I have a JBL CSMA 1120 drivecore which features a power-saving mode, switching off after 30 minutes. The power-saving can be de-acticated by signal return on inputs and I need an advice how to wire that — the inputs are balanced (XLR jack on the panel, terminal block on the amp), and the euro-block has 3 pins, as expected: hot, cold, ground. Is by "return of signal" meant simply to connect either of the active conductors to ground, and then if there is > -40dBu on the line, it will wake the device up?

The pictures below are respectively from pages 23 and 9 of the Operation manual

screenshot from the manual

back panel input pins

1 Answer 1


I would read return of signal as the presence of an audio signal on any input (well, a signal above -40 dBu).

There seem to be an alternative to wake up the amplifier from sleep mode which is to short two pins of one of the the priority input connector.

  • 1
    Just presence of signal from the signal does not seem to wake it up when the speaker speaks (the input level is maxed). What you say about priority pin is correct, though it mutes all other inputs, which is not desired in that particular set-up. Thanks anyway, I will experiment a bit more.
    – eudoxos
    Commented Jul 11, 2022 at 6:05
  • 2
    It is possible that the output of a mic is lower than -40 dBu, so too weak to wake up the amplifier. It's not clear whether this threshold is measured before or after amp input gain, but it well maybe before.
    – audionuma
    Commented Jul 11, 2022 at 17:55

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