided by using fixed
frequency plug-in filter cards together with a tamper proof cover for the front panel. Once
the unit has been correctly installed, no unauthorised adjustments can be made thus
maintaining system integrity and reliability.
Balanced audio connections are used throughout via Neutrik 3 pin XLR type connectors
with gold plated pins. We suggest that balanced interface connections are used wherever
possible, even for very short interconnections to take advantage of the common mode
rejection and freedom from earth loops when wired correctly.
The control layout is very simple and logical with each frequency band having its own
stereo controls for gain, phase invert and mute. In addition, a 20Hz high pass filter can be
switched in or out of the signal path. All these controls and switches, including the power
switch are protected by the security cover supplied with every unit.
Plug-in fixed frequency filter cards determine the frequency characteristics of the CX2300
and these can be specified from the list detailed in section 6.01. To change the frequency
of any filter card, refer to the component list in section 6.01 which gives details of
resistors which should be fitted to the filter card to achieve a particular frequency.
Experienced installers who are fully conversant with the Active filters and
Crossovers skip to section 3 for installation details.
2 Active Filters and Crossovers
2.01 Why use an Active Filter/Crossover ?
Virtually all high quality speaker systems whether domestic or professional use two or
three drivers to cover the whole of the audio spectrum with each driver specially designed
to reproduce a finite frequency range. In most low to medium power speaker systems, a
single full range power amplifier would be used to feed a passive crossover to filter the
signals to the two or three speakers within the full range enclosure. There are several
disadvantages when using full range amplification and passive filters; any differences in
driver efficiency have to be corrected by adding power resistors which is both wasteful
and reduces driver damping; High order passive filters with good attenuation levels are
expensive and inefficient; Any distortion present in the power amplifier is heard across the
whole audio spectrum.
A well designed fully active system will overcome all of the above problems, the sound
quality will be improved and the system will be much easier to set up. In a typical active
sound system, the bass, middle and treble regions would each have their own speaker
drive units which would be wired directly to separate power amplifiers. The bass amplifier
would be the most powerful, the amplifier used for the mid range would be around half the
power of the bass amplifier and the treble amplifier would be around half to two thirds the
power of that of the mid range amplifier.
The active filter/crossover would be used to separate the two or three frequency bands at
line level immediately before the signal connects to the power amplifiers.
Some active filters have adjustable crossover frequency controls which can be useful
when testing the system to determine the most satisfactory frequency but care must be
taken to ensure that any final setting is within the speaker manufacturers specifications.
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NSTALLATION AND OPERATION MANUAL
Once the crossover frequencies have been determined, an active filter with fixed
frequencies determined by plug-in cards may be preferable for a fixed installation.
2.02 What are the optimum crossover frequencies?
A professional sound system should have a useful response from below 30Hz to above
20kHz but this overall response is a function of the design of the enclosures and the
placement within the building and is beyond the scope of this manual. Wherever possible
refer to the manufacturers specification for details of the crossover frequencies. Where no
specific details are available, there are practical guidelines which can be used to
determine the most suitable crossover frequencies for a particular system.
It is common to find multiples of 38cm and 45cm drivers used in low frequency
enclosures where the upper frequency limit of around 800Hz is dictated by a narrowing of
the dispersion and a loss of definition. The optimum upper limit is around 250Hz.
Where cone drivers are used for mid range purposes, the lower frequency limit should be
no lower than double the resonance of the drive unit and should be compatible with the
upper frequency limit of the bass drivers. The upper limit is again dictated by a narrowing
of the dispersion and loss of definition. For 30cm drive units the upper limit is 1.5kHz and
2kHz for 25cm units.
3
The high frequency section would normally use horn loaded compression drivers and
manufacturers data would have to be used to determine the most suitable crossover
frequency. A higher frequency than that specified by the manufacturer is often chosen to
improve the reliability of the compression driver's diaphragm. A system compressor/limiter
is also often used to prevent clipping of the power amplifiers output waveform which can
cause premature destruction of the diaphragm(s).
