KAM KXR User manual

KAM KXR POWER AMPS
professional power amplifiers
INSTRUCTION MANUAL
www.kam.co.uk

OVERVIEW
Congratulations on your choice of new amplifier… cool isn’t it? We are certainly very proud of it. We
believe in giving you products with the features and performance you want at a price you can afford and the
KXR Amplifier range is living proof of our commitment to meeting that goal. We know you’re itching to get it
fired up but bear with us and we’ll run through a few things you should know that will help you get the best
from your new amplifier and ensure that it lasts as long as you want it to.
There are six models in the KXR Amplifier range
KXR150 150W RMS amplifier
KXR300 300W RMS amplifier
KXR600 600W RMS amplifier
KXR1000 1000W RMS amplifier
KXR1500 1500W RMS amplifier
KXR2000 2000W RMS amplifier
Although there are six different models in the range and some of them do vary slightly in input
configuration, the main difference between each model is their maximum power output. This means that
the basic principles of amplifier connection and usage are true for all six models. Below we outline basic
operation procedures and tell you about any differences that are particular to specific models.
SAFETY NOTE
ALWAYS turn off the mains power before making any connections to KXR amplifiers. Large PA amplifiers
are capable of sending potentially lethal amounts of electricity to their outputs so you should always
ensure that any amplifier has its power turned off (and preferably disconnected) before making
connections. NEVER attempt to connect a microphone to the speaker outputs of an amplifier.
CONNECTING SPEAKERS…
WHICH SPEAKERS ARE RIGHT FOR YOUR AMPLIFIER?
Passive only
Your KXR Amplifier is designed to be used in conjunction with a set of passive speakers. This means that
they’re good for use with most (providing you follow the rating and connection procedures below) speaker
types that don’t have built in amplification; in the context of the Kam equipment range this means your
KXR amplifier is ideal for use with our IMS Pro10, IMS Pro12 & IMS Pro15 speakers (or our standard
IMS or Z Series speakers) but it is not needed with our IMS Pro12A or IMS Pro15A ‘active’ speakers
because they already have built in amplification.
Power & Impedance
It is important to ensure that you match the power that your speakers can handle with the power that
your amplifier can produce.
Speaker Rating
A set of speakers has two stated ratings.
They should have a maximum power handling capacity that is measured in Watts (EG 300W). This tells
you how much power the speaker can handle from the amplifier before the sound distorts and damage
begins to occur.
A speaker will also have what we call an ‘Impedance’ rating. Impedance is a term we use to define the
amount of resistance your speaker presents to your amplifier and it is measured in ‘Ohms’. Most
speakers have an Impedance rating of 8 Ohms but ratings of 4 Ohms are not uncommon and sometimes
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you may encounter 16 Ohm. A speaker that is rated at 8 Ohm presents a larger amount of resistance to
the amplifier than one that is rated at 4 Ohm. As you can see from the chart below this means that a
particular amplifier will deliver greater power to a pair of 4 Ohm speakers than it would to a pair of 8
Ohm speakers.
KXR amplifiers require speakers with a minimum Impedance rating of 4 Ohm. They will work just as well
with speakers rated at 8 Ohm but the volume achieved from your speakers will be different for 4 and 8 Ohm
speakers. The chart below tells you the power output ratings for KXR amplifiers at both 4 and 8 Ohms.
4 Ohm speaker 8 Ohm speaker
KXR150 75W RMS per channel 50W RMS per channel
KXR300 150W RMS per channel 100W RMS per channel
KXR600 300W RMS per channel 200W RMS per channel
KXR1000 500W RMS per channel 340W RMS per channel
KXR1500 750W RMS per channel 450W RMS per channel
KXR2000 1000W RMS per channel 670W RMS per channel
CONNECTING YOUR SPEAKERS TO YOUR AMPLIFIER…
• Always ensure that both volume controls on your KXR amplifier are turned to zero and
that it’s mains power is switched off when making connections.
• Using an appropriate cable (if in doubt refer to the ‘Connection types’ section below)
connect the left speaker to channel A and the right speaker to channel B.
• Please read the rest of this manual before turning on the power or adjusting the volume
controls.
CONNECTION TYPES
Speakon
All KXR amplifiers feature a pair of Speakon speaker output sockets. Speakon is a standard connection
type that is only used for connecting speakers to amplifiers. You cannot use Speakon connections for any
other type of audio signal connection.
