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amp/speaker hook up

Discussion in 'Amps and Cabs [BG]' started by bizzaro, Mar 4, 2001.


  1. bizzaro

    bizzaro

    Aug 21, 2000
    Vermont
    I want to hook up a 4 Ohm speaker to an 8 ohm amp jack. Can I do this without threat of damage to amp or speaker??
    Here's the skinny. I've got an amp with two speaker jacks that are labeled 8 Ohms. I have two speakers that are labeled 4 Ohms. I want to hook them up. Will this work or will I risk damage to either??
     
  2. Oysterman

    Oysterman

    Mar 30, 2000
    Sweden
    You will fry your amp.
    I think.
     
  3. bizzaro

    bizzaro

    Aug 21, 2000
    Vermont
    Bummer. Could someone confirm oystermans post??
    Thanks - bizzaro
     
  4. Anytime you hook up a higher impedence speaker to a lower impedence jack i.e. 8 ohms speaker to 4 ohm jack, or 4ohms cab to 2ohm jack you are going to smell smoke very soon
     
  5. Oysterman

    Oysterman

    Mar 30, 2000
    Sweden
    No, PhatBoi, it has got to be the other way around. Lower impedance on the speakers than what's minimum for the jack will fry the amp. 4 ohm cab in a 2 ohm jack is A-OK, but the other way around is a no-no.
     
  6. I know that it was a Duh!! I was a first put "higher imp. of speakers good, lower bad" but I didn't think that'd make sense, so I ended up blabbling and confusing myself. I know better than that
     
  7. bizzaro

    bizzaro

    Aug 21, 2000
    Vermont
    Thanks guys. This is all really foreign to me. I don't know sqaut about electronics. But it sort of makes sense to me I guess. Got to study up on this stuff. Any recomendations on a basic book on the subject?
     
  8. Oysterman

    Oysterman

    Mar 30, 2000
    Sweden
    Everything I know about the subject (which isn't much, BTW) is to be read in the Amps forum. Seek and thou shalt find. :)
     
  9. JMX

    JMX Vorsprung durch Technik

    Sep 4, 2000
    Cologne, Germany
    Connect those two 4 Ohm speakers in serial

    4 + 4 = 8 Ohm

    and connect that to the 8 Ohm output.
     
  10. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    Keep in mind that when JMX says connect them in serial that does not mean just connect both to the amp. Nor does it mean daisy chain them to the amp. most cabs are wired in parallel, so you have to make or buy a special cable that will connect your speakers in series.
     
  11. bizzaro

    bizzaro

    Aug 21, 2000
    Vermont
    The cab I want to hook up has 4 speakers in it and its wired with three on one hook up and one on the other. Not knowing the difference between series and parrallel I had better leave it alone. I should have a replacement speaker roll in today that will solve my problem.

    Thanks Again,
    bizzaro

    ps-Book recomendations anyone??
     
  12. Sorry bizzaro, no book recommendations but if you do some searching in the Amps forum you should find some mega threads on impedance, sensitivity, power, SPL etc etc.

    Oysterman's advice in his last post is correct. ;)

    Happy hunting :)
     
  13. If the amp is solid-state (transistor), then your total speaker impedance has to be equal to or above the minimum. The amp will only put out max rated power when the speaker impedance is equal to the minimum that the amp is rated for. Most likely, nothing will fry with a higher impedance hooked up to the amp. It's supposedly even OK to run the amps with no speakers hooked up (infinite impedance). I've done it with no problems before, but I can't guarantee it'll be safe on every amp.

    If the amp is tube, mismatches are bad in either direction. If it's too high an impedance, the tubes and transformer get beat-up to the point of death by high voltage spikes. If the impedance is too low, too much current flows and can fry your tubes or transformer. But tubes can deliver full rated power to different loads that they are designed for, not just the minimum. My old Ampeg V4B can put out 100 Watts into 2, 4, or 8 ohms, switch selectable at the output.

    Chris