Closed circuit vs. open circuit jacks??

[moo cow]

probably a dumb question, but i went to the ratshack tonight to pick up a stereo jack and there were closed and open circuit options.  i'm pretty sure i want the open circuit, right?
thanks for the help

[R.G.]

It probably doesn't matter.

Open circuit jacks have just contacts for the sleeve (ground) and the tip. If you get the stereo version, there is also a contact for the ring, right behind the tip.

Closed circuit jacks have those same connections, but also have an internal connection that touches the tip (and ring, if stereo) contact inside the jack only if there is no plug inserted. That way, you can connect ground to this extra contact, and it will ground the jack's tip (and ring, if stereo) contacts when there is no plug in the socket, and therefore keep hum and noise from being picked up.

If you get closed circuit jacks and don't need the shorting capability, just ignore them, not connecting any wires to them and the jack will work just like an open circuit jack. The only difference is that the extra solder lugs make it confusing to find the right contact to solder to.