Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups

Multi-tap output transformer jack wiring.

Discussion in 'Shock Brother's DIY Amps' started by fakuverymuch, Jan 23, 2013.

  1. fakuverymuch

    fakuverymuch Tele-Meister

    The 5e3 Mojotone amp kit I ordered comes with a multi tap OT.
    Is this how I would wire it to use all three taps?
    Also... If I plugged my 8 inch 4ohm speaker into the appropriate jack, could I also have the 12 inch 8ohm speaker plugged in at the same time? Or would this damage the OT? Or do you have a better Ideal? I don't have any other cabs other than a practice amp with the 4 Ohm Weber in it, that I would also like to use for lower volume playing.
    Thanks for sharing your knowledge.
    Last edited: Jan 23, 2013

  2. pasquale

    pasquale Tele-Meister

    Jun 14, 2010
    Boston, MA
    The ideal scenerio would be to wire One speaker jack to a switch, a second jack wired to the first as an extension jack and the transformer to the switch. That way you can choose your impedance based on whether or not you have an extension cab hooked up or different ohmage or whatever.

  3. vanr

    vanr Tele-Holic

    Oct 20, 2003
    Looks fine to me although I'm not sure of the color codes on that OT, but it should be fine. I don't trust switches myself and always wire up 3 output jacks. No I wouldn't plug in both those cabs at the same time.

  4. Badside

    Badside Tele-Meister

    The only issue with that wiring is that you don't have a "default to ground". If you turn it on without a load connected, it's an open circuit which is much worse for your output transformer than a short circuit.
    That's why most people use a shorting jack and an impedance switch.

    That said, I never uses switches, I don't trust them. There is a way to have two different taps and still have a default to ground. Doesn't work with more than 2 taps though (and one jack per tap).

    Do NOT hook different speakers to different taps at the same time.

    Technically, you may be able to run both the 8 and the 4 into the 4 tap, although you will go out of your amp's "comfort zone", lose power, and the 8 will receive half the power the 4 is receiving.

    It's always much better to pair speakers of similar impedance.

    If you still want to use both at the same time, use a parallel-out jack on the ext cab, or a "Y-cord" (mono-to-mono, very important).

  5. fakuverymuch

    fakuverymuch Tele-Meister

    Ok Thanks a lot guys. You are a wealth of information.
    Is this how you would do it with a default to ground?
    Although the switch seems like a more elegant route to go. (but not as safe, so I just found out)
    I guess I would need a 3 Way rotary impedance switch. Or could I use a DP3T ON/ON/ON switch for this?
    To further complicate the issue...if I wanted to hook up a negative feedback loop with three taps, would each tap go to a nonshorting jack? From what I could glean off of the web; The NFL comes off of the tap that the resistor is spec'd for and always gets a signal regardless of which tap you are using.
    Is this correct? Thanks

  6. jhundt

    jhundt Poster Extraordinaire

    Mar 23, 2003
    you know that the Fender 5E3 had none of those options/gadgets, and those amps sounded so good that thousands of people are building copies.

  7. Badside

    Badside Tele-Meister

    That won't work: as soon as you unplug the 4ohm, the whole thing gets grounded. You can't use 8 and 16 by themselves. (If one tap is grounded, effectively all taps are grounded).

    The switch is not unsafe per se, it's been unused thousands of time by thousands of people with no issue. I'm just anal about this stuff...

    There is a way of getting default to ground with two taps and two jacks, but I can't find a drawing and I can't accurately describe it (it's kind of a mind bender at first, effectively one jack grounds via the other, meaning the default to ground is lifted as soon as one jack is in use, it requires 4-lugs Cliff type jacks to work)

  8. Badside

    Badside Tele-Meister


    I would stick with stock wiring

  9. fakuverymuch

    fakuverymuch Tele-Meister

    Ok. At the risk of aggravating you guys even more.:lol:..........
    How about one of these schemes? Would they work?
    I promise I won't come up with any other hair brained schemes.

  10. pasquale

    pasquale Tele-Meister

    Jun 14, 2010
    Boston, MA
    That's how i do it. In fact it reminds me that i should do it tonight on my first ever build, because at the time i had nonidea how to do it and just used two seperate jacks with neither one switching, which we already know is a bad idea, i have seen guys turn amps on not plugged into speakers plenty of times, including myself and including that first build. They do sell rotating switches if you want to use all three taps, but unless you plan on switching from 6l6's to 6v6's and always random speaker cabs you can probably live the rest of your life without that 16 ohm tap.

  11. fakuverymuch

    fakuverymuch Tele-Meister

    So would a 6amp 120VAC SPDT mini toggle switch handle the current without burning up?
    What do you use? I also have one with that rating, that is a SPDT-3 position on/on/on switch. I Could use all three taps then.
    A proper rotary switch would be best, but I am just thinking about availability.
    Hey may be I could get this one....

  12. pasquale

    pasquale Tele-Meister

    Jun 14, 2010
    Boston, MA
    That switch looks legit. I just rewired mine and I use the Carling "ground" switch i may pick up one of those switches you linked to though if I get a project going with three taps.

  13. fakuverymuch

    fakuverymuch Tele-Meister

    That rotary switch requires a half inch hole. To bad because it is relatively cheap. But I also have a Carling ground switch here.
    So that is what I will use for just the 4 and 8 Ohm taps.
    Take it easy.

  14. Bill Moore

    Bill Moore Tele-Holic

    I used a Marshall switch with my "Twin" build, and added another jack to use as a series as well as the parallel speaker hookup. With my current "Deluxe" project, I'm using a SC13A switching jack in the aux. position, and a standard shorting jack in the main. I figure I'll only need 4 and 8 ohm taps, and always use the combo speaker. Look at an 80's fender schematic to see how to wire it.

  15. fakuverymuch

    fakuverymuch Tele-Meister

    Final design. Any flaws?

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