9V DC jack problem

[elfen]

hi,

https://www.addison-electronique.com/catalog/images/101276.jpg
I bought this DC jack thinking I could wire a 9V battery snap to it, to put in a little guitar preamp. The problem I have is I can't figure a way of connecting it. I attached a picture for reference.
When no jack is connected, pin 1 and 2 are connected together, which, i think,  would make pin 3 the ground (tip of jack), and pin 2 would be the +9V to the board and pin 1 the battery positive lead. But, when you connect a jack in, pin 2 and 3 get connected together, which would disconnect the battery and link the ring of the jack to its tip...? Working the other way around, if pin 2 is the battery positive lead and 1 is the +9V to board, then pluging a jack would connect the battery + it's negative.

Am I right to think this jack is of no use for this purpose ? If this is the case, is there a way to trick it so it works?

many thanks

[bsmcc2010]

That's a metal jack. Almost all effects pedals are powered by positive sleeve jacks meaning that unless you isolate this (rubber washers or something) then the signal will ground to the case, unless the case is not metal of course.

As you have labelled it, usually on an isolated/plastic jack 3 would go to ground, 1 to the 9v input of the circuit board and 2 to the positive lead of a battery snap. This means when a powerjack is inserted the battery is disconnected so that you don't connect 18v up to it and also it doesn't waste your battery power.

So basically unless you can find a way to insulate it from the case, get something like this

http://www.ebay.co.uk/itm/2-x-Boss-Style-DC-POWER-JACK-SOCKET-2-1mm-Center-Pin-Switching-Stompbox-DIY-/230730654696?pt=UK_Guitar_Accessories&hash=item35b89e63e8#ht_500wt_1219

[alparent]

But for your little amp. Is your power adapter + on the pin or + on the sleave?
What are you attaching this jack to?...plastic...metal....wood?

[elfen]

i'll install it on a plastic case, + being on the sleeve. The thing is this female jack is not even installed and the pin 2 goes to pin 1, but, when you connect a male jack in, pin 2 goes to pin 3.
I think I'll just go with a plastic jack instead.

[elfen]

it acts like a 1/4 female stereo jack where the tip gets connected to ground when you unplug, so that no "pop" sound happens, and the sleeve and ring get connected together when you connect a mono male jack to it.

[alparent]

did you test the male jack? it might be shorted?

[elfen]

genius! thanks!
I feel stupid right now...