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QSC power amp questions...please help?!

Discussion in 'Amps and Cabs [BG]' started by Ahhhson, Jun 10, 2003.

  1. Ahhhson

    Ahhhson Guest

    Jun 5, 2003
    ALBANY NY 518
    Im pretty convinced on the QSC 1850HD for my bass setup (including a stingray 4, a Sansamp RBI as a preamp, and the Ampeg 8x10)

    Can someone tell me how the power amp works?
    THe cab is 4 ohm and the power amp is advertised at having 600w @ 4 ohms, which is plenty for me, but theres two channels? does that mean it gets cut in half to 300 and 30o per channel? Do you use only one channel? Wheres the input and how do they set up ( with such preamps as the RBI)?
    If someone could briefly give me the jist of this product that would be great...

    Lastly can someone briefly explain bridging and the massive amount of power that is advertised with it,
    THank YOu.

    Also see me gear posts below to help me out...
  2. chucko58


    Jan 17, 2002
    Silicon Valley, CA, USA
    I paid for all my gear myself. Well, me and MasterCard.
    I have one of these. They're beefy, durable power amps - heck, you could practically weld with one! - but they're heavy, and the cooling fan is a little noisy. Do yourself a favor and get the rear rack brackets.

    Each channel can put out 600 W into 4 ohms. The inputs are on the back; you can either use a standard 1/4" phone plug, balanced (TRS) 1/4", or balanced XLR. From what I've heard, the Sansamp RBI should drive it just fine.

    In bridged mode, one channel is driven normally, the other driven with an inverted signal. You take the output across both channels. This effectively doubles the output voltage (6 dB gain increase), but each amp sees half the load impedance. In the case of the RMX 1850HD, this results in 1800 W into a 4 ohm load!

    Yes, it will do this all day, with no mirrors and no smoke (as long as you don't hook up a load of less than 4 ohms, that is).

    You could drive your Ampeg cab from one channel of the RMX; or if you're brave, you could drive it bridged. I doubt any wimpy g**t*r player would be able to step on your sound with that rig. Move over, Mr. Marshall Stack!! :D :D :D
  3. Ahhhson

    Ahhhson Guest

    Jun 5, 2003
    ALBANY NY 518
  4. Petebass


    Dec 22, 2002
    QLD Australia
    Think of it as two seperate 600w amps joined together. Bridging is like running both so you get one thumping huge 1200w amp.
  5. The 1850HD is specifically designed to run with 2-ohm loads. The only downside is the 45 pounds.
  6. somewhere in the past, on one of these amp threads, there was a suggestion as to the best place to buy QSC amp. Can anyone help? I too am 98% sure I'm gonna get a QSC, but obviously I want to save as much $$$ as possible.
  7. SharkB8


    May 29, 2002
    Lord Valve seems to have the best price I've found yet, he's very helpful and answers any questions. I'm getting ready to pull the trigger on a PLX as well....

    His web site is:


    Good luck

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