Bob@QSC amp question...

Discussion in 'Amps and Cabs [BG]' started by steveksux, Aug 3, 2005.

  1. Hey, Bob.... and anyone else with 2c worth to add...

    I've got a QSC 1300, one channel doesn't work in stereo, but when I put it in bridge mode, both channels work. I hooked speakers up to the normal output terminals in bridge mode as a test to make sure both output channels were really putting out signal. They were.

    So I'm thinking its in the input stages of the one channel malfunctioning, maybe the volume pot, maybe wiring, maybe jack, but whatever it is has to be before the inverted signal from the first channel is injected into the signal path of the second channel to make it work in bridge mode.

    Make sense? I'm hoping its something simple, maybe tuner cleaner on the pot, or loose wire a soldering iron will fix. If my analysis is correct, I'll crack the case and take a look.

  2. MJ5150

    MJ5150 Terrific Twister

    Apr 12, 2001
    Lacey, WA
    Have you tried sending him a PM?

  3. Not yet, maybe I'll try that. He's usually lurking a lot, figured he'd spot it. I could probably get auth service locations from their web site too.....

  4. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Hi Randy,

    Yes, I agree with your reasoning so far; it appears to be a fault in the input circuitry. Send me an e-mail at and I'll send you a PDF of the USA 1300 schematic.