If compression drivers with horns are used to handle the high frequencies, it is common
practice to improve the ultra high frequencies by adding horn loaded tweeters to the same
circuit by using passive filters usually at frequencies above 5kHz.
2.03 Why 3 pole filters ?
When designing the CX2300, we were mindful of the requirement that the unit should
sound good. It is generally accepted that odd order filters sound more musical than their
even order counterparts and our own tests confirm this. The use of third order Butterworth
filters gives a high 18dB/octave roll off which relates to a power reduction of 85% per
octave.
3Installation
3.01 Installation notes for the experienced installation engineer
The Cloud CX2300 is a stereo three way active crossover designed primarily for use as
part of a professional sound system. The use of plug-in fixed frequency filter cards and
the supplied anti-tamper cover provides a high level of security and helps to preserve the
control settings and system reliability. The unit can be used in the two way mode if
required by using one filter card and positioning the PC mounted switch in the two way
mode (see section 4.01).
The CX2300 would normally have been supplied as a fully tested unit with the filter cards
fitted at the factory. For details of the crossover frequencies, see the documentation that
was supplied with the unit or alternatively, details are given on the plug-in cards.
For optimum performance and low noise operation, we strongly advise the use of
balanced interconnections with high quality XLR type connectors and two core screened
cables. If you experience low frequency 'hum loops' we suggest that you connect the
cable screen at the input end (amplifier) only and any common mode signal should be
rejected.
The CX2300 should be rack mounted close to the system power amplifiers but care
should be taken to avoid mounting the unit in close proximity to any power amplifier which
may radiate a high magnetic field from the core of its power transformer. It is good
practice to distance the line level wiring from the speaker wiring.
The CX2300 should be connected into the audio chain between the full range signal
processing equipment (such as mixers, equalisers and compressors etc) and the power
amplifiers.
When setting up the sound system, we suggest that the CX2300 level controls are set
before any other equalisation adjustments are made. The 20Hz high pass filter is
provided to protect speakers from excessive cone excursion in reflex enclosures but may
not be required if similar filters are present in other equipment (Cloud CXF & CXM mixers
have fixed 20Hz high pass filters).
3.02 Mounting
The CX2300 is designed for standard 19" rack mounting and occupies 1U of rack space.
Avoid mounting the unit directly above or below power amplifiers or power supplies that
radiate significant amounts of heat and strong magnetic fields. Fibre or plastic washers
may be used to prevent the front panel becoming marked by the mounting screws.
3.03 Audio Connections
Always use balanced interconnections wherever possible using high quality 2 core
screened cable. The wiring convention is: pin 2 hot (+ phase), pin 3 cold (- phase) and pin
1 signal ground. The shell of the XLR type connector is connected to the chassis (see
section 5.04 'Signal connections and EMC').
The CX2300 is designed as a stereo active crossover and the front panel controls and
internal circuitry operate as a two channel stereo device. If the audio system is configured
for mono operation, only one channel should be used.
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NSTALLATION AND OPERATION MANUAL
3.04 Schematic Diagram
5
3.05 Power connections
The unit will have left the factory configured to operate from a power input of 230V ?10%
at 40 to 60Hz. If the unit is required to operate from a 115V ?10% follow the following
instructions:
1 Disconnect the power lead from the power input connector.
2 Using a number 2 pozidrive screwdriver, remove the six self tapping screws
retaining the top panel of the unit.
3 Using a number 1 pozidrive screwdriver, remove the 5 M3 machine screws that
retain the PCB to the bottom panel. These can be located:
Adjacent to IC10.
Next to R33.
Near C16.
Two screws near the power transformer.
4 From the under side of the unit, remove the 6 self tapping screws retaining the
bottom panel, using the number 2 pozidrive.
5 If the unit is currently configured for 230V operation, one zero ohm link should be
fitted into the 230V position adjacent to the power transformer. Remove this link
and fit two links into the positions marked '115V'.
6 Change the power fuse to a T100mA type.
7 Mark the rear panel of the unit to indicate the revised input voltage and fuse
rating.
