Discussion in 'Amps and Cabs [BG]' started by pbass1, May 21, 2005.

  1. pbass1


    Dec 8, 2004
    i was wondering....if i had a 120 watt combo amp with an di hooked that into a 2x10 cab....supporting 600 watts....would i only get to use the 120 watts of my combo?

    Also/or...if i hook up the combo to the 2x10, will i get 120 watts out of both the cobo and cab?

    any input is good

  2. Tash


    Feb 13, 2005
    Bel Air Maryland
    It depends on the combo. You will not get 120 watts to both cabs. Power amps are rated to a maximum amount of watts and that is all the put out. However adding an extension cab will benefit you in a couple ways. First amps generate a certian output at a specific number of Ohms, say 120 watts at 8 ohms. If you are power cabs of a HIGHER number of ohms the amp will out out less power.

    Most combos do not put out their full power into just the built in speaker, so adding an additional cab will usually make them put out more power. Make sure to check the rating of the amp in your combo to make sure the right impedence is used. If you got BELOW the rated impedence you can damage the amp.

    Secondly even if you aren't getting more power from the amp and extention cab will add more speaker area, which will move more air and create more sound. So you will likely sound louder/bigger/better with an extension cab even if you don't increase the power from the amp.
  3. Moving air efficiently is the can have a very inefficent speaker and 120 watt amp and what you will mostly have is a heater with some sound.
    Put an efficient speaker in (102-105 db) and you will have an impressive amp that sound more than 120 watts.
  4. Check to see what ohms the combo power is rated at.

    If its 120@4 ohms, you're probably only getting 70-75 watts into the built in speaker. In that case it only puts out 120W when you plug in another 8 ohm speaker. Then you get 60W into each, total 120W.

    Hopefully it puts out 120 into 1 speaker (8 ohms), and the extention speaker boosts that to around 200W total. But I doubt it. The number you saw (120W) and remembered is what they wanted you to remember, the 4 ohm output. The advertising goes something like: Massive 120W @ 4 ohms with optional extention speaker so you go away thinking you're pumping out 120W with just the combo amp, but are really only about 2/3 that power. Intentionally a little misleading, but not inaccurate.