Poweramps: Bridge/Stereo and why?

Discussion in 'Amps and Cabs [BG]' started by kennyhoe, Aug 7, 2003.

  1. If you have two cabs and a poweramp, is it better to bridge them, or run them both in stereo? Take the Carvin DCM1000 for example, either 500w at 2 ohms per channel (both cabs 4 ohms), or 1000w at 4 ohms bridged (both cabs 8 ohms). Which option would be better, and why? What is the difference between running in stereo, and daisy chaining?
  2. I'm wondering why your amp has a 2ohm rating per channel and a 4ohm rating for bridged mono. If the amp is stable at 2ohms it should be able to carry that load in bridged mono mode as well. You might want to see if this is the case. In any case, to answer your above posted question-

    If you're using a stereo power amplifier in stereo to power two 4ohm cabinets, the amp sees a 4ohm load. You see, each side of the amp is it's own seperate, independent amplifier. If you plug a 4ohm cab into each of it's sides, each side "sees" a 4ohm load.

    Only through "daisy chaining" two 4ohm cabs together would you get a 2ohm load. In your above scenario, you would need to run two 4ohm cabs (daisy chained) off each side of the amp for it to make that 500 watts per channel @ 2ohms.

    Your best bet would be to get two 8ohm cabinets, daisy chain them together, and run your amp in bridged mono mode. That is, of course, unless you want to run FOUR 4ohm cabs!!! That would be the only way to get the 2ohm load per channel. I'm guessing that by that point though your amp wouldn't have enough power.
  3. Run the 1000 at 4 ohms. It will be easier on the amp.
  4. thx for all the replies

    ok, so i should get two 8 ohm cabs, and run it mono-bridged, resulting in 1000w from the poweramp. how would the cables go, as i am planning to get avatar speakers.

    poweramp --speakon-->2x10---1/4"-->2x12

    how many watts would each cab get and would there be a problem with sending that many through the 1/4"?
  5. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    The minimum rated impedance in bridged mode is ALWAYS twice the minimum rated impedance per channel in stereo or parallel mono mode. This is because in bridged mode each side of the power amp is only seeing half the impedance of the load that they are sharing. Nowadays most power amps will drive down to 2 ohms/channel and hence do 4 ohms bridged but there are still some out there that don't (which includes Stewart World amps) - worth making sure of that if you're looking to bridge.

  6. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio!

    Jul 3, 2001
    Chester, Connecticut
    Former Technical Communications Developer, QSC Audio
    If you want individual control of the cabinets, then run the system in stereo (or parallel mono). For more power or headroom, run the amp in bridged mono with the speaker cabinets themselves connected in parallel. You do run a greater risk of damaging your speakers if you're not careful, though.

    The difference between running in stereo and daisy-chaining is like the difference between walking to work and bringing your lunch. IOW, they're two different things that aren't dependent on each other. Stereo is just operating your amp's two channels independently. Daisy-chaining is just a way of parallel-connecting inputs (of amplifiers or speaker cabinets) by connecting a cable from one to the next, and maybe on to the next, and so on.
  7. Thanx again. So to clarify this up, in order to get the full 1000w, I would either have to mono-bridge 2 8-ohm cabs, or make it so that I have 2 ohms PER CHANNEL (four 4 ohm cabs altogether), resulting in 500w per side?
  8. boogiebass


    Aug 16, 2000
    :D Good one! But what's the difference between taking the bus and sleeping thru the staff meeting?
  9. On my Carvin DCM2000, to run bridged you cannot use a 1/4 cable, you have to get a Speak-On/1'4 adapter if your buying Avatar cabs, then daisy chain it with a 1/4.
  10. doc540


    Jul 28, 2003
    Beaumont, Texas
    "The difference between running in stereo and daisy-chaining is like the difference between walking to work and bringing your lunch."

    Now that's the kind of technical explanation a guy like me can understand.