Question about SWR Working Pro Rig?

Discussion in 'Amps and Cabs [BG]' started by Bowedtoothdoc54, Nov 3, 2016.


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  1. The Regulator

    The Regulator

    Aug 10, 2005
    The WP 400 & 700 are both 4 ohms.

    400W @ 4 ohms; 250W @ 8 ohms

    700W @ 4 ohms; 450W @ 8 ohms
     
  2. alexgeddy

    alexgeddy Supporting Member

    Feb 25, 2007
    NJ
    Hi If you use an ohmmeter to measure the speaker you are not measuring the impedance but the DC resistance, even though the cab says ohms. For an 8 ohm cabinet you should measure about 5.6 ohms DC. I forget the exact number for a 4 ohm but I think it's around 2.3 or something like that. When you measure these numbers don't panic and think something is wrong cause it's not. Impedance and Ohms are 2 different things. Ohms is much more straight forward. Impedance is more complicated to explain. hope this helps....
     
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  3. alexgeddy

    alexgeddy Supporting Member

    Feb 25, 2007
    NJ
    .
     
  4. In that light, I'd try the series speaker cable for sure.
     
  5. That's what I was wondering. I owned a SWR 750x for about a decade. It could run 2.6 just fine. Not sure about the head the op mentioned though.
     
  6. Bowedtoothdoc54

    Bowedtoothdoc54

    Nov 3, 2016
    Thanks Everyone for the input! Based on all the posts I am thinking that I would probably give out before the rig :).
     
  7. Andyman001

    Andyman001 moderation must be taken with a grain of salt

    Feb 11, 2010
    S/E Idaho
    Looks like you used the "diode check" setting, The meter needs to be on Ohm setting - Omega symbol.
     
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  8. Bowedtoothdoc54

    Bowedtoothdoc54

    Nov 3, 2016
    Ok, Thanks! I am thinking the Ohm setting would look kind of like a horse shoe?
    Will try again after work today and report back.
     
  9. Andyman001

    Andyman001 moderation must be taken with a grain of salt

    Feb 11, 2010
    S/E Idaho
    Yeah, kinda looks like a horse shoe.
     
  10. john m

    john m Supporting Member

    Jan 15, 2006
    What meter do you use to measure z? What frequency do you set your meter at? Z varies with frequency, DCR does not.
     
  11. Bowedtoothdoc54

    Bowedtoothdoc54

    Nov 3, 2016
    I have a cheap Craftsman unit from Sears. I was just looking at the manual and It looks like I need to move one of the wires to a different terminal for measuring Ohms?
     
  12. Andyman001

    Andyman001 moderation must be taken with a grain of salt

    Feb 11, 2010
    S/E Idaho
    what model meter is it?
     
  13. Bowedtoothdoc54

    Bowedtoothdoc54

    Nov 3, 2016
    It's the 82141
    Craftsman Multimeter | Part Number 82141 | Sears PartsDirect
    So here are my results with Vdc set to 200 and both cables to the right connectors.
    My Ampeg portaflex 115 which is an 8 Ohm cabinet tested 007.
    Both SWR cabinets tested 003. The 410 is supposed to be 4 Ohms and the 115 8 Ohms?
    I'm still not sure if I am doing the measurements correctly and the numbers are jumping all over the place before they finally settle down to the numbers above?
     
  14. BasturdBlaster

    BasturdBlaster

    Feb 19, 2012
    Crandon WI
    It would almost seem theyre both 4ohm cabs. I typically set the meter to the lowest attenuation, Im thinking your .003 reading is actually 3. I wonder if the 15 was replaced with a 4 ohm driver, hhmmm.....
     
  15. Did someone say 'serial speaker cable, easy fix'?
     
  16. Bowedtoothdoc54

    Bowedtoothdoc54

    Nov 3, 2016
    So I would go from amp to 4 Ohm cabinet and from 4 Ohm cabinet to 8 Ohm cabinet?
     
  17. Yup... easy and done
     
  18. Just to be clear... a serial speaker cable is a special thing, though.
     
  19. Primary

    Primary TB Assistant

    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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