Wiring Cabs, Speaker OHMS all in one thread

Discussion in 'The Squawk Box' started by JakeM, Feb 19, 2011.

  1. GitFiddle

    GitFiddle Premium Member

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    Most amps I have seen with multiple speaker outs usually have them wired parallel. It sounds to me like you are providing a 2 Ohm load to the amp instead of 4 but someone else may know more details about that specific amp.

    A while back I had a similar situation with a couple stereo 2x12 cabs. Each speaker was 4 ohm with a separate jack for each. Instead of rewiring the cabs I picked up a little project box and six 1/4" jacks from Radio Shack. I made two sets of two jacks wired to a third in series. This allowed me to wire each stereo cab at 4 ohms (each speaker) as a mono cab at 8 ohms without changing anything in the cab.

    Since the cabs had that kind of furry fabric on them, I just slapped a piece of velcro "hooks" on the bottom of the box and it just slaps onto the back of either cab.
     
  2. onioner

    onioner Senior Member

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    Quick stupid question: I can solder wire directly to the tabs of a speaker, right? One doesn't need the quick connector that I generally see, yah? For a 1x12, Positive to tip, negative to sleeve, and I'm done.

    Yes, I said they were stupid questions. Just sayin'. Kinda thing you wanna be sure about.
     
  3. JakeM

    JakeM Senior Member

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    Yes you can solder them straight on no problem
     
  4. GRIMESPACE

    GRIMESPACE Junior Member

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    Hiya - great thread

    I have a 4x12 cab running 16Ω speakers. It currently has 2 jacks - plugging into the 'mono' jack gives me a 4Ω (all speakers in parallel) load. Connecting to both splits the cab into two 8Ω pairs. I use the stereo config with my head, which has two 60-watt outputs.

    I've just bought a new tube head, which is wanting to see 16Ω. I'd like to rewire the cab using two jacks such that the mono input puts the speakers into series-parallel or parallel-series for the new amp, but I'll still have the ability to use my stereo head in the 2x8Ω config.

    I know that the 1960 Marshall cab has a similar config with 4x16Ω speakers, and there's a switch that changes from 4Ω to 16Ω on the mono port while still allowing a stereo config. That would be fine, but ideally I'd hardwire the whole thing to 16Ω rather than using a switch.

    Anyone have this diagram? I've seen some close ones out there, but nothing's hit me as 'that's it!!!!'.

    Any help would be seriously mucho appreciado, and yes - I'll be happy to post pics of my wiring scheme for the thread!

    Thanks!
     
  5. JakeM

    JakeM Senior Member

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  6. snaredrum

    snaredrum V.I.P. Member

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    ok guys - i want a more 70s crunchy tone from my yngwie yjm100 1959slp. i have a 2x12 cab with vintage 30s in currently.

    is there any safe way to get some greenbacks in there? if i only run the amp in 50w mode, would that be ok for two greenbacks?
     
  7. emptyisvarah

    emptyisvarah Senior Member

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    ok... has anyone figured out how to wire 2 16ohm speakers for a 16ohm total? thanks..
     
  8. PapaSquash

    PapaSquash Senior Member

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    can't be done.

    Either parallel for half - 8 ohms

    Or series for double - 32 Ohms
     
  9. emptyisvarah

    emptyisvarah Senior Member

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    just as i thought.. but its ok I guess as I seem to recall that a 2.1 step down is okay. thanks papa/ big J for the PM
     
  10. JakeM

    JakeM Senior Member

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    If it's a tube amp it's never really wise to step down, no matter what anyone EVER says. If you match your OHMS you never need to worry. It would be better to get it set right the first time and not worry. If you blow a tranny you're screwed and it will cost more in the long run if damaged. Don't tempt fate.\

    Jake
     
  11. emptyisvarah

    emptyisvarah Senior Member

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    thanks jake for the heads up! :)

    on a side note: spent the whole day yesterday (well maybe a couple of hours about 5-6 hrs) using the classic 20 thru my 8ohm 2x12 Kustom cabinet. everythings still working this morning thank god :)
     
  12. snaredrum

    snaredrum V.I.P. Member

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    so does series/parallel wiring only work if you have 4 speakers?
     
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  13. JakeM

    JakeM Senior Member

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    yes as the first pair are in series with eachother as a pair and then in parallel with the second pair
     
  14. emptyisvarah

    emptyisvarah Senior Member

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    i'll give a smile for this one :) good morning :)
     
  15. SludgeBurns

    SludgeBurns Senior Member

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    What is a "2.1 step down"?
     
  16. JakeM

    JakeM Senior Member

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    Sludge, I think he is talking about when using a solid state amp that it is safe to use an 8ohm cab with a 16ohm head. At least that's what I think...

    People often confuse this with tube amps and can lead to trouble. I can't justify some people's logic, "Ah sure it will be fine, won't it?". Why leave it to chance and complicate things when you can just as simply match amps and cabs properly.

    Jake
     
  17. randelli

    randelli Senior Member

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    I added a 16ohm 25W resistor to my 16ohm ladyluck speaker to get an 8ohm load. I only did this to test out my HELLFIRE build; and do not think it would be a safe application for the long term. I ordered a new 8ohm Reaper to complete the build so this was only used for about 20 minutes.

    In theory I do not see a problem with adding a resistor to acheive the desired load - although a speaker and resistor behave differently from each other - and this may cause an issue for your amp or speaker(s).

    So don't listen to me........ I don't know now why I even mentioned it :D
     
  18. JakeM

    JakeM Senior Member

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    Randelli, while you're here.. Any idea how to build a dummy load for an amplifier for silent recording? It's not something I want to do yet but maybe in the future.

    Jake
     
  19. randelli

    randelli Senior Member

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    I dont think I understand your term 'silent recording'.

    Do you mean having the amp fired up with a test signal to record measurements without driving all of the small rodents to the next township? I have heard of others using a large resistor, as mentioned up post, to do this. I have also heard of people using an old voice coil to do this as well.

    Do you mean make a silent audio recording? I usually put the power switch to 'super silent mode' :applause:
     
  20. JakeM

    JakeM Senior Member

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    Yes I meant Recording audio clips of the amp using a lineout but only letting the amp see the dummy load and not hook up a full cab to it. Crank the amp for the recording.

    Sorry If I wasnt clear it was that Damn Texas heat...

    Jake
     

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