How to add output jack to amp

Discussion in 'Amp Tech Center' started by 440mhz, May 6, 2021.

  1. 440mhz

    440mhz Tele-Meister

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    I hade no output jack on my amp. So I connected a guitar 1/4 input jack with speaker grade wiring to 2 spare +- connectors on the speaker. It works fine, but I'm not much on electricty and I'm wondering if it 's ok. Both speakers are 8 Ohm. Is there anything wrong with this. Thanks.
     
  2. dan40

    dan40 Friend of Leo's

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    It sounds like you have it wired in parallel which is fine. You may want to post a clear pic of the work so that we can verify the wiring is correct. Keep in mind that plugging an extension cab into the jack will change the impedance that the output transformer sees. If your amp has an 8 ohm speaker and you plug in an 8 ohm extension cab, the load on your OT is now 4 ohms because the speakers are in parallel. Some amps can handle running at a different load impedance while others may give you trouble if you don't match the speaker impedance to the amp's impedance.
     
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  3. Dostradamas

    Dostradamas Tele-Meister

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    Your "out" from the speaker will be AC not DC like your signal path.

    Running AC into any other input will cause issues.

    If you are wanting to plug a speaker into that jack it will always be mixed with first speaker (ohms, wattage)


    What are you wanting to run this amp output into?
    Another amp?
    Speaker?
    Processer?

    I put 2- 1/4 jacks between the amp & speaker

    I run a speaker cable from one to the other for stock set up

    I can run the amp into a separate cab or run a separate amp into the speaker.




    If you just want to add another 8 ohm speaker that wiring will work.

    2 - 8 ohms in parallel = 4 ohm

    It also changes the wattage rating.

    2- 30 watt speakers in parallel = 60 watts

    The lower the Ohms of your speakers the more your amp pushes out.
    some amps are designed to handle 2-16 ohm loads without trouble.
    Too low an ohm load will cook your amp quick.

    Confirm your amps lowest output ohm rating and stay above that.

    What amp are we talking about?
     
    Last edited: May 6, 2021
  4. 440mhz

    440mhz Tele-Meister

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    It's 5 watt 5V Crate amp with a 30 watt Celestion Speaker. This company is no longer in business and I can't finding more info. The ext cab I s a Fender SC 122 Encloser: (12" Celestion® G12P-80 Speaker
    Impedance: 8 Ohms). The speaker in the Crate amp plugs into amp with a 1/4 jack and I've tried connecting the Enclosure as well, that works as well. The speaker is hidden from the back, so I can't take a pic.
     
  5. Dostradamas

    Dostradamas Tele-Meister

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  6. Dostradamas

    Dostradamas Tele-Meister

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    I would stick to a 8 ohm load to be safe.

    If you are already running both at the same time without excessive heat you may be ok

    You may also not be pushing it hard enough to get a fire started

    If you can play cranked for over an hour without it getting really hot your probably fine.
     
  7. 440mhz

    440mhz Tele-Meister

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    Thanks, funny thing is though the has only 1 12ax7a tube and not 2 as the system block diagram shows. Maybe that why they are out of business. Thanks all.
     
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  8. 440mhz

    440mhz Tele-Meister

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    Ya I'm not pushing it. I'm in a apt. and can't turn it up. I've disconnected the speaker in the amp and I am using the Enclouser by it's self. I always found the 10" 30 watt Celestion has a bit to much treble anyways. Thanks again.
     
  9. Forthefunofit

    Forthefunofit TDPRI Member

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    The system block diagram isn't showing 2- 12AX7 tubes, it is showing the 2 halves of one twin-triode tube.
     
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  10. 440mhz

    440mhz Tele-Meister

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    It loks like i"ve got some learning about valve amps. Thanks.
     
  11. Forthefunofit

    Forthefunofit TDPRI Member

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    Don't we all! But I don't intend to stop learning until they plant me.
    Just a few years ago reading an amp schematic was as foreign to me as trying to read ancient Hebrew. :)
     
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