KAM KXPro, KXPro1000, KXPro1600, KXPro2400 Instruction Manual

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KAM KXPRO AMPLIFIER

professional power amplifier

INSTRUCTION MANUAL

www.kam.co.uk

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KXPro 1000 and 1600 amplifiers require speakers with a minimum Impedance rating of 2 Ohm. KXPro 2400 requires 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 2, 4 and 8 Ohms.

FRONT PANEL CONTROLS

[1] Mains Power switch - use this to switch the mains power on/off. [2] Power LED - when the power is on the blue power LED will light. [3] Volume controls - used to adjust overall volume for each channel. [4] Channel Level Meters - each channel has a 12 point LED Level meter. AnoPtimum signal level

should cause these level meters to peak at between -6dB and 0dB.If the red 'Peak' indicator LED lights, signal levels are excessive and you should reduce the volume. [5] Stereo LED - this green LED illuminates when the KXPro is operating in standard stereo mode (IE the Bridge Mode switch [11] is set to STEreo. [6] Bridge LED - this green LED illuminates when the KXPro is operating in Bridge Mode(IE the Bridge Mode switch [11] is set to BRidge.

OVERVIEW

Your KXPro Amplifier is a high quality, high power professional PA amplifier with a wealth of features usually restricted to products with much higher price tags. It features built in adjustable Crossovers to facilitate use in complex audio systems and a robust design that makes realistic use of the dedicated Bridge mode connection a sensible proposition. 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 three models in the KXPro Amplifier range

KXPro1000 2 x 500W RMS amplifier KXPro1600 2 x 800W RMS amplifier KXPro2400 2 x 1200W RMS amplifier

SAFETY NOTE

ALWAYS turn off the mains power before making any connections to KX Pro 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.

WHICH SPEAKERS ARE RIGHT FOR YOUR AMPLIFIER?

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. A set of speakers has two stated ratings.

They should have a '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. This is often stated as two different ratings; 'RMS' which means how much power can be handled constantly… and 'Peak' which as the name suggests means an amount of power it can handle for a short period of time.

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 you may encounter 16 Ohm or even 2 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.

NOTE: Connecting multiple speakers to a single amplifier alters the impedance rating of the speakers. For guidance on this visit www.kam.co.uk/tuition.

KXPro1000

KXPro1600 KXPro2400 KXPro1000 Bridged KXPro1600 Bridged KXPro2400 Bridged

650W per channel

1000W per channel

n/a n/a n/a n/a

500W RMS per channel

800W RMS per channel 1200W RMS per channel 1200W RMS 2000W RMS n/a

300W RMS per channel

500W RMS per channel 750W RMS per channel 950W RMS 1400W RMS 2400W RMS

2 Ohm

4 Ohm speaker 8 Ohm speaker

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REAR PANEL CONTROLS

[7] Balanced XLR audio inputs - use these balanced XLR line level audio inputs to connect any line

level audio device such as a DJ Mixer, Mixing Console, CD player etc. For more information on the advantages of using balanced audio connections visit www.kam.co.uk/tuition. [8] Unbalanced 1/4” Jack audio inputs - use these unbalanced 1/4” Jack line level audio inputs to connect any line level audio device such as a DJ Mixer, Mixing Console, CD player etc. [9] Channel A&B speaker outputs - use these Speakon Type connectors to attach your speakers in normal stereo mode. KX Pro Speakon terminals are wired in a +2/-2 configuration. [10] Bridge Mode output - use this single (red) Speakon type connector to attach your speakers in Bridge Mode. Please read the 'Bridge Mode' section below before attempting to use Bridge Mode. [11] BR/STE switch - use this switch to choose between standard stereo operation (STE) and Bridge Mode operation. Please read the 'Bridge Mode' section below before attempting to use Bridge Mode. [12] Limiter switch - use this to switch the built in Limiter circuit on/off. When in the on position the audio signal will be automatically prevented from exceeding the maximum signal level beyond which clipping (distortion) will occur and the Peak LED will light. [13] Low Cut Filter controls - each channel features an adjustable Low Cut Filter designed to remove low frequency rumble etc to deliver an uncluttered low/mid sonic response. These controls are used to adjust the Cutoff Frequency and everything below the Cutoff Frequency is removed. The range is Off to 170Hz.