The Speakon connections on your KXR amplifier are internally wired with a standard +1/-1 configuration.
This means they are designed to be used with two pin Speakon cables. This wiring configuration matches
all Speakon equipped Kam speakers. If you wish to use your KXR amplifier with speakers which use a
+2/-2 configuration you may need to construct a special cable. You will find details on this and how to
construct a standard Speakon cable online at www.kam.co.uk/tuition.
Binding Posts
Although Speakon is a safer and more reliable form of speaker connection and we highly recommend using
Speakon if you can… for your convenience you will find that all models of KXR amplifier also feature
‘Binding Post’ speaker output connectors. Binding Posts are threaded terminals designed to accommodate
bare wires. For secure connection pass the bare cable end through the hole, wrap the cable around the
post and firmly screw down the cap. It is important to ensure that no stray bare cable ends connect the
two posts. One post is red and should be used for positive and the other is black and should be used for
negative connections.
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BRIDGE MODE OPERATION
The following KXR amplifiers feature Bridge Mode Operation; KXR600, KXR1000, KXR1500 & KXR2000.
Bridge mode is a professional feature that is actually fairly complex.It is a means of devoting the entire
power of your amplifier to a single audio input. But you cannot simply connect a single speaker to one
channel output and use it… it requires a very unusual wiring configuration and very solid understanding of
speaker impedance and power handling. Unless you really know what you are doing with it, don’t use it.
We’d better explain… in bite-sized pieces;
• Bridge mode devotes the entire power output capacity of the amp to the Channel A input.
• That may sound simple but the way in which the amplifier achieves this is not so simple.
• If you understand how a balanced audio connection works you’ll know that it provides three
wires within an audio cable; one of them is simply an earth, the other two each carry half of the audio
signal – one carries the positive half of the signal and the other carries the negative half.
• When you place an amplifier in bridge mode, it uses channel A to amplify the positive half
of the signal and uses channel B to amplify the negative half of the signal.
• So the first thing to understand about bridge mode is that you can’t use it with an
Unbalanced audio input.
• This also has a dramatic effect on how you connect your speakers to the amplifier.
• With a pair of Balanced audio connections in normal operation, the two polarities of the
signal (within each individual Balanced connection) are amplified within each channel of the amp (with
the two channels of the amplifier operating in parallel)… so both channels of the amplifier
accommodate a connection each and are basically doing the same thing at the same time.
• In bridge mode, because each side of the amplifier is now being fed by one input but
dealing with opposite polarities of the audio signal, they are no longer doing the same thing at the
same time… when channel A is ‘sucking’, channel B will be ‘blowing’.
• This means that if you leave a pair of speakers connected in the normal manner, one
speaker will only be getting the positive half whilst the other speaker will only be getting the negative
half of the audio signal.
• What is worse is that the amplified signals are only delivered to just one (the positive)
terminal of each output channel of the amplifier (sorry we did say it wasn’t simple).
• The amplifier will continue to attempt to drive the speakers just as hard but the entire
thing will be messed up and sound dreadful.
• The answer is to connect a single speaker across both channels of the amplifier.
• This means that with KXR amplifiers you cannot use the Speakon outputs in bridge mode.
• With KXR amplifiers you need to use the Binding Posts to connect a single speaker.
• Connect the positive wire of your speaker cable to the positive Binding Post of channel A.
• Connect the negative wire of your speaker cable to the positive Binding Post of channel B.
The problems don’t end there either. You need to be aware that bridge mode potentially delivers
considerably more power to your speakers. In much the same way that attempting to use an over
powered amplifier to drive an under sized speaker is obviously a recipe for trouble… so is trying to use
bridge mode to coax more volume from low impedance speakers. Bridge mode can be useful for using an
amplifier to drive a speaker with a higher impedance than usual (perhaps driving a single 16 Ohm speaker
with an amplifier you might use to drive a pair of 8 Ohm speakers). But this has it’s own problems
because a higher impedance speaker will actually demand more power from your amplifier (even at lower
volumes) than it is used to delivering to a lower impedance speaker… and that can over strain your
amplifier.
Bridge Mode is activated by pressing the recessed switch (you will need a small screwdriver or other
similar implement to reach it) marked ‘Bridge’ which is located near the volume controls on the front
panel. When activated the accompanying LED beside the switch will illuminate.
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CONNECTING MIXERS ETC…
Which equipment is right for your amplifier?
