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QSC power amp to speaker box question

Discussion in 'Amps and Cabs [BG]' started by bluebyrd, May 17, 2003.

  1. bluebyrd


    Jun 12, 2000
    I can't search because the search function isn't working at the moment.

    I just bought an Avatar CB 115H cab. Nice cab for only $267 delivered. It sounds great thru my Peavey TNT115 combo. In that configuration the entire rig is only 200 watts. The CB115H is rated at 600 watts at 4 ohms. Will running it this way damage the Avatar cab? It sounded very good last nite, but I only had a chance to try it out for about an hour. That Avatar cab is great for the price!

    Also, I'm looking at the QSC RMX series of amps. They are in my price range, and the PLX series is just too expensive for me at this time. I was looking at the RMX 850 primarily. Does anyone know if this can be hooked up to a cab with two 1/4 inch jacks? Or does the pre-amp go to the cab? Sorry for the dumb questions, but I'm new at the preamp/power amp thing. If it gets too complicated, maybe I'll just try for something like a Peavey Firebass head or something similar.

    Anyway, thanks for any help. I wish the search function worked! I miss it.

  2. chucko58


    Jan 17, 2002
    Silicon Valley, CA, USA
    I paid for all my gear myself. Well, me and MasterCard.
    You're unlikely to hurt your Avatar cab by under-powering it.

    The RMX amps are great, if a bit heavy. You would need to buy or make a cable to go from the QSC's Speakon or banana outputs to your cab's 1/4" input. With just one cab, I'd go with a banana myself; it's trivial to switch from mono to bridged that way, just flip the banana plug down to the bridged outputs. The RMX 850 would be a very good match for your cab in bridged mode.
  3. bluebyrd


    Jun 12, 2000
    Thanks for the info Chucko. I found that M.Friend sells a cable that'll go from banana to 1/4", or speakon to 1/4". I'll probably a couple of both. Thanks again!
  4. Petebass


    Dec 22, 2002
    QLD Australia
    hmmm.... that's not entirely true. Traditionally guys with small amps have to push em so hard to be heard, that end up sending a clipped signal to the speaker cab.

    In this case the 200w amp under clip would put out 400-450watts, so your 600w speaker should still be OK. But it's something you should be aware of.
  5. I have a question about this too. I want to get a QSC RMX 850. But i'm curious, to run in bridged mono, i need either a banana/xlr (in channel 1) to go to the speaker. The do i daisy-chain the speakers so they're both hooked up to the channel?

    Also, there are two "red" channels for br. mono. those are speakon, right? how would i use that? im just wondering, because i read the manual online and nothing really "clicked"
  6. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    With bananas its probably red-red for bridging. If you're using the speakons, you plug into Channel 1's output but the connector must be specially wired to place the load across pins 1+ and 2+ (not 1+ and 1- as would be done for normal stereo/dual mono operation).
  7. so would i daisy chain the cabs into the channel 1's output?
  8. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    There are two ways that you could do it. Method 1 would be to run a cable from the speaker output to cabinet number 1 and then another cable from cabinet number 1's other jack to cabinet number 2.

    The other way would be to run a cable from the banana jack to cabinet number one and then plug the second banana plug into the first one (and then into cabinet number 2).
  9. yeah, so from the channel 1 output, i would daisy chain the cabs.


    right? but would that give me the briged mono effect?
  10. PolkaHero

    PolkaHero Supporting Member

    Jan 5, 2002
    Is there any advantages/disadvantes to either method? For instance, is there some power loss to the second cabinet when daisy-chaining both cabinets together?
  11. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    To use the bridged mono mode you have to set the little dip switches on the back of the amp to the bridge mono mode.

    Personally, I'd go with daisy chaining. You'd only lose power to the second cabinet if you were running really high power levels and you had whimpy little speaker cables. I use 12 AWG with banana and Speakons and 14 AWG when I'm using cables with 1/4 in. plugs.