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Discussion in 'Amps and Cabs [BG]' started by isher1992, Jul 27, 2016.

  1. Well, I've got a used SVT-4 and I've been trying to use my dbx 166A with it, and I cannot get it to work whatsoever in the FX loop. I'm using TRS-XLR cables, and I put the send to the dbx input, then output from the dbx output to the FX Return B (Mono), and I get...nothing. No compression. It's like the loop is stuck in bypass, no matter where the switch on the front is. There's no footswitch connected, either. I've tried using unbalanced connections, and the compressor sees no audio. With TRS, it sees an input signal, but the amp does not use the FX loop. I've read through the manual time and time again, and I'm stumped.

    I connect from preamp output to power input using the compressor in the middle, and there's no signal through there either. These are brand new cables, and the compressor is functioning fine. Does anyone have any idea what's going on?
  2. BasturdBlaster


    Feb 19, 2012
    Crandon WI
    I really think that unbalanced cables should be used in either case but I wonder if this is a job for DeOxit but that's usually only needed when nothing is in the loop sockets, sorry isher92, I'm at a loss. Maybe the "effects bypass" button needs some DeOxit or maybe try pushing it in and out a bit to revive the contacts, just a thought..........or maybe the footswitch socket needs some DeOxit?
  3. The manual says to use a shielded instrument cable, which would be TRS.
  4. I haven't tried cleaning the bypass switch. It might be stuck in bypass mode.
  5. BasturdBlaster


    Feb 19, 2012
    Crandon WI


    Your typical Instrument cable (guitar cord) would be considered "shielded"

    A speaker cable is typically not shielded.
  6. Ah, I see now.

    I was over-thinking it. Regardless, the cables weren't the issue. The issue was the footswitch jack on the rear panel had somehow tricked the amp into thinking the effects loop is forever bypassed, regardless what the front switch does. Took some contact cleaner and a patch cable, some violent cable thrusts back and forth, twisting a bit and now it's fine.
  7. Primary

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    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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