QSC SRA 1222 User Manual - Use-

32

LED indicators.

USE- 

Front Panel Controls and Indicators

Gain Controls

A gain control adjustment is provided for each

channel. The voltage gain of the amplifier (in dB)

is marked around each control.

Rotating the control clockwise increases the gain

applied to the signal. Rotating the control counter-

clockwise reduces the gain applied to the signal.

In stereo and parallel operating modes (see pages

14 through 16) each channel’s gain is adjusted by

its own control. In bridge mode, use channel 1’s

gain control and set channel 2’s control fully

counterclockwise.

Signal and Clip LED Indicators

SIGNAL- Illuminates when the input signal

strength is sufficient to drive the output above -30

dB relative to full output.

CLIP- Illuminates when the input signal strength

is strong enough to drive the output to the limits

of the power supply (i.e. clipping).

 • Normally, the clip LEDs will flash occasionally

when the amplifier is driven hard (high output

level).

• If Illuminated most of the time, the amplifier is

being driven extremely hard and may eventually

overheat, triggering the thermal shutdown circuitry.

• If fully illuminated, the amplifier is in thermal

shut down or short-circuit cutback is engaged.

Reduce the input signal strength; if the Clip LED

turns off, there is a problem with the speaker’s

wiring or one of the speakers. If the LED remains on

when input signal strength is fully reduced, the amp

is in thermal shutdown. Reduce gain settings or

input signal and allow the amp to cool down. Leave

the power on so that the fan continues to run;

operation will automatically resume after the

amplifier has cooled sufficiently.

Clip Indicator Tips

On the front panel, left side, is the Power switch.

The switch is labeled ON, above it and to the left.

To turn the power on: Press in on the upper

portion of the rocker switch. The amplifier will go

through its power-up cycle; the red-colored Clip

LEDs will illuminate briefly, then the green-

colored Power LED will remain on.

To turn the power off: Press in on the bottom

portion of the rocker switch. It may take a few

moments for the Power LED to extinguish. This is

normal.

If the Power LED fails to illuminate when the

power is switched on, check the power cord for

proper connection at both ends and verify the AC

power source is functioning properly.

AC Power Switch