Gibson Thor speaker/swap question.

Discussion in 'Amps and Cabs [BG]' started by MasonMinor, Mar 6, 2017.

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  1. MasonMinor

    MasonMinor

    Nov 29, 2014
    Kentucky
    I have an 8 ohm 12" out of a Peavey PA, and I removed the 10's from the Thor, but they have no indication whatsoever on them as to the ohms or power handling. I intend to put the 12" in it, but I don't understand all this stuff about impedance yet. Can someone offer any word as to the impedance of the stock speakers?
     
  2. MasonMinor

    MasonMinor

    Nov 29, 2014
    Kentucky
    Bump. Anybody?
     
  3. Gaolee

    Gaolee Official leathers tester and crash dummy

    Have you checked them with a multi-meter? Other than that, I don't know anything about them. Maybe nobody else does either.
     
  4. MasonMinor

    MasonMinor

    Nov 29, 2014
    Kentucky
    I don't have a multimeter on hand, but I figured as common as these used to be, someone would know something about them. I guess not. Oh well. I guess I'm gonna hook this 12 up and see how she sounds.
     
  5. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
  6. yodedude2

    yodedude2 Supporting Member

    Nov 19, 2005
    san antonio, texas
    agreed. is the op's amp tube or solid state? unknown/random speaker install sounds like a good way to wreck the amp.
     
  7. bobcruz

    bobcruz

    Mar 10, 2004
    CA
    Good info on JohnK's website. The speakers are 8 ohms, but the schematic is pretty minimal regarding how the speakers are wired, so OP, if they're wired in series (and you absolutely need to understand what this means), then the amp's output transformer is set up for a 16 ohm load. From what I've learned here on TB, it will not "wreck" your transformer to run a load that is LOWER than the transformer is set up for but you won't get full power and you will possibly affect the tone. If the speakers are wired in parallel, then the amp's output transformer is set up for a 4 ohm load and an 8 ohm speaker will present greater resistance, possibly causing heat and longevity issues along with less than full power and possible effects on tone. You need to research these concepts, understand them better than I do, and proceed with caution. Peace, Bob
     
  8. MasonMinor

    MasonMinor

    Nov 29, 2014
    Kentucky
    Solid state. I disconnected the 10's and plugged the 12 in, even sitting across the room, it sounds okay. Not like It's about to explode. But I didn't have the volume up very far.
     
  9. MasonMinor

    MasonMinor

    Nov 29, 2014
    Kentucky
    Yes, I understand the series and parallel part, just the whole ohm thing was blowing my mind. I understand it somewhat better now. So you're saying if I had another one of these 12's, and I wired them in series, then hooked them up to the amp, it would be running fine, yes? The speakers were wired in series when I got a hold of them. Or if I had say a 15 that was 16 ohms, that would work too, right?
     
  10. yodedude2

    yodedude2 Supporting Member

    Nov 19, 2005
    san antonio, texas
    in general, yes. solid state amps are more forgiving into higher than rated resistances (the opposite of tube amps). when driving loads into lower than rated resistances (as you are now doing), solid state amps begin to burn up as gain is increased.

    again, this is all a gross generalization on my part. good luck.
     
  11. MasonMinor

    MasonMinor

    Nov 29, 2014
    Kentucky
    Thank you for the good luck and this new knowledge! I will see how it goes, and if I can find another 12"...
     
  12. bobcruz

    bobcruz

    Mar 10, 2004
    CA
    Oops, dang, I read JohnK's site and figured these amps were all tube amps but I guess there are some SS Thor amps too. So forget anything I said about transformers--tubes and SS are opposite in this respect. With SS amps, you don't want to go BELOW the amp's rated ohms, while with tube amps you generally don't want to go ABOVE the rated ohms but going below won't wreck the amp--it just won't produce as much power and sound like it should. So if your amp is SS, and it used two 8 ohm speakers in series, that's a 16 ohm load and you don't want to go BELOW that (unless the amp designer says it's OK). So don't crank that 8 ohm 12 you have in there now until you get another one to put in series for a 16 ohm load. And a single 16 ohm speaker would be fine also. Peace, Bob
     
  13. MasonMinor

    MasonMinor

    Nov 29, 2014
    Kentucky
    Thank you so much!