Can 9v Damage Pickups?

[j. pierce]

So I also build pedals (well, after my last two builds, it seems that apparently I just build bad radios, and then after a few hours of troubleshooting, beat them into submission as guitar pedals.) I just finished a Tremface copy using the schematics at Geofex. Anyway, it's a positive ground circuit, and I didn't have any stereo jacks for power switching, but I did have a jack with an internal (and isolated) switch. I decided that the easiest way to connect the other side of the switch to ground was to jumper the isolated switch to the sleeve connection, rather than running out to board ground.

Well, I made a boneheaded mistake and connected the isolated switch to tip. So when I put an input jack, the negative battery connection went through the circuit like normal, but the positive connection ran into the tip of the guitar cable rather than ground. I realized what I did, but not until after I plugged everything in and scratched my head. (Yeah, not the brightest move to plug something in w/o checking the connections first) Anyway, I got the pedal working after fixing the power connections and replacing a JFET.

But I'm wondering, can I/could I have messed up my p'ups by running the battery voltage through them? Looking at the schematic/layout (here - basically I've had the green wire coming back from the board to the input jack connecting at the tip, rather than to ground when a jack was inserted) I'm not sure if my p'ups actually saw voltage.

I only ask because I'm getting some wierd volume drops and sounds out of my rig today. I'm 99% sure that it's a patch cable, but I'm having a hard time isolating it, because the problems are so intermittent, and I haven't really sat down to troubleshoot it.

But regardless, would it even be possible to damage my p'ups if I just shorted a 9V across the input jack? I really have no idea, and I'm just curious now. My electronics knowledge is self-taught, and as such, incredibly spotty. I have a good grasp of a lot of things, but often times forget things which should be "the basics".

thanks.

[Dugz Ink]

It's basically just a coil of wire, and a 9 volt doesn't have much amperage, so I doubt it.

I remember magnetizing metal spikes by wrapping wire around them and then conecting both ends of the wire to a battery, but it took a while to have a semi-permanent affect... like dozens of hours. So, in theory it could have an affect, but I highly doubt that a few seconds would do it.

But I could be wrong.

Does it sound different?

[GodBlessTexas]

I'm going to have to agree that the 9v won't cause the problems you're describing. Nominal amperage of a 9v is what, 600 mA at best?

GBT

[KeithHowell]

Well given that most pickups have a DC resistance of greater than 3K ohm the formula V=I*R gives

I = V/R or I = 9/3000 I = .003 or less than 3mA and the greater the resistance the lower the current.So I don't think you would have damaged the coils.

Keith

[ansil]

i plugged a guitars pickups into the freaking wall man, and it diditn' hurt them. don't sweat it.

oh and in case you were wondering, yes it was on purpose and no one was holding it. but an ac cord and a guitar plug make a nice little toy for things not capacitor coupled.

PLEASE DO NOT TRY THIS I CAN NOT BE HELD RESPONSIBLE!!!!!!!!!!!!!!

ed

[BigG1986]

i plugged a guitars pickups into the freaking wall man, and it diditn' hurt them. don't sweat it.

oh and in case you were wondering, yes it was on purpose and no one was holding it. but an ac cord and a guitar plug make a nice little toy for things not capacitor coupled.

PLEASE DO NOT TRY THIS I CAN NOT BE HELD RESPONSIBLE!!!!!!!!!!!!!!

ed

Why on earth would you want to do that????

[erikbojerik]

If you had just a short circuit, it is possible the coil heated up some, then you might need to worry that you've melted off some insulation.