8 Re-fit the two covers and secure the PCB in reverse order.
3.06 Plug-in Filter Cards
Access to the filter card
1 Disconnect the power cable from the CX2300.
2 Using a number 2 pozidrive screwdriver, remove the six screws which retain the
top panel in place.
3 Locate the two plug-in cards mounted on the mother board. The low frequency
card is nearest the power transformer.
4 Remove the two M3 machine screws which hold the plug-in card in place, then
withdraw the card vertically.
5 Replace the card with care, ensuring that the mounting holes align perfectly with
the threaded mounting posts.
6 Replace the top panel.
4 Operation and Controls
4.01 Two Way Operation
Whilst the CX2300 will be used predominantly in the three way mode, the unit can be
used on two way systems. In this mode of operation, just one filter card, the low
frequency card, is used and the mode switch (mounted on the PCB) should be in the 'two
way' mode. LED's on the front panel indicate the mode of operation. When operating in
the two way mode, the high frequency output is used and the middle frequency output is
muted. The two bands are controlled on the front panel by the low frequency and middle
frequency sections with the high frequency section inoperative.
4.02 Do I use the 20Hz high pass filter ?
The ported reflex bass enclosure is used extensively in professional sound systems and a
characteristic of this design is that the cone of the LF driver is not loaded below the tuned
frequency of the enclosure and some form of excursion protection must be provided to
prevent the driver from possible physical destruction. The 20Hz high pass filter in the
CX2300 can be used to provide this protection at the rate of 18dB/octave. An additional
advantage of the filter is to help reduce acoustic feedback derived from turntable pickups
but only if the feedback occurs below 20Hz. Care must be taken to make sure that the
signal has not been processed by other filters in the signal chain (the Cloud CXM & CXF
mixers both have fixed 20Hz high pass 3 pole filters) unless double protection is desired.
4.03 The Invert Switch
It is often not practical to align the diaphragms and voice coils of the many drivers such
that they are all coincident and in addition, both equalisation and filter circuits can cause
small amounts of phase shift. The phase reverse switch will introduce a phase shift of 180
degrees and the most suitable position of the switch is best found by subjective tests
when the system is set up.
4.04 The Mute Switch
This facility would normally be used during initial testing/setting up or perhaps when fault
finding. Operating the mute switch will totally silence the respective frequency band on
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NSTALLATION AND OPERATION MANUAL
both left and right channel. Operating each band in isolation can be very revealing if you
wish to focus your attention on a particular driver(s).
4.05 The Gain Controls
All three bands have their own stereo gain control with a range of gain from a centre unity
position (0dB) to -12dB of attenuation in the anti-clockwise position and up to 6dB of gain
in the clockwise position. When setting up the sound system, all equalisation controls
should be in the flat position, including any Graphic Equalisers.
Using a pink noise source, the system should be set up using a spectrum analyser and
the level controls should be adjusted by leaving the LF gain in the centre (0dB) position
and adjusting the mid and HF gain controls to give a response as close as possible to a
falling response of around 3dB/octave as the frequency increases. Fine adjustments
should then be made via the system equaliser.
5 Circuit Description
5.01 Schematic diagram
7
5.02 The Audio Path
Both left and right input circuits feature an electronically balanced input stage with a gain
of -6dB which feed a bandpass filter with a switchable 20Hz highpass section and a fixed
50kHz lowpass filter. The filter output is routed to the 'in-phase' side of the phase invert
switches and the same signal is inverted and fed to the other side of the phase invert
switches. The output of these switches is connected to the three variable gain stages
including the mute switches. The low frequency section then routes the signal through the
low pass section of the low frequency card to the balanced output stage which has a gain
of 6dB. The mid frequency section feeds the signal through the high pass section of the
LF Card and then through the low pass section of the HF Card before reaching the
balanced output stage. The high frequency section uses the high pass section of the HF
Card and its balanced output stage.
5.03 The Power Supply
The CX2300 has a standard bi-polar 15-0-15 volt power supply derived from the two
adjustable regulators. This enables a smooth power-on as the circuitry has a slow rise
characteristic thus reducing power supply derived thumps and other extraneous signals
which often find their way on to the audio signal.