All audio input connections on all KXR Amplifiers operate strictly at Line Level. This means that, providing
you have an appropriate cable, you can connect any Line Level audio device to the input connections on the
back of your amp’. For most circumstances this means using a mixer… this can be a DJ mixer or a
mixing console of the type used to combine various instruments when mixing a live band etc. In some
circumstances you might wish to connect a CD, MP3, DAT, Cassette Player etc or any other line level
device directly to the Line Input connections and this should work quite safely… but it is more common to
use a mixer of some sort to enable you to combine several sound sources and to provide additional overall
volume control. Your amplifier IS NOT designed to accept input connections directly from microphones. If
you wish to use a microphone you’ll need to connect the microphone to a mixer (so that the mixer can
convert the Mic Level signal to a Line Level signal) and then connect the mixer to your amp’.
Connection types
Balanced XLR. All models of KXR amplifier feature line level balanced XLR audio input sockets. If your
equipment features appropriate balanced XLR audio outputs and you have an appropriate cable we
recommend using this connection type.
Unbalanced Jack. All KXR amplifiers also feature unbalanced Jack input sockets.
Line Level RCA Phono. Two models of KXR amplifier feature line level RCA Phono input connections; the
KXR150 & KXR300. This is simply because these two models of amplifier provide a power output level
that it suited to home use or for performances in bars etc. RCA Phono is a domestic audio connection
type. It is important to note that these are Line Level RCA Phono connections… NOT ‘Phono’ Level RCA
Phono connections. This means you cannot connect the output from a standard turntable (unless your
turntable has a built in pre-amplifier and specified line level RCA Phono outputs). You must connect a
standard turntable to a DJ mixer (or other appropriate pre-amplifier) so that the mixer can boost the
‘Phono Level’ turntable output signal to the ‘Line Level’ that is right for your amplifier.
PROCEDURE
• Always ensure that the volume controls on your KXR amplifier are turned to zero and that
it’s mains power is switched off when making connections.
• If you look at the output connections on your mixer etc you should see that there are two
sockets, one marked ‘left’ or ‘L’ and the other marked ‘right’ or ‘R’.
• Almost all mixers will also colour code all of the audio input and output connections using
a simple rule; Red = Right, White = Left. If you purchase a commercially produced audio cable you will
often find that the connectors are colour coded to help you follow the rule.
• Use an appropriate audio cable to connect the left channel of the output from your mixer
to the input marked channel A on your amplifier… and connect the right channel of the output from
your mixer to the input marked B on your amplifier.
• If you have already connected up your speakers you are ready to move on to turning on
and using your equipment.
ALWAYS TURN ON YOUR EQUIPMENT IN THE FOLLOWING ORDER;
1. Turntables, CD players etc – but don’t start playing any music yet
2. DJ mixer (if you use one) – but make sure that the output volume is at zero
3. KXR amplifier
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NOW YOU ARE READY TO PLAY SOME MUSIC;
1. Put on a record, slide in a CD etc and start it playing
2. If you use a mixer, use it to set up optimum input and output signal levels – the level
meter should be peaking at around zero dB
3. Slowly turn up the volume controls on your KXR amplifier – if you have used the right
cables and made all of your connections correctly you should clearly hear music.
4. If you do not hear any music or it sounds all wrong, even at low volumes, check all your
connections and cables.
5. When the music reaches the desired listening level, stop turning up the amplifiers volume controls.
6. KXR amplifiers are designed to deliver professional quality sound reproduction and plenty
of power but it is possible to overload them. All KXR amplifiers feature ‘Signal Clip Indicator’ LEDs on
the front panel just above the volume controls. These LEDs illuminate when the incoming signal level
exceeds the safe operating level. It is acceptable for these LEDs to illuminate occasionally during
normal usage, however the gain structure of all KXR amplifiers has been carefully set so that these
LEDs serve as a genuine indication of overload… so if they come on frequently you are in danger of
damaging your amplifier and probably your speakers too.
• Sending excessive signals from your external equipment to your KXR amplifier will cause a
distorted sound and can damage your amplifier and/or speakers. Kam products which have been
damaged in this way are not covered by your guarantee.
• Your KXR amplifier is guaranteed against manufacturing defects but it is not guaranteed
against accidental user damage or normal wear and tear.
