True Bypass Loop Strip LED Question

[sixstringphil]

I'm working on a TB loop project similar to the one on singlecoil.com. Quick question about LED hookup: His diagram shows the resistor on the negative side of the LED. I was told that the current limiting resistor should always go on the positive side.  Is there a rule/theory on this?

here's a link to the diagram:
http://www.singlecoil.com/tb-strip/dia1.html

[juse]

I always put it on the + side, but it will work either way.

[darron]

it doesn't really matter which side it goes on, as it's still going to divide current.

i personally use the negative side because i also use the 3pdt switch to ground the 'send' when in bypass.

give this a shot:
link

[sixstringphil]

Well, I know this is a simple circuit, but I'm still having some problems. None of them will light when the ground is connected on the switch. I've got 1k resistors on the (+) side of each of 5 LEDs. Is that an incorrect value because of the parallel circuit? Nothing is lighting up, and I'm getting mVs on the DC jack.

I should mention that these are normal 5mm green Radio Shack LEDs.

[sixstringphil]

Well, it suddenly started working. I must have a loose connection or short somewhere.

[5thumbs]

Well, it suddenly started working. I must have a loose connection or short somewhere.

Are you using a metal enclosure and DC power jack in your TB loop strip?  If yes on both, is the body of the DC power jack metal or plastic?

The reason I'm asking is that when I built a TB loop switch box a while ago, I used a spare metal-bodied 2.1mm DC jack with an aluminum enclosure.  I had the same problem you described until I realized that the body of the DC jack was shorting to the enclosure.  I ended up enlarging the hole for the jack and carefully insulating the jack body with heat shrink tube.  After that, everything worked fine.  This incident was also the cause of me swearing off metal-bodied DC jacks unless I really need to use them for a specific project.

[sixstringphil]

5thumbs,
No, it was a plastic DC jack. I also learned that the hard way on my first build. I think the problem was a junction I made for the 5 LED hot wires to connect to the DC jack. It may have been grounding against the case. I insulated it all, and now seems to be fine.

Thanks!!