Pedal Gurus! Power Supply Question

[Retro Hound]

I just bought a Way Huge Foot Pig fuzz pedal (for $30!) and the power cord that came with it is busted and taped back together, but still doesn't work. I'm not absolutely positive this is the original cord (I should have asked). It's an AC adapter AD-0006D (equivalent to AD-0003D/AD-0004D) it says. Input AC 120v 60Hz, 50mA. Output 9v 300mA. Polarity positive. I tried a spare adapter I have laying around. Input 120v 60Hz 12w Output 9v 780mA positive polarity. The light dims when I plug this thing in, so I don't think it's right. My question is: is the one that came with it right? Can I just run over to Radio Shack and get another one? From what I've found on the web, positive polarity is right. I don't find a manual online, but there may not be one. Or, I could just run off batteries.

 

[Ch0jin]

Hi Retro,
Nice score! I make germanium fuzz pedals and I can't even build one for that! I had a quick perv on the net and I note that it says "-9V" on the box right? I'm betting that means it's a PNP style fuzz (like a proper fuzz face) which means positive ground.

The thing about positive ground pedals is firstly they will NOT play nice with "regular" pedals. Make sure when you are trying the power supply out, that you are only powering the fuzz and nothing else. The next thing is how the DC jack is wired. It may be wired like a BOSS pedal (center negative), or it may be wired in reverse. The easy way to tell is with a multimeter. If you have one, your looking for continuity between the case, or the sleeve of your in/out jacks and either the center or sleeve of the DC socket. If you read continuity between ground (sleeve of signal jacks) and the sleeve of the DC jack, you can use a regular old BOSS compatible adapter. (Center negative) If you read continuity between ground and the center of the DC jack you'll need the opposite, i.e. center positive.

If you don't have a multimeter you can probably take it apart and figure it out from the wiring. Same theory as above applies, look for a common wire from the sleeve of the signal jacks going to the DC jack.

If you want to be ubersure, take it apart and Google the transistor types. A data sheet will say whether they are PNP (a positive ground pedal) or NPN (a "regular" negative ground pedal")

Hope that helps, I'm typing fast as it's time to leave work and go home and play with guitars

 

[duhvoodooman]

I would be stunned if the pedal used other than a center-negative adapter. That's been pretty universal in the pedal world for many years now. And I googled that adapter and found it on Amazon, which says it's center-negative, so any Boss-compatible pedal P/S (and they pretty much all are!) should work with the pedal.

The DiscoFreq pedal database says that it's "A sixty's style, negative nine volt, fuzz with germanium PNP transistors", so it should be run on a dedicated adapter, as Ch0jin said--you can't run positive-ground pedals on the same adapter with any negative ground pedals, or the power shorts to ground.

 

[Ch0jin]

Nice work DVM. Where I usually wax lyrical about the theory, you just cut through it to the answer.

Retro, Any chance you could put together a sound clip when you get it going? PNP Ge Fuzz's are kinda my thing (I've made like 6 of them and have 3 of them still at home) I'd love to hear how it sounds.

 

[Retro Hound]

Thanks guys. So you're saying I should look for an adapter that says Polarity negative? What it says on the adapter is Polarity: and then a plus sign with a line to some other symbol then a line to a negative sign. Should it be the other way around? I have some of those also.

This is my only pedal, the Vox VT-30 has about all the other effects I need/want/can handle. I can try making a clip, but I don't really play much, more like play-around.

I live in a small town so I was wondering if Radio Shack would have what I need or if one of my spares laying around will do.

 

[Retro Hound]

Here's some pics

 

[duhvoodooman]

Thanks guys. So you're saying I should look for an adapter that says Polarity negative? What it says on the adapter is Polarity: and then a plus sign with a line to some other symbol then a line to a negative sign. Should it be the other way around? I have some of those also.

Here's the symbol for a center-negative P/S, which is what virtually all modern effects pedals use:

Here's the symbol for a center-positive polarity P/S:

I would go with whichever symbol matches the one on the P/S that came with the pedal.

 

[Retro Hound]

Suddenly, it makes sense! Maybe because it's big enough I can see it now? It's a center neg.

 

[Ch0jin]

Wow, interesting gut shots! Full size pots, shielded input.

What intrigues me the most though is it appears to be negative ground. There's an exposed copper wire going from the center of the DC jack to the back of a pot. For a PNP Fuzz that's a little unusual.

Not that it matters though, I'd do what DVM suggested and match up your power supplies to the symbols and rock on