5.04 Signal Connections and EMC
The CX2300 is fully compatible with the Electromagnetic Compatibility standards and if
you propose to use the unit where it may be exposed to high levels of disturbance such
as may be found close to a TV or radio transmitter we suggest that the screen of the
signal cables should be connected to the chassis connection on the XLR type connector.
To avoid any ground loops, the signal earth (pin 1) should only be connected at the
receiving end of the cable when the common mode rejection should reduce any
unwanted signals to a negligible level.
5.05 The benefits of balanced interconnections.
Most professional audio equipment utilise balanced inputs and outputs using the familiar
3 pin XLR type connector or perhaps a 3 pole 6.3mm phone jack. A balanced output
stage will normally have a very low output impedance and will happily drive a line with a
load as low as 600Ω. The interconnecting cable should have two twisted cores with an
overall screen and any interference that may penetrate the screen would be picked up by
the two inner cores and appear as a common mode signal. The balanced input stage is
sensitive to differential signals only and features a high rejection of the common mode
signal (Common Mode Rejection or CMR) which may be interference or ground loop
hums. We therefore strongly suggest that balanced interconnections are used by default.
5.06 Using the CX2300 with unbalanced equipment.
The CX2300 can be used with any equipment with unbalanced signal ports. Where the
signal source is unbalanced, connect the signal ground to pins 1 & 3 and use pin 2 as the
hot signal input. This will result in no signal loss and will operate normally but without the
benefits of noise and interference cancellation.
If the output of the CX2300 is driving an unbalanced load, connect the screen to pin 1 and
the hot signal output to pin 2. Do not make any connection to pin 3 whatsoever. The
system will operate with a gain loss of 6dB which can be recovered by rotating the front
panel gain controls clockwise.
5.07 40Hz - the minimum frequency.
The circuitry of the CX2300 is arranged so that the mother board is fitted with two low
pass filters and two high pass filters which operate at the low frequency of 40Hz with no
plug-in card fitted. The filter cards are fitted with resistors which connect in parallel to the
resistors on the mother board and increase the operating frequency of the filters. The
minimum crossover frequency is therefore determined by the fixed 40Hz with no card
fitted and the practical upper limit is 8kHz.
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NSTALLATION AND OPERATION MANUAL
6 How to change the frequency of the filter card.
The frequency of the filter cards supplied with the unit will probably have been specified
at the time of ordering. If the frequency requires to be changed, please refer to the table
