Discussion in 'Amps and Cabs [BG]' started by I.'.I.'.Nakoa, Jul 24, 2004.

  1. I.'.I.'.Nakoa

    I.'.I.'.Nakoa Guest

    Aug 10, 2000
    Fort Worth.
    If i run one 16 ohm can and one 8 ohm cab(each running form its own output from the amp), what is the total impedance? im assuming that as long as it is not below my amps lowest ohm rating, it cant hurt anything to run 2 different cabs... correct me if im wrong so i dont mess something up.
  2. BruceWane


    Oct 31, 2002
    Houston, TX
    5.333 ohms. Shouldn't be a problem with any amp that uses a solid state power section. Practically all SS amps are fine down to 4 ohms, many to 2.

    If you're using an all tube amp (SVT, Mesa 400+, Traynor YBA200, etc.) check the manual or contact the manufacturer first. Tube power sections deal with varying loads differently than solid state amps, and odd impedances can cause problems with some amps. You'll probably be able to do it, but I'm not sure if you should use the 4 ohm or 8 ohm output.

    BUT......the 8 ohm cab will recieve a lot more power than the 16 ohm cab, so it will be louder, unless the 16 ohm cab is more efficient.

    You can try it and see how it sounds, but this power imbalance is the main reason it's not all that good an idea to mix cabs of different impedances. It's not because it'll hurt anything, but because usually it's just not very useful.
  3. I.'.I.'.Nakoa

    I.'.I.'.Nakoa Guest

    Aug 10, 2000
    Fort Worth.
    Its a carvin tube amp(this is for my guitar set up.) it says 100 watts output at 4 8 or 16 ohms.

    thanksfor your input
  4. A9X


    Dec 27, 2003
    Sinny, Oztraya
    I'd try the 4 ohm tap first.
  5. notanaggie

    notanaggie Guest

    Sep 30, 2003
    "Impedance matching" is a bit over-emphasised.....

    A "4 ohm" speaker may be close to 4 ohms at about "A 440", but at an octave or two up from that, it may be 8 or 9 ohms, easily.

    At resonance, it may reach well over 20 ohms, more maybe if the cabinet is ported.

    So matching is really extremely approximate. In well-designed equipment, it isn't "instant death nerve poison" if you don't match exactly.

    Guitar folks may mismatch intentionally to change the sound.

    That said, I'd go for the closest match simply so as not to work the amp too hard (assuming it is a tube type with output transformer).

    A very few old amps are solid state with output transformers, and they tend to be much more fussy. You won't have one of those, so don't worry too much about exact, use the closest, which would be 4 ohms for the pair you mention.