Petrucci grounding/earthing problem

[eliot323]

Hi there
Help needed please! I've got a JP6 original (not D-Sonic PUP) with Piezo that is humming like a beehive.

The hum disappears when I touch the strings and thus it sounds like a grounding (earthing as we Europeans call it) problem. I've checked all the soldering and all the wires which are intact; the bridge claw solder is fine as is the output plug.

I've taken the wire from the ground lug screw and tried to get in contact with the back of the cavity cover - this helps a bit but not much. If I try to attach the wire to the volume or tone pot I can get rid of the hum but only at the expense of the sound or tone control respectively.

My other 2 D-Sonics are fine - there's just the usual amp hum, its only this one that is causing me problems. Can anybody help?

 

[Philip]

strange. Mine also was humming when I wasn't touching the strings but it is totally normal. It means that it is grounded good. But if your D-sonics ones don't do it so I am a little confused...

I might suggest to contact a EB customer service first than posting here

 

[SteveB]

eliot,

Is the hum coming from your magnetic pickups or your piezo? If you're getting hum from the piezo, I'd suggest connecting the piezo output to a DI box with a ground lift switch to resolve the hum.

Otherwise, I'd try a few other things. First, I'd make sure all my gear is plugged into the same circuit so that they share a common ground. Then, I'd try a few different electrical outlets to see if the wiring is the problem. Then I would check inside the guitar to ensure that the ground wire hasn't been disconnected.

 

[eliot323]

Hi Steve
Thanks for this - the hum is coming from the magnetic pickups and I shall check the other things you mention - all of the guitar's internal wiring is intact.

Currently (no pun intended), the effects are being powered from a separate socket to the amps, which I will assess.

The odd thing is that both the D-Sonics are fine...maybe the original pups have different characteristics (although I can't say that they sound very different).

 

[chrisallen]

there's a "paper clip" looking wire wedged under the pot cover on the back... is that still there? and is the ground wire still attached to the trem claw?

 

[phatduckk]

i had a similar issue with my beater bass that i modded w/ a new preamp (non MM bass - first bass ever). i also thought it was a grounding issue with the bass cuz i had the same symptoms you have. so i called my dad to help cuz he knows all about electronics (hes been doing electronics stuff for 30+ years) and he checked it out and said the bass was fine but it had something to do with my cottage's electrical causing the amp to get mad. he then grounded my amp and voila, the buzz was gone

i aksed why it happened with just this one bass and not any of the others and he sketched some super complicated drawing & graph thing that ill never understand.

so i guess what im saying is that from my experience its possible for the electronics in a particular guitar to bring to light a power issue that could have otherwise gone unnoticed.

turns out he was right tho cuz the same amp & same bass produced no hum when i took 'em to a jam session at a friend's house.

 

[eliot323]

Hi guys
Thanks for this - I will check your suggestions out. It's not a big deal and if I can't solve it, I'll just have to learn to use the volume control properly.