of resistor values in section 6.01. The filter card has a total of 24 resistors fitted but for
some frequencies not all 24 are required to be fitted.
It is important to make a note of the frequency on the card for future reference.
6.01 Table of resistor values for the filter card
Low Pass High Pass
9
Freq
R1 R3 R5
R20 22 24
R2 R4 R6
R19 21 23
R9 R16 R10 R15 R11 R18 R12 R17 R7 R14 R8 R13
40Hz No Card No Card No Card No Card No Card No Card No Card No Card
50Hz 1M6 2M4 1M2 ----- 620k 1M5 8M2 ----60Hz 910k 1M 1M2 1M2 220K 6M8 10M
70Hz 750k 560k 620k 1M1 220k 430k 5M1 5M6
80Hz 240k ----- 300k ----- 110k ----- 2M ----90Hz 330k 470k 240k ----- 130k 270k 1M6 ----100Hz 160k ----- 200k ----- 110k 220k 2M4 3M
110Hz 220k 360k 330k 360k 120k 130k 2M2 2M4
120Hz 120k ----- 150k ----- 110k 110k 1M ----125Hz 180k 300k 270k 300k 91k 120k 1M8 2M
130Hz 150k 360k 240k 300k 82k 120k 1M6 2M
140Hz 240k 160k 120k ----- 62k 150k 1M6 1M6
150Hz 130k 270k 110k ----- 62k 110k 2M7 1M
160Hz 160k 160k 100k ----- 62k 91k 1M2 1M5
170Hz 110k 220k 160k 220k 62k 75k 620k ----175Hz 160k 130k 160k 200k 62k 68k 1M1 1M3
180Hz 68k ----- 150k 200k 51k 82k 1M1 1M2
190Hz 110k 150k 160k 160k 56k 62k 910k 1M3
200Hz 120k 120k 150k 150k 43k 75k 1M 1M
210Hz 56k ----- 110k 200k 39k 75k 470k ----220Hz 130k 91k 120k 150k 47k 51k 750k 1M1
225Hz 120k 91k 110k 160k 39k 62k 430k ----230Hz 51k ----- 110k 150k 30k 100k 680k 1M1
240Hz 91k 100k 120k 120k 22k ----- 620k 1M1
250Hz 91k 91k 110k 120k 33k 56k 620k 1M
260Hz 68k 120k 100k 120k 20k ----- 510k 1M3
Low Pass High Pass
Freq
R1 R3 R5
R20 22 24
R2 R4 R6
R19 21 23
R9 R16 R10 R15 R11 R18 R12 R17 R7 R14 R8 R13
270Hz 110k 68k 91k 120k 24k 91k 560k 910k
275Hz 91k 75k 75k 160k 36k 39k 680k 680k
280Hz 110k 62k 100k 100k 30k 47k 560k 820k
290Hz 100k 62k 91k 100k 30k 43k 560k 750k
300Hz 82k 68k 75k 120k 30k 39k 620k 620k
325Hz 75k 62k 68k 110k 27k 36k 560k 560k
350Hz 62k 62k 39k ----- 27k 30k 390k 750k
375Hz 75k 47k 36k ----- 22k 33k 240k ----400Hz 56k 51k 56k 82k 22k 27k 390k 510k
425Hz 39k 68k 51k 82k 22k 24k 330k 560k
450Hz 47k 47k 51k 68k 18k 27k 390k 390k
475Hz 39k 51k 47k 68k 16k 27k 300k 470k
500Hz 33k 56k 43k 68k 16k 24k 240k 620k
525Hz 36k 43k 39k 68k 9k1 ----- 330k 330k
550Hz 27k 62k 47k 47k 15k 20k 220k 560k
575Hz 18k ----- 43k 47k 8k2 ----- 150k ----600Hz 33k 36k 43k 43k 13k 20k 270k 300k
625Hz 33k 33k 39k 43k 7k5 ----- 220k 360k
650Hz 30k 33k 39k 39k 13k 16k 130k ----675Hz 15k ----- 36k 39k 13k 15k 240k 270k
700Hz 22k 43k 30k 47k 12k 15k 220k 270k
725Hz 24k 33k 30k 43k 10k 18k 180k 330k
750Hz 27k 27k 30k 39k 6k2 ----- 180k 300k
775Hz 13k ----- 24k 51k 11k 13k 240k 200k
800Hz 24k 27k 30k 33k 11k 12k 200k 220k
900Hz 16k 36k 24k 33k 5k1 ----- 160k 220k
1kHz 10k ----- 20k 33k 9k1 9k1 120k 270k
1.1kHz 9k1 ----- 18k 30k 7k5 9k1 75k -----
1.2kHz 8k2 ----- 18k 24k 5k6 12k 130k 150k
1.3kHz 15k 15k 18k 20k 5k6 9k1 110k 150k
1.4kHz 11k 20k 16k 20k 6k2 6k8 75k 270k
