I have just bought an enclosed 1/4 inch mono jack for a small amp cab I am building, but it seems to have 3 connectors on it. The earth connector is nice and obvious, but there are 2 more on the back of the jack and I don't know which one is positive. I read on a site somewhere that I may have to test both of them to see which one is correct, but I don't know if that is necessary, or how that is done. Any help would be much appreciated as always.
Got a part number? Googling the data sheet for the jack will probably get you the answer.
Got a meter? It's easy to test with a meter and a guitar cable. Alligator clips would be nice, but not necessary.
First test without the cable. Set your meter to some middling resistance range. Place one lead on any one lug and try the other lead on both of the other lugs. Go around to find if it reads 0Ω (This is not the same thing as OL) between any pair.
Now plug in the cable and do the same thing. Then, put one probe on the tip of the cable and check to see which of the 3 lugs gives you 0Ω to there. Check the sleeve of the cable as well, just to be sure.
You could make do with a battery, led, and resistor in a pinch. There are a couple ways to do an audible test as well, but if you're going to do much wiring at all, you really should get a sensible digital meter.
Thanks for that detailed reply, I appreciate it. I don't have a meter, or any of the bits you mentioned there, and you are right, I should get some as I seem to be doing this sort of thing more and more, even though I don't understand it to the depth of most guys on this board.
In the end I've opened the switch up, which is probably what I should have done immediately; I can now see which connector goes to the tip, so that is good, but I have no idea what use the other connector is for!
Hi Gary... ...while you have the beast in bits, it may be also worth your while to plug in a stereo jack (TRS - tip, ring an sleeve) and see whether your "other" two contacts align with the ring and the sleeve....that could give you another clue as to what goes where and which of these best suits being connected to the 'sleeve' of a mono plug... sometimes I have experienced mis-alignment of contacts when using a mono plug in a jack that was designed to accept a stereo version...
...although more likely A-C is correct in suggesting there is a 'switching' circuit built in there, that is actuated by the action of inserting a jack plug...things like this are more often used to turn a power circuit on when a plug is inserted, and off when it is removed... save yourself a heap of grief and buy a meter...a basic one that checks continuity and resistance costs peanuts, and you can always upgrade another day when you get to the point of being able to wire your own nuclear power station..
Cheers from Oz!
More than six guitars?
..it's only an addiction if you're trying to quit...
Post by teddiestrat on May 11, 2010 11:30:20 GMT -5
I recently fitted something like what your describing to a guitar and i use the connection closed to the opening as the ground and the furthest away as the live. It is infact a stereo Jack but will serve a mono postion also.
the one i fitted was filled to a PCB and i removed it to facilitate a need