Thinline 2.1mm DC Jack Wiring?

[natron_mn]

I bought a few 2.1mm dc jacks from Small Bear, and was wondering how I wire them? One of the terminals appears to be longer than the other. I'm thinking that's the positive, and the shorter one is ground?

[vigilante397]

You are correct. The shorter terminal is the center connection, which for guitar effects is negative, and the longer is the barrel connection, which for us is positive.

[natron_mn]

Excellent - thank you!

[duffrecords]

You can confirm this with a multimeter, which is an indispensable tool for this hobby.

Sent from my XT1254 using Tapatalk

[natron_mn]

I've tested 1/4" jacks to determine tip/ring/sleeve with a multimeter and patch cable before, but I'm unsure how I would do that with a dc jack.

[vigilante397]

Pretty much the same way as you would a 1/4" jack. Set it for continuity, put one probe on the center pin of the jack then the other probe on one of the lugs on the back to find out which one it is connected to. Effects pedal power supplies use center negative, so whichever lug is connected to the center pin is your negative lug.

[thermionix]

Is that one of the switched types?  It gets a little more complicated if used in conjunction with a battery.  You want to cut the battery off when you plug in external power.  Wire it wrong, and you could 'splode your battery.

If that just has two lugs, it's not the switched type, and disregard what I just said.

[ColScot]

vigilante397 thanks for clearing up what should be positive and negative but for natron and anyone else (and me  ) some 2.1mm are wired centre positive and a lot of transformers are wired centre positive. there is usually a mark on the transformer to tell you which one.