head+cab set up - another impedance/power related question

Discussion in 'Amps and Cabs [BG]' started by luisnovelo, Feb 11, 2003.

  1. Ok.. I have a very poor knowledge on anything related to building up a rig but have been looking for a nice but cheap amp. The stuff that seems to get closer to what I expect are the next:

    I'm thinking of buying a Hartke 4000 Head which produces 400 watts at 4 ohms and 220 at 8 ohms..
    AND.. a 4 x 10 cabinet (Hartke VX 410) which handles 400 watts at 8 ohms..

    So my question is..

    Does that head make that cab deliver as much power as it is meant to?

    If it doesn't, is that a disadvantage? should I get a different set up?? (Eg: more powerful head or two 2x10" cabs)

    Alsoi what would happen if I add another cab to the set up... Would the cabs work better?

    Any info and recommendations are welcomed by this ignorant human being..[​IMG]
  2. Brooks


    Apr 4, 2000
    Middle East
    If you go with 4x10 cab at 8 ohms, you will be getting only half of the power (220W). So, you could either get two cabs of 2x10 at 8 ohms each, which will mean combined 4ohms, thus delivering the maximum power, or you could get a 4x10 cab that is 4 ohms.

    Finally, you could also get a 4x10 at 8ohms plus another cab at 8ohms. Personally, that would be my choice. Whichever you chose, I would suggest two 8ohm cabs or one 4ohm cab so that you can get all the power out.
  3. Petebass


    Dec 22, 2002
    QLD Australia
    That's right. Your amp will be pushing against 8 ohms of resistance and produce 220W. If you reduce the resistance to 4 Ohms, the amp delivers the full 400w. In theory that's sound slike a lot but in practice it's not actually much louder. The bulk of the volume jump comes from adding the extra speakers more so than adding the extra watts. Either way, 2 cabs are louder.

    Oh and whatever you do, don't ever go below 4 ohms on that amp. It will overheat the amp and more than likely blow it.
  4. Thanks Guys..

    I know is not the big deal but you really helped me undertanding this issue..

    i just have another doubt..

    I guess that if I plug two 8 omhs cabs to this same amp, the 400 watts are going to be divided into the cabs so that each gets 200 watts of power.. Is that right???
  5. Brooks


    Apr 4, 2000
    Middle East
    Well...assuming that both cabs are exactly the same, yes, you a right. In practice, this is rarely the case, but don't worry too much about it.
  6. Hmmm, odd.

    Why wouldn't the power be distributed evenly? Both cabs have the same impedance, right? That means both cabs get the same amount of power.

    Care to elaborate?
  7. Brooks


    Apr 4, 2000
    Middle East
    Yeah, you are right. I was looking at it from the other side - power as we perceive it. SPL rating would probably not be the same unless cabs are identical, so one cab is likely to sound louder. But yeah, you are right - given the same impedance, they would both receive 200W each. Sorry for the misleading info.