Lost with rotary switch terminology... can anyone help me here?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Che_Guitarra, Apr 13, 2015.

  1. Che_Guitarra

    Che_Guitarra Member

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    Not sure where to put this, but I figure amp tweakers are probably the first place I should try.

    Looking to replace a DPDT on-on-on toggle switch with a rotary switch (with 1/4" shaft) - the smaller the component footprint the better. Problem is i've got no idea how to translate DPDT on-on-on into rotary switch terminology... poles, decks, positions... aaargh... i'm lost!

    Can anyone help me out?
     
  2. AXEnGEAR4J

    AXEnGEAR4J Supporting Member

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    (Double Pull Double Throw) On - Off - ON

    Just take a test meter and check the continuity of your terminals if not marked. They are both the same thing as a toggle switch only it has a rotary.
     
  3. Jeff Gehring

    Jeff Gehring Silver Supporting Member

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    Double pole means two independent switches, double throw means that the common contact of each switch has two contacts it is switched between.

    Moving to rotary switch parlance, each deck usually equates to a separate switch, but there are also decks that have multiple switches on them. They will still identify the number of poles, which is the important thing. If you wanted to duplicate a DPDT toggle switch with a rotary switch, you would want a 2 pole switch, with two positions. Most probably the switch will have more positions than that on each deck, but most rotary switches come with a movable mechanical stop to limit the number of positions that are actually able to be used.
     
  4. wyatt

    wyatt Member

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    1) ON-ON-ON means you want 3 positions. Many rotary switches are designed so you can limited the number of positions mechanically...so you can buy a "3 position switch" or you can buy a "2 to 12 Position" (or whatever to whatever) switch and set it to only allow three positions.

    2) Double Pole is double pole (2), that's a minimum for you, you can buy triple pole (3), quadruple pole (4) or even duodecuple (12) pole, and only wire two of them.

    3) Shorting "make before break" or non-shorting ("break before make"). I use Shorting in audio...it makes the connection to the next pole before breaking the connection to the previous pole, this means fewer "pops."

    4) Extra decks only matter if you need them, either for more poles or for organization purposes.

    As with #4, form factor is a big deal depending on application and room available.
     
  5. Jeff Gehring

    Jeff Gehring Silver Supporting Member

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    A good way to think of an ON-ON-ON implementation in a rotary switch is to consider a Telecaster selector switch.

    The Tele selector is essentially a rotary switch turned on its side, with one deck and two poles, each pole having three positions.

    The commons (wipers) of the two poles are wired together. On pole 1 (one side of the wafer/deck) position 1 is wired to position 2. On pole 2 (the other side of the deck) position 2 is wired to position three. So with the selector in position 1, the pickup connected to pole 1, position 1 is routed to the common, which goes to the volume pot. In position 2, both pickups are routed through, and in position 3 only the pickup connected to pole 2 position 3 is routed through.
     
  6. TimmyP

    TimmyP Member

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    I don't think I've ever seen an On-On-On toggle switch (a Telecaster switch is not a toggle switch, but rather a lever switch).
     
  7. rumbletone

    rumbletone Silver Supporting Member

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    They are typically like this: http://www.tdpri.com/forum/attachme...-dpdt-switch-pu-selector-switches2_diag_4-jpg

    Before recommending a rotary configuration, I'd want to know what the switch is doing - there are different ways to wire a dpdt on-on-on - for example, they can be wired as a 3-way single pole switch, which would impact which rotary configurations can be used. Also need to ensure the switch is appropriately rated for the signal.
     
    Last edited: Apr 13, 2015
  8. Che_Guitarra

    Che_Guitarra Member

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    It's the mode control switch on my Sustainiac system. Definitely DPDT on-on-on: there are three different modes to select from (1) fundamental sustain (2) harmonic sustain (3) mixed sustain. Here's the exact component in the circuit:

    [​IMG]



    i'm not really a fan of superfluous controls on pickguards, I like simplicity and minimalism. Just seeing if I can move the function onto a rotary switch, and then into the pot location of a strat's second tone knob (which is redundant now I have a master tone control).
     
  9. rumbletone

    rumbletone Silver Supporting Member

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    Thanks - my initial thought is that it could be replaced with a 2 pole 3-position rotary, but I'll see if I can figure out the wiring. Do you know what each of the 4 leads connects to? From the note re keeping the wires separate, I'm guessing the pair on the left is DC power?
     
  10. rumbletone

    rumbletone Silver Supporting Member

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    Hmmm.... not seeing how an on-on-on would work on the right bank of lugs - since the red and black wires would always be connected directly. If it was on-off-on, they would be connected directly in up or down position, but in middle position the signal would travel through the capacitor. What are you confident that it's an on-on-on - does it say that on the side of the casing of the switch?
     
  11. rumbletone

    rumbletone Silver Supporting Member

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    Sorry - I can't figure out what the switching is doing if it's an on-on-on switch, since it would appear that the black and red wires are always directly connected in an on-on-on configuration, which doesn't seem logical. If you could let us know how you confirmed that it's on-on-on (documentation, it's written on the switch casing, you removed the switch and tested continuity, etc.) that would assist. Thanks!
     
  12. Che_Guitarra

    Che_Guitarra Member

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    It's confusing me too. Just enough complexity to the system that I can't quite work out what's going on.


    I've sent an email to the Sustainiac people so hopefully they can clear things up.
     

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