Can I replace a 4 ohm stock speaker with an 8 ohm speaker in my 1x12 combo?

Discussion in 'Cabinets & Speakers' started by noise5150, Mar 30, 2011.

  1. noise5150

    noise5150 New Member

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    I want to replace the stock speaker in my MG100dfx 1x12 combo. The back the amp says 4 ohm (I wrote Marshall and they confirm 4 ohms) but I want to know if I can replace the stock MG speaker with a HM75 Warehouse Guitar Speaker and they only carry 8 and 16 ohm speakers. Can this be done considering the difference in the ohms? Oh and since Im on this topic, I also sometimes run that amp through my 8ohm 2x12 Avatar cab and it sounds great. I disconnect the internal speaker wire and then just use a good speaker cable to hook it up to the Avatar. Is this ok? because on the back of the combo it says "minimum total Imp. 4 ohm".
     
  2. chuckharmonjr

    chuckharmonjr Well-Known Member

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    Minimum is the key word in that phrase. With a solid state output section, the min number is the only one that counts. It would push 16 ohms as well. The only thing is you lose some of the rated power. Going from 4 to 8, your 100 watter would become roughly a 75 watter.
     
  3. noise5150

    noise5150 New Member

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    Ok so if I put an 8ohm speaker in there as a replacement that should be ok as well as running the combo through my 8 ohm 2x12?
     
  4. chuckharmonjr

    chuckharmonjr Well-Known Member

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    Actually if you put an 8 in the combo, and also run the 8 ohm cab, your load would be 4 ohms overall which is perfect. You'd be perfectly fine putting an 8 in there.
     
  5. Adwex

    Adwex New Member

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    Yes. What Chuck said.
     
  6. noise5150

    noise5150 New Member

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    Hey just to be clear, there is only one output on the back of the combo so I either have to use the internal speaker OR disconnect that and hook it up to the 2x12 Avatar so I just want to make sure thats ok. But it sounds like installing an 8ohm internal speaker is ok from what you guys are saying.
     
  7. Adwex

    Adwex New Member

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    Yes, it's ok. Solid state amps are a different animal than tube amps, it's ok to connect speakers of different impedance, the only thing that is affected is the power output. So like Chuck said, if you connect an 8 ohm speaker, the power output is reduced. A four ohm speaker will produce the maximum power the amp is capable of, any lower impedance will damage the amp...that's why solid state amps have a minimum safe speaker load, and are vulnerable to speaker cable shorts...if you short circuit the speaker wires, that equals ZERO impedance, and is a sure fire way to fry something.

    It's the opposite for a tube amp. Tube amps don't like higher impedances than they "expect", so if the amp sees an open speaker circuit, it can be damaged.
     
  8. Georgiatec

    Georgiatec Well-Known Member VIP Member

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    Can you use a 2 into 1 jack connector to run both?...or wire the internal speaker so it's always on and just use the input for the Avatar?. :)
     
  9. noise5150

    noise5150 New Member

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    I dont know but I probably would only run it one or the other because when I'm home if I use the MG, Ill plug it into the Avatar. The only time Ill use the MGs internal speaker is if I bring it somewhere to jam.
     
  10. chuckharmonjr

    chuckharmonjr Well-Known Member

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    Yes you could do that Georgia. Add a 1/4 inch jack and wire it in parallel with the existing jack. I believe the 100 watt head version of the MG series has just that arrangement.
     

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