1.5kHz 11k 16k 8k2 ----- 3k ----- 110k 110k
1.6kHz 10k 16k 15k 16k 5k6 5k6 91k 120k
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NSTALLATION AND OPERATION MANUAL
Low Pass High Pass
11
Freq
R1 R3 R5
R20 22 24
R2 R4 R6
R19 21 23
R9 R16 R10 R15 R11 R18 R12 R17 R7 R14 R8 R13
1.7kHz 9k1 16k 13k 16k 4k7 6k2 68k 160k
1.8kHz 8k2 16k 6k8 ----- 3k9 6k8 91k 91k
1.9kHz 6k8 22k 13k 13k 4k7 4k7 43k ----2kHz 8k2 12k 10k 16k 4k3 4k7 82k 82k
2.25kHz 8k2 9k1 10k 12k 2k ----- 36k -----
2.5kHz 3k9 ----- 8k2 12k 1k8 ----- 62k 68k
2.75kHz 6k8 7k5 7k5 11k 3k 3k6 56k 62k
3kHz 6k2 6k8 6k8 10k 1k5 ----- 27k -----
3.25kHz 4k7 8k2 7k5 7k5 2k2 3k6 39k 68k
3.5kHz 5k1 6k2 5k6 9k1 2k4 2k7 43k 51k
3.75kHz 3k9 7k5 ----- 6k2 1k6 4k7 43k 43k-4kHz 4k7 5k1 7k5 5k1 1k6 3k6 36k 47k
4.25kHz 3k9 5k6 3k3 20k 2k 2k2 30k 51k
4.5kHz 4k3 4k3 5k1 5k6 1k8 2 k2 18k -----
4.75kHz 3k9 4k3 5k1 5k1 1k6 2k2 27k 47k
5kHz 3k9 3k9 4k3 5k6 1k6 2k 16k -----
5.25kHz 3k 4k7 3k9 5k6 1k6 1k8 27k 36k
5.5kHz 3k 4k3 3k9 5k1 820R 68k 22k 43k
6kHz 1k6 ----- 2k ----- 1k1 2k2 27k 27k
6.5kHz 3k 3k 3k6 3k9 680R ----- 20k 33k
7kHz 2k4 3k3 3k3 3k6 1k1 1k5 22k 24k
8kHz 1k2 ----- 1k5 ----- 1k1 1k1 20k 20k
Note: All resistors are 1% tolerance unless marked * which denotes 5% tolerance.
With no card fitted, the filter operates at 40Hz.
7 Technical Specification
Frequency Response 20Hz – 20kHz ± 0.25db
Distortion (THD+N) 0.005% typ 20Hz - 20kHz 0dBu
Noise -91dB 22Hz - 22kHz RMS
-92dB A weighted
-90dB CCIR-ARM
Nominal input level 0dBu
Headroom 26dB
Input Impedance 10kΩ balanced - 5KΩ unbalanced
Common Mode Rejection -65dB / 10kHz
Crosstalk -70dB / 10kHz
Gain Range +6dB / -12dB
Sub-sonic Filter -3dB 20Hz 18dB/oct Butterworth
Crossover Filters 18dB/oct Butterworth
Nominal output level 0dBu balanced / -6dBu unbalanced
Minimum load impedance 600Ω
Maximium output level +26dBu balanced / +20dBu unbalanced
Power consumption 7.5 VA
Power requirements 230V ± 10% / 115V ±10% 40-60Hz AC
Fuse ratings 230V – T50mA 115V - T100mA
Dimensions Width 482.6mm (19" rack mtg)
Height 44.0mm (1U) Depth 175.0mm
Weight 3Kgs
This product conforms to the following European Standards
EN 50081-1: 1992
EN 50082-1: 1992
EN 60065 : 1994
SAFETY CONSIDERATIONS
CAUTION - MAINS FUSE
TO REDUCE THE RISK OF FIRE REPLACE THE MAINS FUSE ONLY WITH THE SAME
TYPE, WHICH MUST BE A CLASS 3, 240 VOLT, TIME DELAY TYPE, RATED AT 50mA
WHERE THE MAINS INPUT VOLTAGE IS SET TO 230 Volts ± 5% AC. FOR A MAINS
VOLTAGE OF 115 Volts ± 5% AC. THE FUSE SHOULD BE RATED AT 100mA
THE FUSE BODY SIZE IS 20mm x 5mm.
CAUTION - SERVICING
THIS UNIT CONTAINS NO USER SERVICEABLE PARTS. REFER ALL SERVICING TO
QUALIFIED SERVICE PERSONNEL. DO NOT PERFORM ANY SERVICING UNLESS YOU
ARE QUALIFIED TO DO SO.
WARNING
TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK DO NOT EXPOSE THIS
EQUIPMENT TO RAIN OR MOISTURE.
22/12/00
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