Wiring a DPDT like a SPST

All frequent questions on switching: true or not true bypass, transistor-based or mechanical.
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Sadcadaver
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Post by Sadcadaver »

I've a question, it probably has a pretty simple answer but being slightly thick I can't find it on my own.

I'm re-housing a cheapie Daphon EQ pedal, and the footswitch appears to be a tiny little tactile spst switch. It only has two wires going to it anyhow.

Anyway, I obviously want to swap it out for a more substantial footswitch, but couldn't find any nice big chunky SPST switches, so I thought I'd buy a DPDT and use that. All pretty straightforward so far eh?

Except the best I can get is having to press the switch twice to turn it off, and twice again to turn the damn thing off. I've tried a few different ways of jumping the connections, but it's not happening :hmmm: . I've googled, and this question appears to have been asked before, but not answered sufficiently.

I know that there will probably be a simple solution to this, but I need one of you fine people to tell me!

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mysticwhiskey
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Post by mysticwhiskey »

Sounds like you needed a momentary switch but have used a latching switch instead. You're going to need to get the correct switch, there's no way to make the one you've got work I'm afraid.

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Sadcadaver
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Post by Sadcadaver »

Oh, right then. That's no problem, I'll just buy a momentart switch then. I wasn't expecting that, I didn't think a momentary switch would stay on once it was depressed. I'll give it a bosh anyhow. Thanks Mysticwhiskey! :thumbsup

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Post by Barcode »

Sadcadaver wrote:Oh, right then. That's no problem, I'll just buy a momentart switch then. I wasn't expecting that, I didn't think a momentary switch would stay on once it was depressed. I'll give it a bosh anyhow. Thanks Mysticwhiskey! :thumbsup
It doesn't, which is why it is momentary. But not all switching systems want the switch itself to stay connected. For example, Daphon pedals generally (like a lot of companies) use a momentary switch wired to trigger a jfet flip-flop switching arrangement. so you only want a momentary switch, because the siwtching circuitry is looking for just a tap to ground, not a latch.

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Sadcadaver
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Post by Sadcadaver »

Cheers Barcode. You lost me a jfet flip-flop :scratch: , but I get the gist of it. It's all a learning process for me!

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Post by Barcode »

go to geofex.com and dig through there. There is an article on there about flip flop switching. But for what you are asking here, it's enough to know that the pedal you are using has jfets arranged to do switching instead of a big switch. the only thing that momentary switch does is trigger the electronic switching.

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