Connections

Inputs

Each channel has active balanced XLR and ¼" (6.3 mm) inputs wired in parallel (Figure 22). The input impedance is 20 kΩ balanced, 10 kΩ unbalanced.

Balanced signals are less prone to AC hum, but unbalanced signals can be suitable for short cable runs. The signal source’s output impedance should be less than 600Ω to avoid high frequency loss in long cables.

Balanced Inputs

Use the XLR or ¼" (6.3 mm) TRS input jacks, or the barrier strip (Figure 25).

Unbalanced Inputs:

Connect the unused side (Pin 3) of the balanced input to ground (Pin 1), as shown in (Figure 23).

A tip-sleeve ¼" (6.3 mm) connector will correctly terminate the unused side of the input ( Figure 26).

For Stereo operation, use the inputs for both Channel 1 and Channel 2. For Parallel or Bridge Mono operation, use the Channel 1 input.

See the section on operating modes for more information. To patch the audio signal to other amps (Parallel and Bridge Mono modes only), see the instructions for using Parallel Inputs on page 6.

Or

XLR unbalanced

 

Jumper pin 1 to pin 3

Pin 1 = Ground

 

 

 

 

 

Pin 2 = +

 

 

Pin 3 = -

– Figure 22 –

– Figure 23 –

TRS unbalanced

No modification needed

– Figure 24 –

Balanced

Unbalance

ground

ground

 

inverting Input

 

non-inverting input

non-inverting input

– Figure 25 –

– Figure 26 –

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QSC Audio CMX 300V, CMX 800V, CMX 500V user manual Connections, Inputs