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OMG Ohms....

Discussion in 'Amps and Cabs [BG]' started by RickyWoo, Mar 6, 2018.


  1. RickyWoo

    RickyWoo

    May 26, 2016
    Okay... I'm trying to sort something out. Can someone tell me if my thoughts are right or wrong please?

    I'm just trying to wrap my head around ohms and what my limits are.

    What I know....

    1) You can run an SVT-CL @4 ohms into a 4 ohm cab.

    2) You can run an SVT-CL @4 ohms into 2 - 8 ohm cabs

    3) You can run an SVT-CL @ 2 ohms into 2 - 4 ohm cabs

    What I don't know....

    Can you run an SVT-CL @ 2 ohms into a 4 ohm cab and into 2 daisy chained 8 ohm cabs at the same time?
     
  2. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    central NY state
    Received a gift from Sire* (see sig)
    Sure - put the two 8 ohmers in parallel to get a 4 ohm load, then put that set in parallel with the 4ohm cab for a 2ohm load. Power distribution won't be even, but sure, it'll work.
     
    RickyWoo likes this.
  3. RickyWoo

    RickyWoo

    May 26, 2016
    Thanks. I'm not looking to do this by the way. I'm just trying to understand it better. So, much appreciated. I suppose this didn't really require it's own thread.
     
    bholder likes this.
  4. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    central NY state
    Received a gift from Sire* (see sig)
    You have to keep power handling (watts) capacity in mind too - in the case above, the 4 ohm cab will get 1/2 the load, and each 8 ohm cab will receive 1/4 of the load - so do the math on the amp's wattage and make sure it comes out within each cab's capacity and you should be ok. At least, that's the very basics of it, there's all sorts of possible complexities you can get into, I'm sure others will chime in if I didn't get it right...
     
    RickyWoo likes this.
  5. RickyWoo

    RickyWoo

    May 26, 2016
    Well at 300 watts tube, the 4ohm (rated for 500 watts) would receive 150 watts, and the two 8 ohm cabs (rated for 200 watts) would each receive 75 watts. So no worries there, if I understand your post. :)
     
    bholder likes this.
  6. JRA

    JRA my words = opinion Supporting Member

    yes, per bholder 's post.
     
    RickyWoo likes this.
  7. I think it may help to consider that solid state amps have rated minimum load they can operate into safely.
    The load being the total impedance of all connected speakers.
    The total impedance of the speakers (Ohms) is the load.
    The amp has a minimum impedance rating (Ohms).
    But the amp does not generate that impedance, it comes from the speakers.

    As long as you know the minimum impedance that the amp is rated to handle, and you don't go below that number with the total impedance of the connected speakers, you are good to go, impedance wise.

    The only impact is that if you have a higher speaker impedance load than the amp's minimum, such as an 8 Ohm load connected to an amp rated to operate at a 4 Ohm minimum, you may not and usually don't get all of the power the amp can provide. Think of the speaker load as drawing the power from the amp. The lower the impedance, the heavier the load, the more power it will draw from the amp. Up to a certain point of course.

    Tube amps are bit different in that matching the rated impedance will draw max power.
    Being above or below the rated impedance may see less power from the amp.
     

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