Devon Headen Posted November 24, 2004 Report Posted November 24, 2004 I'm going to be having a piezo element on the bottom of the bridge on my new guitar. My question is, where sould I ground the guitar? Grounding never quite made a lot of sense to me, so I'm sure there's an easy answer. If I drill a 1/4" hole and cut a piece of 1/4" round bar stock to fit in the hole, can I ground on that? Do I need to even ground on anything other than the output jack? Devon Quote
Dugz Ink Posted November 24, 2004 Report Posted November 24, 2004 If I drill a 1/4" hole and cut a piece of 1/4" round bar stock to fit in the hole, can I ground on that? A "ground rod" is a metal object that is able to dissippate RFI and EMI to a neutral point... which is usually a copper rod that is driven 1-2 meters/yards into the ground (ie: dirt), with only enough sticking out to facilitate attaching wires/clamps/etc. Putting a rod inside your guitar is not a ground rod; it's just a metal rod inside your guitar. As such, it can work as an antenna that attracts RFI and EMI... instead of neutralizing them. The "ground" connection on your output jack provides a neutral path that leads through the equipment and to the ground rod that the equipment is attached to via power cables. Since every piece of metal that is in your guitar has the potential to attract RFI and EMI, it's best if those pieces of metal are attached to the main ground wire. Also, your body (ie: human body) attracts RFI and EMI; grounding the bridge helps you to ground your body when you touch the strings/bridge/whammy bar. The only safety concern is to make sure that 1) the outlet you're using is properly grounded, and 2) the wiring/grounding on your equipment is good. If either is bad, it can 1) send RFI/EMI up the ground wire to your guitar, creating tons of noise, or 2) it can send live current up the ground wire to your bridge/strings, shocking you. D~s Quote
Devon Headen Posted November 24, 2004 Author Report Posted November 24, 2004 So it's actually being grounded to the output jack, not the bridge? Will I be ok if I don't connect ground to bridge? I'll probably wire it with ground to bridge, but I'm nearly positive that it will screw with my piezo signal. Quote
Paul Marossy Posted November 24, 2004 Report Posted November 24, 2004 I would recommend grounding the bridge. Not doing so presents a safety hazard to you. Read this: http://www.guitarnuts.com/technical/electr...afety/index.php Quote
lovekraft Posted November 24, 2004 Report Posted November 24, 2004 Ground the bridge - it won't have any effect on your piezo, since it's a microphonic sensor, and not a magnetic pickup. Quote
Devon Headen Posted November 24, 2004 Author Report Posted November 24, 2004 Thanks for the advice. I wired it up last night and this morning. Sure enough, I've got a grounding problem. Can't figure out exactly what's wrong, so I'm gonna have to dig around and figure it out. I got a signal from the piezo that sounded like junk. If I can't get a better sound than that from it I may scrap the whole idea and just go magnetic. Quote
lovekraft Posted November 25, 2004 Report Posted November 25, 2004 (edited) Try separating the two systems and debugging each one in turn. If they're already quiet separately, you've probably got a ground loop between the two systems. Try to make sure all your ground leads terminate at the same spot (that means pickup ground leads, bridge lead, shield leads, pot case connections, jack ground lead, and all piezo system ground leads). The back of the volume pot is traditional, but it doesn't matter, so long as everything grounded hooks up in one place. <edited for clarity (I hope)> Edited November 25, 2004 by lovekraft Quote
Devon Headen Posted November 25, 2004 Author Report Posted November 25, 2004 I thought I had the whole thing worked out. I'm about sick of taking the bridge off and on. I still have a problem, though. First off, somehow my piezo lead got connected to ground, so the whole thing was screwed. I just snipped the piezo lead trying to see if I could get the magnetic signal working. I still haven't been able to. I don't really understand what's going on, I've never had this much trouble before. When I touch the strings/bridge, or the pots, it's kind of a popping sound right when I touch it. Quote
Devon Headen Posted November 28, 2004 Author Report Posted November 28, 2004 Well, the piezo elements were somehow shorting my signal to ground, so tonight I just completely redid all the wiring minus the piezo. I got the piezo working before ripping it apart, but it sounded really bad. Maybe after I get this bad boy up and running I'll mess with trying the piezo again. I have everything working properly now, but I still have popping. When I touch the bridge or strings, it goes "pop", and then it goes back to normal. It's not loud, but none of my other guitars do it. I'm sure someone here can help . Quote
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