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need help with ohmns problem

Discussion in 'Amps and Cabs [BG]' started by kuntacore, Apr 8, 2001.

  1. kuntacore


    Feb 26, 2001
    I am currently running a 210 tvx and a 115 bxbw out of my peavey firebass 2. the minimum impedence for my peavey firebass is 2 ohms. my cabnets are each rated at 4 ohms, so together they make 2 when i run them both into my amp head. my problemo is that my amp sometimes overheats and certain settings, so i decided to check my cabs with a volt meter, according to my volt meter my 115 bxbw was at 3.4 ohms, and my 210 tvx was at like 3.1 ohms. i was wondering if this is a big enough change from what they are supposed to be (4) to make my amp overheat.

    also i was wondering if i could somehow correct the cabnets so they rate correctly at 4 ohms by mabey taking it in or doing something to it to add more resistance. thanx.
  2. RockFiend


    Aug 23, 2000
    i was once checking the impedance on a 2x15 Sunn cab so that i could test it out with my ampeg head, the head was rated as going as low as 4ohms, so i strapped a 2x10 and the 2x15 to it,,,, when checking the impedance on the 2x15 to see if it was at 8ohms I got a reading of around 6.3-6.6 i can't remember,, i had a talk with a tech at my local store and he said that that was perfectly normal and the cab was still an 8ohm'er,,,, so i hooked up the two 8ohm cabs to the head, dropped er to 4ohm split and it was fine....
    working with the 2ohm situation i can't say i know too much,, but all i'm saying is, is that i had a reading far less than 8 but it was still considered an 8 ohm cab, and the split worked just fine... hopefully this helps in some small way
  3. The load of an unused speaker cabinet is always going to be slightly lower than it is when it's actually in use. I'm not sure exactly why this is but it is normal and I'm sure one of the tech heads here will get into it farther.
  4. The impedance rating is specified at 1 kHz. When you measure it with a voltmeter you get the 0 Hz (DC) value, i.e. the resistance, which is always lower than the 1 kHz impedance.

    To make things more complicated, the impedance varies widely from 30 Hz to 20,000 Hz, maybe from 8 to 50 ohms. But that's of no concern to you. The amp should be able to handle those changes.


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