About Crossovers

The idea of a 'two way' speaker (which is what most 'full range' speakers are) is usually that the speaker cabinet houses two separate actual speaker drivers. It is common for one to be dedicated to reproducing High frequencies and the other to be dedicated to reproducing Low and Mid range frequencies. In order to make this work it is necessary to split the incoming audio signal in such a way that only High frequencies are sent to the High Frequency tweeter and only Low/Mid frequencies arrive at the Low/Mid driver. The device used to split the signal is called a 'Crossover'. It is common when assembling a more powerful PA system to have either a 'three way' system consisting of 3 separate speaker cabinets (1 each for Low, Mid & High frequencies) or a two way system where several full range speaker cabinets are augmented by an additional Sub or Bass speaker. In such set ups it is also necessary to employ Crossovers to divide audio signals so that the right PA system components receive only the right audio frequencies.

[14] Crossover Mode switches - the KXPro built in Crossovers are designed to be as versatile as possible and this Mode switch enables the selection of the correct configuration. Once the correct Mode has been chosen the Cutoff Frequencies are adjusted via the Crossover Frequency controls [15]. There are four Mode switch positions; BYPASS - the Crossover is inactive. HIGH - both Crossover Controls act as High Pass Filters so all frequencies above the selected Cutoff Frequencies are passed onwards to your speakers. Use this Mode when you wish to connect only a HF speaker. You may also wish to use the 'x10' switch [] to set the range of the Low /Mid Control to 500Hz-5kHZ. MID - The Low/Mid Control acts as a High Pass Filter. The Mid/High Control acts as a Low Pass Filter. Use this when you wish to connect a Mid range speaker cabinet. LOW - both Crossover Controls act as Low Pass Filters so all frequencies below the selected Cutoff Frequencies are passed onwards to your speakers. Use this Mode when you wish to connect only a LF speaker. [15] Crossover Frequency Controls - each channel has two controls that enable you to adjust the Cutoff Frequencies of the Crossover. Their function is determined by the setting of the Crossover Mode switches. [16] Ground Terminal - using an M4 screw to attach a ground cable from other equipment to this terminal can sometimes help eliminate 'ground loop' problems.

About Bridge Mode

Bridge mode is a professional feature that can seem simple but is actually fairly complex. 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… so you can only use Bridge Mode when using the balanced XLR input connection to channel A.

The next really important thing to know about Bridge Mode is that it can require a very unusual method of speaker connection with many amplifiers. Fortunately the KXPro provides a dedicated Bridge Mode Speakon output [10] so if you wish to use Bridge Mode connect your speaker to the red Bridge Mode output but do not connect any speakers to the stereo channel A&B outputs. If you require additional advice on using Bridge Mode with models of amplifier which do not feature a dedicated Bridge Mode output you will find it online at www.kam.co.uk/tuition.

You also 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).

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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. The KXPro has been designed to be happy in Bridge Mode providing you do not attempt to use a 4 Ohm speaker.

NOTE The Minimum speaker impedance for use with the KXPro in Bridge Mode is 8 Ohm.

About Thermal Protection Relay

KXPro amplifiers feature a thermally efficient central heat sink design and dual speed, dual 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 KXPro amplifier!

KXPro1000 power amplifier

Amplifier power output 500W RMS per channel @ 4 Ohms 300W RMS per channel @ 8 Ohms

Input connections Balanced XLR, unbalanced jack Output connections Speakon Minimum impedance 2 Ohms Frequency response 20Hz - 30KHz (±1dB) S/N Ratio 85dB THD 0.01% Soft Start AC/DC Protection Limiter Circuit Short Circuit Protection Thermal Protection 2 x dual speed cooling fans Min input sensitivity 770mv/0dB Input impedance 20k Ohm balanced & 10k Ohm unbalanced Dimensions 482 x 473 x 88mm Weight 19.5Kg

KXPro1600 power amplifier

Amplifier power output 800W RMS per channel @ 4 Ohms 500W RMS per channel @ 8 Ohms

KXPro2400 power amplifier

Amplifier power output 1200W RMS per channel @ 4 Ohms 750W RMS per channel @ 8 Ohms

Input connections Balanced XLR, unbalanced jack Output connections Speakon Minimum impedance 4 Ohms Frequency response 20Hz - 30KHz (±1dB) S/N Ratio 85dB THD 0.01% Soft Start AC/DC Protection Limiter Circuit Short Circuit Protection Thermal Protection 2 x dual speed cooling fans Min input sensitivity 770mv/0dB Input impedance 20k Ohm balanced & 10k Ohm unbalanced Dimensions 482 x 473 x 88mm Weight 23.5Kg