connecting a 100W head to 4x12 cab

Discussion in 'Amps and Cabs' started by GibsonMarshallguy41, Mar 3, 2015.

  1. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    I've been doing some research about OHMs, and I've been trying to get some input about this from different sources...

    I just want to make sure I'm connecting my amp head to my speaker cab properly. I have a Marshall DSL 100-H and an old Marshall 1960 (JCM900) 4x12 cab... on the back of the head, there are 3 speaker outs - two 8 OHM outs, and one 16 OHM out... for the past few months I've owned this amp, I've been connecting the 8 OHM out from the head, to the 4 OHM input of the cab, with the switch set to "mono"... is this correct?.. a friend of mine told me I should be going from 16 OHM (head) to 16 OHM (cab)... can someone please help me out?

    http://www.seymourduncan.com/forum/attachment.php?attachmentid=46758&d=1380578038&thumb=1
     
  2. GCDEF

    GCDEF Supporting Member

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    Why would you do that? Your friend is right.
     
  3. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    I don't know. unfortunately, I'm not very knowledgeable about OHMs. I tried looking stuff up online, but its all very confusing to me.
     
  4. GCDEF

    GCDEF Supporting Member

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    You want them to match. Set the cabinet to mono and run 16 to 16.
     
  5. The Whiz

    The Whiz Member

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    Maybe you should consider drums. There's no ohms there.
     
  6. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    ok. thanks, GCDEF.

    I'm wondering how this will affect my tone, compared to how I've had it connected for the past few months.
     
  7. GCDEF

    GCDEF Supporting Member

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    Should sound better, but the bigger concern is potential damage to the amp. You are using a speaker cable I hope.
     
  8. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    yes, of course.
     
  9. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    oh, you're hilarious. I forgot how many wonderful comedians there were on the TGP forum.
     
  10. The Whiz

    The Whiz Member

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    My most sincere apologies.
     
  11. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    its all good, man.

    I've been playing guitar for 27 years, but I'm always learning something new. I welcome all the knowledge I can get.
     
  12. The Funk

    The Funk Member

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    Yikes. Going from an 8 ohm output to a 4 ohm cabinet load is very dangerous for the amp. Makes it run entirely too hot. Like, it can catch on fire (this actually happened to an amp I had - before I had it). You can mismatch ohms the other way, like run an 8 ohm tap into a 16 ohm cab, but the best situation is to match the impedance.
     
  13. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    wow... I guess I've been lucky so far. nothing has sounded unusual over the past few months I've had it connected that way. but of course, I will be making sure I have everything set up properly from now on. thanks, everyone.
     
  14. GCDEF

    GCDEF Supporting Member

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    Most amps can take a mismatch, and with tube amps, if you have to mismatch, a lower impedance cabinet is usually the safer way to go. Still not a good plan long term.
     
  15. GibsonMarshallguy41

    GibsonMarshallguy41 Member

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    ok, gotcha.

    I'm looking forward to hear how the amp will sound with everything hooked up properly. unfortunately, I won't know until our next band practice, in about a week.
     

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