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1. AC power socket - Once you have completed all connections to the amplifier, plug the AC power cable into an appropriate mains socket then switch on. Your amplifier is now ready for use.

2. RS232C - RS232 is a standard serial data communication protocol, which allows devices that support RS232 to communicate with each other as part of a home automation system.

Custom install control - a full protocol is available for the CXA on our website here.

3. Control bus - RCA sockets used to send and receive power and volume commands from other connected CX Series products. For more information on the Control Bus, see 'Control Bus' section.

4. IR in  - Allows modulated IR commands from an IR repeater or custom install systems to be received by the amplifier. Commands received by the IR In socket are not looped out of the Control Bus.

Note: The IR input doesn’t provide any power, so any device connected to this input will need to have its own power source.

5. Trigger in/out - The CXA can be connected to the trigger control output of home automation equipment to control the power state of the CXA. The input level should be 12V.

The trigger out provides a continuous 12v, this is active while the CXA is powered on. This can be used to turn on other equipment that has a trigger in.

6. Speaker terminals

Note: When using a banana plug, make sure the speaker terminals are completely tightened before inserting the plug. 

CXA banana plug

Two sets of loudspeaker terminals are available:

A (main loudspeaker terminals)


B (secondary loudspeaker terminals).

Connect the wires from your left channel loudspeaker to the left terminals on the CXA, and the wires from your right channel loudspeaker to the right terminals on the CXA.

Always ensure that the positive connection on the amplifier is connected to the positive connection on the speaker and the negative connection on the amplifier is connected to the negative connection on the speaker.

The Red terminal is the positive output.

The Black terminal is the negative output.

Care should be taken to ensure no stray strands of wire short the speaker outputs together. Please ensure that the loudspeaker terminals have been tightened completely to provide a good electrical connection.

It is possible for the sound quality to be affected if the screw terminals are loose.

Note: The speaker terminals will need to have the round pips removed before you can insert a banana plug into them.

7. Sub out - Connect to the input on an active subwoofer, if required.

Note: There is a low pass filter of approximately 2.3 kHz applied to the Sub Out, no frequencies above 2.3 kHz will be sent to a subwoofer connected to this output. This is so that there is minimal phase added by the CXA at the Sub Out frequencies. 

The crossover frequency can be adjusted on the Subwoofer itself.

8. Pre-out - For connection to the unbalanced inputs of a power amplifier or active subwoofer.

Note: There is not a low pass filter applied to the Pre-Out, so the full frequency range will be sent to a subwoofer connected to the Pre-Out.

9. Bluetooth antenna - Used for Bluetooth audio streaming. See 'Bluetooth' section for details.

10. Analogue inputs (A1 Unbalanced, A2, A3 and A4) - Suitable for any 'line level' source equipment such as CD players, DAB or FM/AM tuners etc.

These inputs are for analogue audio signals only. They should not be connected to the digital output of a CD player or other digital devices.

Note: For the balanced XLR inputs, pin1 is ground, pin2 is positive and pin3 is negative.

11. USB audio in - A USB B type socket to enable the playback of audio from a computer running either Microsoft Windows or Apple Mac OS X operating systems. Some builds of Linux are also suitable.


  • Always use a high-quality USB connection cable certified as USB Hi-Speed. USB cable connections longer than 3m may result in inconsistent audio performance.
  • Always turn the volume to minimum, switch to another input or turn the CXA off before plugging/unplugging cables to the USB input or whilst booting up/shutting down your PC/Mac.

Ground/Lift switch - The Ground/Lift switch enables the USB interface earth to connect or disconnect the CXA signal ground. Disconnecting (lifting) the earth can be useful if electronic hum is heard through the speakers when the USB input is selected. The switch should otherwise be left in the Ground position.

12. Digital inputs (D1, D2 AND D3) - TOSLINK and S/P DIF co-axial digital inputs.

Coaxial – Use a high quality 75 ohm digital RCA Phono interconnect cable (not one designed for normal audio use). This input is suitable for 16-24 bit content up to 192kHz.

TOSLINK optical – Use a high quality TOSLINK fibre optic interconnect cable designed specifically for audio use. This input is suitable for 16-24 bit content up to 96kHz (TOSLINK is not recommended at 192kHz sampling rates).

Note: To obtain the best results from your system we recommend using only high-quality Cambridge Audio interconnects. This will ensure that you hear your system as we designed it. Please ask your dealer for details.

13. A1 inputs

Note: Balanced (XLR) is available on the CXA81 only.

A1 inputs feature either unbalanced (phono/RCA) or balanced (XLR) connections. The balanced connection is the higher quality option and can reject noise and interference in the cable when used with other equipment that supports this function.

An XLR connector is wired Pin 1 - Ground; Pin 2 - Hot (in-phase); Pin 3 - Cold (phase-inverted).