M6 Carbine 2 Ohm questions...

Discussion in 'Amps and Cabs [BG]' started by bb03, Apr 20, 2011.

  1. bb03


    Mar 1, 2009
    I have some questions for the Ohm experts. I have a Mesa M6 Carbine that allows for 2 ohm operation. It has a switch on the back to toggle between 8/4 ohms, and 2 ohms. At 8 ohms the amp puts out 300 watts; at 4 the output is 600 watts. When you "switch" to 2 ohms, the output stays at 600 watts, "due to a limiter circuit added to protect the amplifier" (from the Mesa manual).

    From my limited knowledge, it seems that if the wattage stays the same at both 4 and 2 ohms, than this amp would run cooler at 2 ohms than one that outputs higher wattage when going from 4 to 2 ohms (like almost all 2 ohm capable amps). Is this correct? Will it still produce more heat at 2 ohms, than 4, even with equal watts?

    If in fact, Mesa has done a good thing here, why don't more manufactures do this? I would think most people who want to run 2 ohms do so because they happen to have two 4 ohm(or a 4 and an 8) cabs...not because they're looking for more wattage.
  2. I would like to know the answer to this as well. I am always shopping for my next amp head, and all Mesa models will eventually end up in my hands.
    I would think that the amp would be running more current at the 2 ohm setting since the impedance is halved.
  3. ccouch7


    Feb 14, 2009
    Not really sure, I'm no Ohm expert, but I've ran my M6 (on the 2ohm setting) at 2.67ohms (one 8ohm cab and one 4ohm) pretty much and it didn't seem to run any hotter than it does at 4ohms (two 8 ohm cabs).
  4. bb03


    Mar 1, 2009
    Anyone got an idea on this...bfm, rpsands, greenboy? Someone? :help:
  5. rockstarbassist

    rockstarbassist Inactive

    Apr 30, 2002
    The Woodlands, TX
    Endorsing Artist: HCAF
    Why would they know- none of them play Mesa LOL

    it's been 2 days- why not just call them already if it's keeping you up at nights.
  6. rpsands


    Jul 6, 2007
    can't echo this advice enough. Always ask the vendor first. Folks here are sometimes equipped to call bs on vendors but I'd still ask the vendor firstt.

    For the record I played mesa for quite a while :) doesn't make a whit of difference as to my capability to answer technical questions about the amps though.
  7. bb03


    Mar 1, 2009
    rp, I'm hoping by "echo", you mean calling Mesa...not the whole of rockstar's sarcastic post.

    I did talk to someone at Mesa, and got a generic response to the effect of "the limiter keeps the wattage down, so the amp can run safely at 2 ohms". Which I already got from the manual. I was just looking for a more in-depth answer. I realize that Mesa made the amp, and should know more about it than anyone. What I was looking for was some outside ideas from the TB engineer types...isn't that what this forum is for? If you reread my questions, I think they are somewhat generic in nature... about the relationship between watts/ohms/heat.

    I will e-mail the techs at Mesa, as the CS dept. didn't give me what I was looking for.
  8. Vic

    Vic There's more music in the nuance than the notes. Gold Supporting Member

    Oct 14, 2002
    Central Illinois
    Staff, Bass Gear Magazine
    This is still hearsay, but at least it's what I heard from Mesa folks at NAMM, so maybe it's still post-worthy.

    The 2 ohm switch imposes a limiter on the power rails, which means it will keep the amp from trying to put out more power than it can safely source without overheating (I think a better way to put it than the manual appears to put it.)

    So the next question is, if it's just a safety catch, why not just leave it engaged all the time? The feedback I've gotten on this is, if you don't need it in the signal path, don't put it in. It won't hurt anything to leave the amp on the 2 ohm setting, but it might possibly impose some change to the dynamic behavior of the amp that could be regarded as negative. I haven't had this verified, but at least from a practical standpoint, it makes sense to me.

    Bottom line is, just use the switch as they say... only when needed.

  9. Primary

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    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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