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Question regarding simplistic electronics for jack plug

My speaker wires are marked for both positive and negative where they connect to the speaker assembly at the back. I picked up some 1/4" mono jack plugs today to use on a stomp box or two that I have in various stages of completion.

I have not piddled with any electronics hook ups like this and I am wanting to know just where to correctly connect each wire for the speaker at the jack plug. It looks as if the jack plug has 3 different metal contact points on it. There are two are of the same size metal contacts, but there is one shorter one on the plug, too. None of them are marked positive or negative leads.

This is probably something really simplistic, but I didn't want to screw it up when solding the wires to the contacts on the jack plug. Does it matter as to the conncetion of the positive and negative speaker wires on this plug? What is the purpose of the shorter contact on this jack plug? Is it for grounding or such?

Thanks for any advise. I appreciate it.

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Permalink Reply by James Huey on September 12, 2014 at 3:56pm

I had to go dig up the package I had gotten, but both packages list the parts as 1/4" mono on them. The interesting thing is that one package shows a jack with only two connectors and not the three that these photos show. Perhaps I picked up the wrong thing completely, but the sales person didn't know squat about what she was selling and I have not piddled with guitar electronics in the past. These are 274-0255 (the one shown in photos) and 274-0252 at Radio Shack. Are these totally wrong, as they are 1/4" mono phone jacks? Be just my luck I got the wrong item. :-(

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Permalink Reply by robert jones on September 12, 2014 at 11:37pm

That is a switching jack.

It can be used in an amp to turn it on or off when a cable is plugged in, especially good for battery powered amps.

To use it as a mono jack wire as usual and ignore the switching tab. You can clip the switching tab off after you determine which lug goes to it.

I would buy 1/4" mono jacks and keep this for the battery powered CBAmp you know you want to build. :-)

(If by "stomp box" you mean effects pedal carry on with this jack and search over on DIYstompboxes for more info.)

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Permalink Reply by robert jones on September 13, 2014 at 4:03am

When a cable is plugged in the tip separates the two tabs. This is the switching action whether it is on or off depends on wiring.

Most useful in battery powered devices as a battery bypass switch; open = battery connected, closed = battery disconnected.

If wired that way pulling the guitar cable plug from the amp disconnects the battery and ensures it won't accidentally get turned on.

You can find wiring information at the DIYstompboxes site since these are common in effects pedals.

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Permalink Reply by James Huey on September 15, 2014 at 6:38am

I found this YouTube video that explains the basic electronics pretty well. There are others, but this one seemed to get to the point and shows the jack being a two pronged style jack instead of the 3 pronged one shown in my photos. Hope it loads, as I think it helps.

http://youtu.be/K33Xj95095I

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Permalink Reply by James Huey on September 15, 2014 at 6:46am

This is the jack I'll likely use at present, as it seems pretty straight forward in setting it up as per the video.

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Permalink Reply by robert jones on September 15, 2014 at 9:24am

These new photos are a standard 1/4" mono jack, different item than in your first photos.

When viewing it as in the bottom photo the lower (left) tab is positive and the upper (right) tab is negative.

I think you may be on to something with using YouTube as your source for help.

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Permalink Reply by James Huey on September 15, 2014 at 12:03pm

I wish that the threaded ends on these were longer, as I have to cut down the sides of my stomp boxes to use them. Not so for the length of most of my CBGs, but certainly a fact in making my stomp boxes out of wooden cigar boxes. I got too rambunctious with my first stomp box that I used these on and split the wood in trying to cut away some of the wooden side material. Oh, well, I learn as much from mistakes as I do a total success on the first go.

Thanks for the info on them. The problem I have with YouTube videos is that you have to plug in the exact correct search name or you can miss something that may have just hit the spot for what you were looking for. Similar here, as there is just so much information and much is contained in some other topic than what you may be looking for.