Battery snap shorts on box. Positive ground build.

Focalized · April 14, 2009, 02:23:17 AM

When the battery snap touches the box it cuts the effects sound.

Using a combo of the PNP wiring from GeneralGuitarGadgets.com:

And this switch wiring:

Should I have followed the GGG layout fully? Or is this normal? Shouldn't be.

anchovie · April 14, 2009, 05:35:02 AM

Is this with the battery connected to the snap or running off a PSU and having the snap loose in the enclosure?

Andi · April 14, 2009, 07:38:59 AM

Tape it off?

MohiZ · April 14, 2009, 08:34:50 AM

It's because only the positive terminal of the battery is disconnected when using the DC jack. On a negative ground build, this prevents the snap from shorting, but on a positive ground build you'd need to have the negative terminal disconnected.

The way I see it, the only way around this would be to have DC jacks with the lugs swapped, but I don't think those exist. Or use a center positive DC plug, and wire the battery snap the other way around. You're probably best off just taping the snap as suggested.

megadan · April 14, 2009, 12:32:01 PM

Quote from: MohiZ on April 14, 2009, 08:34:50 AM
It's because only the positive terminal of the battery is disconnected when using the DC jack. On a negative ground build, this prevents the snap from shorting, but on a positive ground build you'd need to have the negative terminal disconnected.

The way I see it, the only way around this would be to have DC jacks with the lugs swapped, but I don't think those exist. Or use a center positive DC plug, and wire the battery snap the other way around. You're probably best off just taping the snap as suggested.

Agreed, I usually put a piece of tape over the battery jack when it's not in use, even in a neg ground circuit. You never know what will come loose in my shoddy builds

so better safe than sorry, it's just a little piece of tape

Andi · April 14, 2009, 02:42:46 PM

Even in normal ("negative ground") circuits it's worth taping off - it can still short things to ground!

Focalized · April 14, 2009, 11:52:27 PM

Thanks for the info.

Yeah it shorts when i'm using my Pedal Power 2 supply. Just wanted to make sure the wiring wasn't an issue.

I though I could get some really cheap battery snaps and cut off the snaps. Use them on the box if I don't have a battery in it.
Or just get the ones that snap on a battery to cover the posts.

Andi · April 15, 2009, 03:11:50 AM

Why not just a bit of masking tape?

Focalized · April 15, 2009, 03:50:30 AM

No reason. I just like parts I guess. If I sold it or others I'd like it to have something permanent to block it from shorting.

MohiZ · April 15, 2009, 06:48:10 AM

One thing I've found nice is a battery adapter for connecting a 9V battery to a DC jack on the outside of the box. It's basically just a snap with a piece of cable and I got it as a compliment from this German store I always order from. When you have one of those you don't have to have a battery snap inside the box, which is useful when using small enclosures that couldn't accommodate a battery inside them!

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Battery snap shorts on box. Positive ground build.