Author Topic: Pedal DC power jacks  (Read 1483 times)

jmsmusic

Pedal DC power jacks
« on: July 03, 2008, 05:35:02 AM »
Hey guys, just a question ive gotta ask.

http://www.futurlec.com/DCPower-ChassisMale.shtml

Would these suffice? 2.1mm (the first one, metal chasis)

or are these better?
http://Http://www.smallbearelec.com/Detail.bok?no=666

or is there a better alternative out there?

Thanks loads!

96ecss

Re: Pedal DC power jacks
« Reply #1 on: July 03, 2008, 06:59:43 AM »
Hi and welcome aboard.

I don't know about the one from Futurlec, but the one from Smallbear you linked to has the external nut. That means that most of the jack will be sticking outside your pedal. That may be what you're looking for but it's different than the one from Futurlec. This is the one I use from Smallbear http://www.smallbearelec.com/Detail.bok?no=93. At $1.25 they're cheaper than the ones from Futurlec and they work great.

Dave

ambulancevoice

Re: Pedal DC power jacks
« Reply #2 on: July 03, 2008, 07:19:35 AM »
get the small bear on
the futurelec ones are non plastic therefore no isolated from the enclosure, which is one thing a dc jack need to be (unless your using a negative shell and positive tip power supply)
the small bear one is plastic (except for the nut)

Open Your Mouth, Heres Your Money

Roobin

Re: Pedal DC power jacks
« Reply #3 on: July 03, 2008, 07:24:47 AM »
If you have a search through past posts, you'll find that there are a couple of potential problems using metal jacks. The way most DC plugs are made, the barrel/outside is positive i.e +9v and the inside is 0V/ground. Now, assuming you're using a metal box, this poses a problem, since your audio 6.35mm jacks and circuitboard will be grounded to the box itself, which acts as a 'shield' against RFI/interference. Thus your metal box is at 0v/ground. However, by using a metal dc jack, the thread of the jack connects to the box. This thread also connects to the barrel of the jack. Which is at 9v+. So obviously there's a problem there, and your pedal won't work. How to solve this? You could

i) Use a plastic box thereby avoiding the power issue, but leaving you less shielded than a metal box (although this could be solve by the use of a metal plate in the top of the box, or some alu foil/paint. See http://www.muzique.com/lab/magpaint.htm.)
ii) Use a plastic jack, so that the barrel is insulated against the box. This is the easiest option.
iii) Use a metal jack but drill out the thread hole for it slightly larger, so you could put filler in there and drill another hole for your jack thus insulating it against the metal box, or cover the thread in heatshrink and the the bits where it touches the box. This is by far the hardest option.

So in answer to your original question, I'd go for the small bear plastic ones.

jmsmusic

Re: Pedal DC power jacks
« Reply #4 on: July 03, 2008, 07:50:49 AM »
aye, understood! Thanks for the help guys! My doubts are cleared. haha.

cheers,
James

Cardboard Tube Samurai

Re: Pedal DC power jacks
« Reply #5 on: July 03, 2008, 04:54:35 PM »
effectsconnection.com have some good ones