Combo line out into a powered speaker cabinet? Some guidance please.

Discussion in 'Amps and Cabs [BG]' started by CocoaThumper, Aug 18, 2017.

  1. CocoaThumper


    Aug 18, 2017
    Hey there.

    I don't know the most about amplifiers as I've always used combo amps for simplicity. I'm still researching amp heads and speaker cabs before I make the jump away from combos.

    In the mean time I was curious about powered cabs. I know a combo cannot power a passive cab without a Speaker Out...which my combo doesn't have.

    I have a line out though. Would lining out into a powered cab though give me a weak sound ?

    Would using the line out from my 2x7" 100w combo into a 1x12" 300w powered cab work well? Would I get full use of the powered cab? And lastly, would I have to worry about ohms or anything else?

    Thanks for your help.
  2. lz4005


    Oct 22, 2013
    Ohms in the most common power amp/speaker cab rating sense wouldn't be an issue.

    As for the line depends.

    Each powered cab will be designed to see a certain level of signal. And line outs can vary in their level of output.

    There's a good chance it will work ok.

    But if at all possible, try them together before you buy.
    David Jayne and BadExample like this.
  3. BadExample


    Jan 21, 2016
    The other question might be will the combo and powered speaker sound good together. As Kim Jong Il always said, "Try before you buy."
  4. Stumbo

    Stumbo Guest

    Feb 11, 2008
    Which amps are in question?
  5. CocoaThumper


    Aug 18, 2017
    The combo is a Phil Jones Session 77. The powered cabs I'm considering are the Phil Jones Sub One and possibly a Gallien Krueger. Think that one was 200 w
  6. lug

    lug Supporting Member

    Feb 11, 2005
    League City, Tx
    I run a Phil Jones Double 4's line out into an Presonus Eris 8. Works perfectly. A line out level is all a powered speaker needs.
    CocoaThumper likes this.
  7. basscooker

    basscooker Commercial User

    Apr 11, 2010
    Northern KY
    Cab fan, hobbyist
    The gk is designed to work specifically with other gk products and probably won't work for this. I think I read (here) that the mbe's require a really hot signal that most line output levels fall short of. Yes try it first, I suggest calling gk also.
    packhowitzer and pglaser01 like this.
  8. lz4005


    Oct 22, 2013
    The wiring for plugging into a gk is their own odd setup as well. Would require a custom adapter to work. In addition to the potential level issues.
    CocoaThumper likes this.
  9. I understand that you're going for simplicity so I'll try to stay in topic. Obviously the phil jones will work perfectly with the phil jones you already have. They even display it as an example on their site. If you're thinking of going to another brand for cost sake, then Jong's "try before you buy" is a very good idea. Ohms won't matter, but the actual power output of the line out is unknown. That's why most preamps are adjustable. The powered cabs you're looking into don't have that option. If you try other brands, don't be timid. The line out output should be tied to the 77's master volume. That way you don't have to fight with two volume knobs. Crank your 77 way up and make sure it still sounds the way you want it to. And... Good luck!
    obimark and CocoaThumper like this.
  10. CocoaThumper


    Aug 18, 2017
    I almost bought that model. I originally went in the store set on a Warwick combo....but saw the Phil Jons double four and was blown away at the sound, small size and weight.

    I ultimately chose the PJ Session 77 but really was impressed with all the Phil Jones stuff in the store.
  11. CocoaThumper


    Aug 18, 2017
    Thanks for the heads up
  12. GK powered extension cab needs a separate power cord and is connected to the combo with a XLR cable. It works very well with GK combos. :D
  13. Tim Skaggs

    Tim Skaggs

    Sep 28, 2002
    Works very well with SOME GK combos. My GK MB150e will NOT work with GK powered speakers according to GK themselves. It's too old, although GK still makes the same amp that will work with GK powered speakers. A marketing thing for sure, but one which has me looking at other products...
  14. Welcome to TB.

    GK line out is BALANCED audio running about +10 dbu signal level.
    This is about 6db hotter (twice as hot) as most balanced XLR line level equipment.
    You may not be able to fully drive a GK powered cab from a non GK line out.
    In most cases, it will probably be OK. You just won't get everything out of it like you would with a GK to GK connection.

    The issues with feeding a powered cab between different manufacturers will not only involve problems from differing levels, but also the interfacing of balanced and unbalanced audio. Balanced audio uses two conductors, not including the cable shield. Unbalanced uses one conductor AND the shield. The connectors you normally see are XLR for balanced and 1/4" Tip/Sleeve for unbalanced. There are adapters that convert between XLR and 1/4", but there is more to a proper interface than just the adapters. Not doing a proper adaptation between balanced and unbalanced can lead to problems such as loss of signal level or hum for instance.

    Then with XLR outs on an amp (GK excluded) there are line level, normally about +4 dbu and mic level, which will be somewhere around -50 dbu. These are normally the amp's DI output and are meant to feed a mixer line or mic input.

    This all makes the "try it before you buy it" crucial to having your plan be successful, unless you are well versed at interfacing audio that is not normally meant to work together.
  15. CocoaThumper


    Aug 18, 2017
    Thanks for all the replies. Still learning hear. Ill make sure to do testing out of cabs before I buy anything. Very helpful replies
    Old Garage-Bander likes this.