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amp wattage question--2X70 versus 150

Discussion in 'Amps and Cabs [BG]' started by analogfreak, Feb 23, 2006.

  1. analogfreak


    Jan 30, 2006

    Newbie here. I couldn't find the answer to my question in the FAQ section, so apologies if this has been addressed before.

    I tend to do low volume jazz gigs and use a small combo amp when there's no drummer (GK Backline 110, etc.), and a Carvin PB 150 head with somewhat heavy 2X10 cabinet when a drummer's involved.

    My question: would two combo amps each having 70 watts and a 10" (the GK Backline 110) be about the same volume as a cabinet with 2X10 drawing 150 watts from a head (the Carvin stuff)? I realize that different 10" drivers have different characteristics, so let's assume for a moment all things (drivers) being equal.

    I like the GK Backline 110 and am considering adding a second one. I would run the line out of one unit into the "mix input" (post-e.q. power amp in) of the second unit. Would the two 70-watt combo amps produce something like a hypothetical 140 watt head going into a 2X10 cab?

    Michael Yoder
  2. Matthew Bryson

    Matthew Bryson Guest

    Jul 30, 2001

    Well, I think that sounds about right... BUT - I'm no expert, so maybe just consider this a "bump" and hopefully someone more knowledgeable will chime in.

    I'm just wondering if your GK combo can power an extension cab. I took a quick look at the GK site - but it wasn't clear as to whether the external speaker jack powers an extension cab as well as the internal speaker, or if the external speaker jack is only to be used when the internal speaker is disconnected. maybe somebody can shed some light on that for you as well.
  3. analogfreak


    Jan 30, 2006
    Thanks, Matthew.

    There is only one speaker output on the GK Backline 110, so, like you say, it's a choice between the internal speaker or a separate cabinet.

    I suspect that you are correct in tentatively answering my question in the affirmative. One thing I was able to try was to feed the line out of a Fender BXR 25 combo amp into the "mix input" of the GK, and the two together were so much louder that my neighbor called within two minutes to complain about "that loud music again."

    The cool thing about the GK is that the mix input is post e.q. but pre master volume, so one can dial in as much or as little volume as necessary to match the volumes of two combo amps.

    Any other opinions out there about whether there is a difference between two 70 watt amps each going into a 10", versus a 140 watt amp going into a cab with two 10's?

    Michael Yoder
  4. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Yes and yes. This is not an impractical way to increase your volume. I saw a guy do this with two GK MicroBass combo amps. You actually get a 6 dB increase in volume by doubling the power and the cone area at the same time.

    The other thing is you can put one amp under the drummer to help keep him on tempo ;)
  5. analogfreak


    Jan 30, 2006
    Thanks, fdeck.

    You know my drummer??


    I think the option of two 70-watt GK combo amps would give me both flexibility, portability, and economy (the Backline 110 goes for $225 shipped.)

    Thanks again.

    Michael Yoder