Problem with my QSC rmx850

Discussion in 'Archived Threads 2001-2004' started by Chad_A, Aug 10, 2002.

  1. Chad_A

    Chad_A Auditioning

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    First off I'll admit that I'm a complete newbie when it comes to home audio, I've spend my years doing it all in the car till recently.

    I picked up a QSC RMX850 for my sub not thinking of the problems I may have with running Pro amp with consumer level inputs.

    Anyway my problem is that the amp clips very prematurely, I barely turn it up and it clips. I've tried running it from my receiver, a bookshelf system, and even direct from my soundcard just to see what was going on.

    I'm guessing the problem is I have too low of a signal voltage causing the amp to clip when I hardly turn the gain up at all. I've heard something about my problem being that I'm using consumer level outputs (-10db) on a pro amp with +4db inputs.

    If this is my problem what is the absolute cheapest way to fix this (I'm a college student and have an extremely tight budget). I've heard something about a Level Shifter then I was told a decent Direct Box would take care of the problem too....

    Can you point me in the right direction? (I'd love to spend $50 or less if at all possible)
     
  2. Eric Hargrove

    Eric Hargrove Stunt Coordinator

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    Chad,
    It sounds like you need an RCA sa-155 which will match the impedance of your receiver to the amp allowing you much more usuable gain. This can be found on ebay for less than $50. I belive Radio Shack might still carry it as well. A word of caution, this thing may add a bit of noise to your system. An SVS blackbox would be a better option but they are much more than $50. I am currently using an RMX2450 on my Ultra with no gain problems. Are you running bridged or stereo?
     
  3. Chad_A

    Chad_A Auditioning

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    I'm running bridged, 4 ohm to be exact. I can deal with a bit of noise for awhile just as long as I can use my sub, right now it's just bad enough to the point that I don't even bother turning the amp on.

    If the RCA will help me in this way would it help me if I just used the soundcard as a source (reason being I may need to go without a reciever for a few months but would still like to retain usability with the sub/amp.
     
  4. Eric Hargrove

    Eric Hargrove Stunt Coordinator

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    Not sure how the sound card would work compared to the sa-155. I guess you could give it a shot. I've seen the sa-155 sold on ebay for $20 or less though...
     
  5. Chad_A

    Chad_A Auditioning

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    I meant:

    Computer soundcard ->sa-155 -> qsc rmx850

    basicly cut out the reciever.
     
  6. John A. Gordon

    John A. Gordon Stunt Coordinator

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    Chad A,
    Have you resolved your problem? And, what is your exact set-up?

    John Gordon
    QSC Audio Products, Inc.
     

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