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Amp head and speaker help needed

Discussion in 'Amps and Cabs [BG]' started by J3G2, Sep 24, 2010.

  1. J3G2


    Sep 24, 2010
    Hi guys, I have a problem 'cos I know nothing about amplification. I have been given a pair of identical 15 inch P.A speakers by a friend and each one can deal with 150 watts at 8 ohms, so I've been told. The brand is OHM if thats any use. I'm currently using a 30 watt combo amp to power these and the result is pretty poor to be honest. My question is, what kind of amp head would I need to get the full potential out of these speakers, and how would I need to hook them up(series or parallel)?
    Thanks for any help that you guys can offer.
  2. Engagechad


    Sep 3, 2010
    Richmond, VA
    I am no master either so I would suggest checking out the sticky on this topic

    Right now you are under powering your cabinets and that can be potentially very bad for the speakers. Before operating them any more at that wattage read up on ohms and stuff in that thread.

    You're probably going to need a head that pushes around 300 watts at 8 ohms

    As far as I know.
  3. BassmanPaul

    BassmanPaul Inactive

    OH NO!!!! Wait for it!
  4. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    At least there's that admission. :rollno:
    The honest truth is that no one can say unless you happen to come across an owner of the same speakers. I'm familiar with the Ohm brand, but they do hi-fi, not PA. Your best route is to take them to a music store and try some heads.
  5. Engagechad


    Sep 3, 2010
    Richmond, VA
    rut ro. Did I say a no no?

    I guess I'm the one who needs to read up speaker stuffs!
  6. MIJ-VI

    MIJ-VI Inactive Supporting Member

    Jan 12, 2009
  7. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    Can of underpowered worms aside, are these speakers already inside of some sort of enclosure? By the way the op was worded, it left some doubt. Anyway, as mentioned, best bet would be to go out and try some amps, see how they sound together.
  8. J3G2


    Sep 24, 2010
    Yeah the speakers are essentially cabs. Powering them is the only issue here. So would I need a 300w head at 8ohms, or a 300w head at 4ohms? I'm sure it's the latter after some more reading.
    I would go to a store and try out some heads, but I'm still not sure as to the amount of power that is needed. I might screw everything up, which is something that happens a lot to me:ninja:
  9. You could try wiring them separately in the same cab & then asking around for anyone that wants to put a dimed 100 watter thru them? It's easy and non-permanent.

    Only reason I say that is that one or the other - or both - could be either on the way out or not last long when hitched up to a bass head. I got hold of a couple of Fane 15" PA speakers a few years ago, my 200 watt valve head destroyed them in a few weeks. If you end up that way you'll be looking for a new cab soon after buying a new head.
  10. BFM is right. These are made to go with record players and similar hi-fi audio, not for really loud PA use.
  11. J3G2


    Sep 24, 2010
    Wow, I guess we learn something new everyday. Thanks for those tips guys. I found out by emailing OHM that the speakers are from 1983 and the guy said that it would be okay to use a 300watt bass amp at 4ohms. epic confusion but they were free, so I'll be looking for a new head soon. Thanks for everything guys!
  12. dincz


    Sep 25, 2010
    Czech Republic
    Worst case: disconnect them and they'll be underpowered by a factor of ...., well infinity I guess. That should finish them off real fast. :meh:
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