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oh my Ohms are tired

Discussion in 'Amps [BG]' started by muddpuddle, Dec 22, 2013.

  1. muddpuddle

    muddpuddle

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    Mar 5, 2012
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    Can anybody help me understand amps and ohms

    I have an old peavy head that's rated 210 amps at 2 ohms. What would be the result of playing through a single 8 ohm speaker
  2. B-string

    B-string Supporting Member

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    Nov 21, 2008
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    I'm sure you meant 210 WATTS not amps. Being a SS amp, use of an 8 ohm speaker would just mean it will produce much less wattage from the amp.

    The "Stickies" are chocked full of ohms/wattage info.
  3. beans-on-toast

    beans-on-toast

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    Oh my is right! That would be 88,200 watts. I figure that you'd probably blow your speaker.

    First step in answering your question is to know what model amp you have.
  4. swamp_bass

    swamp_bass I love it when a groove comes together Supporting Member

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    The general rule is that an amp's output will be half at double the speaker impedance. Many amps aren't quite linear that way, but it's a good general way to approximate.

    So 210 Watts into 2 ohms becomes:
    * 105 Watts into 4 ohms,
    * 60 Watts into 8 ohms.

    Many amps deviate from that general rule. Often amps that are "stable to 2 ohms" use active current limiting at 2 ohms that limits power to approximately the same output as 4 ohms. If that's the case, then your output into 8 ohms would be more like 100 watts.

    So somewhere between 50 and 100 is the ballpark.
  5. nashvillebill

    nashvillebill

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    That series of Peavey power amps is rated:

    210 watts into 2 ohms at 1% THD
    140 watts into 4 ohms
    80 watts into 8 ohms

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