Q240

Q Series Stereo Power Amplifiers

172.051UK

Introduction

Thank you for choosing the QTX Q series power amplifiers as part of your sound reinforcement system. These amplifiers are designed to offer high quality, dependable service for mobile and installed systems. Please read this manual fully and follow the instructions to achieve the best results with your new purchase and to avoid damage through misuse.

Warning

To prevent the risk of fire or electric shock, do not expose any of the components to rain or moisture.
If liquids are spilled on the casing, stop using immediately, allow unit to dry out and have checked by qualified personnel before further use. Avoid impact, extreme pressure or heavy vibration to the case
No user serviceable parts inside – Do not open the case – refer all servicing to qualified service personnel.

Safety

Check for correct mains voltage and condition of IEC lead before connecting to power outlet
Ensure speaker leads are good condition with no short connections or damaged plugs
Check impedance of speaker loads do not exceed the minimum stated load for the amplifier
Do not allow any foreign objects to enter the case or through the ventilation grilles

Placement

Keep out of direct sunlight and away from heat sources
Keep away from damp or dusty environments
When rack-mounting, ensure adequate support for the base of the amplifier and firm fixings for the front
Ensure adequate air-flow and do not cover cooling vents at the front and rear of the amplifier
Ensure adequate access to controls and connections

Cleaning

Use a soft cloth with a neutral detergent to clean the casing as required
Use a vacuum cleaner to clear ventilation grilles of any dust or debris build-ups
Do not use strong solvents for cleaning the unit

Unpacking

Your QTX Q series amplifier should arrive in good condition with the appropriate mains IEC lead(s) If any contents are missing or damaged, contact your dealer immediately.

Layout

Cooling vents – do not cover
LED Clip indicators
Channel gain controls
Power on/off switch and LED
LED Signal indicators
IEC mains inlet and fuse holder
Voltage selector
SPK speaker outputs
4mm binding post speaker outputs
6.3mm jack speaker outputs
| L+R line inputs (6.3mm jack)
L+R line inputs (RCA)
Cooling fan – do not cover

Operation

Connect speaker cabinets to speaker outputs (8, 9 or 10) using good quality leads and ensure that the combined load on each channel is no lower than 4Ω (for speaker loads connected in parallel, 8Ω + 8Ω = 4Ω) Connect each signal input from mixer or other line level source via the jack (11) or RCA (12) connectors on the rear panel using good quality signal leads. The jack and RCA inputs are wired in parallel, so whichever is not used for the input signal can be used to connect onto further amplifier inputs.

Connect the amplifier to the mains outlet, making sure that the IEC lead is earthed, in good condition and connected securely. Ensure the correct voltage is selected on the rear panel voltage selector (7)

With channel gain controls (3) turned fully down, switch the power switch (4) on.

With mixer (or other signal source) levels turned down, gradually increase the amplifier’s channel gain controls to the required level (normally full) and then gradually increase the signal level from the mixer or sound source until sound can be heard through the speakers and then continue increasing up to the required level.

During use, the Signal LEDs (5) will illuminate to show that the signal is present. If the Clip LEDs (2) illuminate more than very briefly, reduce the volume until they hardly light up at all. This will avoid distortion or “clipping” through the speakers.

Before powering down, turn the channel gain controls fully down to avoid loud noises when switching off.

Troubleshooting

Issue	Solution
No power light on front panel switch	Ensure IEC inlet is connected to mains and lead is in good condition
	Ensure mains outlet is switched on
Power light is on but no other LEDs and no output	Check input signal and connection leads
	Ensure channel gain controls are not turned fully down
Power light and Signal LEDs are lit but no output	Check speakers are in good working order and not shorted (use a multi-tester)
	Check speaker leads are in good condition and connected properly
	If speakers/leads OK, switch off again and refer to qualified service personnel
Case getting hot	Ensure cooling vents are clear and fan is working (refer to technician if not)
Output is very distorted and CLIP LEDs are lighting	Check the speaker impedance is not below the rated Ohms
	Turn down the input level from audio source
	Turn down channel gain controls
Output is working but at very low level	Ensure input source is at line level
	Increase input level from audio source
	Turn up channel gain controls

Precautions

Indoor use only : The "House" symbol identifes electrical equipment designed primarily for indoor use.

Disposal : The "Crossed Wheelie Bin" symbol on the product means that the product is classed as Electrical or Electronic equipment and should not be disposed with other household or commercial waste at the end of its useful life. The goods must be disposed of according to your local council guidelines.