DC Power Problem

[charles]

Hi guys,

I'm new to the forum and have just finished my first pedal build (tonepad.com LPB-2.)

Since I power my pedals with Pedal Power, I've incorporated a DC jack into this circuit.  However, for some reason, it doesn't power up using DC power.  9V battery works perfect, but not the DC.

I initially thought I made an error wiring the jack so I double checked and even snapped on jack open to see I've made the right connection.

I've just desoldered the jack and checked again by connecting the wire that's going into the circuit with positive wire from the battery snap and the LED lights up.  However, when I connect the same wire to the outer barrel of the DC jack that's coming out of Pedal Power, the LED doesn't light up.

What can be causing this?
I've made LPB just as described on tonepad.com.

I would appreciate any input from all you experts out there.

Many thanks in advance!!!

[niftydog]

do you have a multimeter? The first thing to do is remove the mystery from your problem. Use a multimeter to actually measure what you've got (or what you don't got!)

It could be that you have the polarity incorrect, or even that you have wired the supply directly to ground somehow.

It's kinda hard to know what's wrong for us here on the forum, all you can do is work through it systematically and eventually you'll find the problem.

[Paul Marossy]

It could be that you have the polarity incorrect, or even that you have wired the supply directly to ground somehow.

I thought of that as well, but wouldn't the rest of the pedals connected to that power supply not work as well? You know, it would short out the power supply to them all... or would it?

[Torchy]

crp

[niftydog]

thought of that as well, but wouldn't the rest of the pedals connected to that power supply not work as well? You know, it would short out the power supply to them all... or would it?

not sure of the topography of the Pedal Power, but I suppose it's possible to short one of the regulators, putting it into shutdown mode, whilst the rest of them are operating correctly.

[Paul Marossy]

not sure of the topography of the Pedal Power, but I suppose it's possible to short one of the regulators, putting it into shutdown mode, whilst the rest of them are operating correctly.

Well, when you put it that way, I guess that is entirely possible.

[Alex C]

That's happened to me, Paul- I use 2 OneSpot adaptors and daisy chains, and they all shut down when shorted.  

From the VoodooLabs website: " Like the original Pedal Power, each of its eight outputs are completely isolated, short circuit protected, regulated and highly filtered."   So I guess that's not the problem here.

What kind of jacks are you using?  

Alex

EDIT: I shouldn't have said "I guess that's not the problem here.  It could very well be the problem, all that the information above shows is that even if the other pedals function properly, the polarity of this pedal could still be reversed.  I need to take a multimeter to my brain; sometimes I think the polarity is slighty off in there.

[Rodgre]

Lots of things could be wrong here. The meter will tell all!

1.  The polarity could be reversed. The inside (tip) should be negative and the sleeve of the DC plug should be positive.

2.  Certain DC jacks (and really, any that you should use in a pedal that also has a battery clip) have a switching mechanism in them. That allows the jack to BREAK contact with the battery when the DC jack is plugged in. Thus, you are not sending 9v TO the battery, which would be a very bad thing.  You may have that miswired. A multimeter on Resistance setting will tell you what's what here.

3. Are you using a metal DC jack attached to a metal box? You really need to isolate the DC jack from the pedal enclosure (which is why I only use plastic DC jacks) because you'll be sending +9v to GROUND, which is a short.

4.  Some DC jacks look like the right size, but they're not. The inner dimensions of the jack might not be making contact with the plug.

5.  Is it possible that the cable from the pedal power to the pedal is bad?

I also use a Pedal Power on my board. I love it. Each output is isolated and allows for different voltages (simulating Boss ACA and PSA style adapters) and with the right cable, you can power PNP Fuzz Faces and other reverse-polarity boxes, as well as Line 6 stuff (requiring two outputs though.)

Good luck! Again, a meter will tell you all! I can't live without mine. Well, I mean, I can't do anything electronic without mine!

Roger

[Paul Marossy]

Alex C-

I use a daisy chain scheme, so in my case, it's very obvious if I get the polarity reversed on something...