Ground Lift Switch
When using Unbalanced audio input connections you may, in some circumstances experience problems
with persistent hum. This can be caused by an ‘earth/ground loop’. To help combat this all KXR amplifiers
have a ‘ground lift’ switch on the rear panel. This switch disengages the ground (aka earth) connection
from the mains power to the amplifier. The problem is rare with correctly configured Balanced audio
connections.
Thermal Protection Relay
All KXR amplifiers feature a thermally efficient central heat sink design and forced fan cooling. They are
designed to operate in the kind of relatively high environmental temperatures found in some venues and
we feel that they perform extremely well in such hostile conditions. However, because extremely high
environmental temperatures are always a hazard to high power amplifiers, all KXR amplifiers also feature
a Thermal Protection Relay. If the amplifier becomes too hot, it will temporarily go into a ‘standby’ mode
where the audio circuitry (but not the fans!) is switched off. This gives the circuitry time to cool down. If
this happens the amber LEDs marked ‘Protect’ (found on the front panel above the volume controls) will
illuminate. If this happens you should turn the volume controls to zero immediately and wait. When the
Protect LEDs stop being illuminated you can gradually return the volume controls to the desired listening
level. Under such circumstances it is advisable to return the volume controls to a slightly lower listening
level than that set prior to the engagement of the Thermal Protection Relay. The more power output you
demand from your amplifier, the higher the internal operating temperature is liable to be… so a lower
listening level will decrease the chances of the Relay engaging once more.
You will find loads more advice and information about setting up Kam audio equipment within the Tuition
area at www.kam.co.uk.
Thank you for reading these guidelines and enjoy your Kam KXR amplifier!
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KXR15 0 power amplifier
Amplifier power output 75W RMS per channel @ 4 Ohms
50W RMS per channel @ 8 Ohms
Input connections Balanced XLR, unbalanced jack & RCA phono
Output connections Speakon & binding post
Minimum impedance 4 Ohms
Frequency response 20Hz - 30KHz (±1.5dB)
S/N Ratio 85dB
THD 0.05%
Dimensions 316 x 88 x 481mm
Weight 6.5Kg
KXR300 power amplifier
Amplifier power output 150W RMS per channel @ 4 Ohms
100W RMS per channel @ 8 Ohms
Input connections Balanced XLR, unbalanced jack & RCA phono
Output connections Speakon & binding post
Minimum impedance 4 Ohms
Frequency response 20Hz - 30KHz (±1.5dB)
S/N Ratio 90dB
THD 0.05%
Dimensions 316 x 88 x 481mm
Weight 7Kg
KXR600 power amplifier
Amplifier power output 300W RMS per channel @ 4 Ohms
200W RMS per channel @ 8 Ohms
Input connections Balanced XLR & unbalanced jack
Output connections Speakon & binding post
Minimum impedance 4 Ohms
Frequency response 20Hz - 30KHz (±1.5dB)
S/N Ratio 84dB
THD 0.1%
Dimensions 341 x 88 x 481mm
Weight 10Kg
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KXR1000 power amplifier
Amplifier power output 500W RMS per channel @ 4 Ohms
340W RMS per channel @ 8 Ohms
Input connections Balanced XLR & unbalanced jack
Output connections Speakon & binding post
Minimum impedance 4 Ohms
Frequency response 20Hz - 30KHz (±1.5dB)
S/N Ratio 84dB
THD 0.1%
Dimensions 341 x 88 x 481mm
Weight 12Kg
KXR1500 power amplifier
Amplifier power output 750W RMS per channel @ 4 Ohms
450W RMS per channel @ 8 Ohms
Input connections Balanced XLR & unbalanced jack
Output connections Speakon & binding post
Minimum impedance 4 Ohms
Frequency response 20Hz - 30KHz (±1.5dB)
S/N Ratio 90dB
THD 0.1%
Dimensions 416 x 88 x 481mm
Weight 18Kg
KXR2000 power amplifier
Amplifier power output 1000W RMS per channel @ 4 Ohms
670W RMS per channel @ 8 Ohms
Input connections Balanced XLR & unbalanced jack
Output connections Speakon & binding post
Minimum impedance 4 Ohms
Frequency response 20Hz - 30KHz (±1.5dB)
S/N Ratio 90dB
THD 0.1%
Dimensions 416 x 88 x 481mm
Weight 18.5Kg
KXR POWER AMPLIFIERS
www.kam.co.uk
© COPYRIGHT LAMBA plc 2004. Due to continuous product development, specifications are subject to change. E&O E.