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ground issue on guitar

Posted: Fri Mar 21, 2014 5:41 pm
by the Life Aquatic
So I get a lot of noise coming from my guitar. My amp will be cranked and silent then I plug in my guitar and boom, hiss. IVe changed cables and the amp is the only thing plugged into the power conditioner so I am positive the guitar is soley the issue.

When I touch the strings or bridge the hiss backs off a bit.

Ive checked for continuity between all ground connections and they all seem fine.

Cant find any places where there's a short or solder bridge that breaks the connection to ground or something.

Anyone got any advice or can solve my issue? I will take the strings off and pull the pups out too see if maybe there's something shorting there?

This is driving me insane. and I don't want to/cant afford to take it to a tech to fix something that I know will be an easy fix or I missed.

Help. Where Should I check/look next.

Re: ground issue on guitar

Posted: Sat Mar 22, 2014 12:53 am
by Nelson Instruments
Single coil pickups?

Re: ground issue on guitar

Posted: Sat Mar 22, 2014 12:58 am
by AxAxSxS
bridge ground wire.

Re: ground issue on guitar

Posted: Sat Mar 22, 2014 3:01 am
by the Life Aquatic
AxAxSxS wrote:bridge ground wire.


Can you elaborate on this? There's continuity between the wire going from the bridge to the ring of the out put jack and every other ground connection.

Also they're p90s. I know single coils and p90s arent as silent as humbuckers but the noise level shouldnt change when I touch the strings and bridge and it shouldnt be this unbearable with any amount of gain.

Re: ground issue on guitar

Posted: Sat Mar 22, 2014 10:52 pm
by Decibill
Try reflowing the solder joints. Also, make sure there is only one path to ground. I've seen guitars where they are grounded to the pickup cavity, the output jack and the bridge, which can definitely make for grounding issues.

Re: ground issue on guitar

Posted: Sat Mar 22, 2014 11:14 pm
by AxAxSxS
the Life Aquatic wrote:
AxAxSxS wrote:bridge ground wire.


Can you elaborate on this? There's continuity between the wire going from the bridge to the ring of the out put jack and every other ground connection.

Also they're p90s. I know single coils and p90s arent as silent as humbuckers but the noise level shouldnt change when I touch the strings and bridge and it shouldnt be this unbearable with any amount of gain.


What decibel said. I am assuming you have a multimeter since you have checked continuity. can you check from the strings? Normally when there is hum that cuts out when you touch the strings, it is because you are becoming the ground. that indicates either no ground or an issue with the ground path. definitely flow the connections. It is possible to have a weak join.

I think knowing what the guitar in question is and how it is wired would help people be more helpful.

Re: ground issue on guitar

Posted: Sun Mar 23, 2014 1:27 pm
by the Life Aquatic
Decibill wrote:Try reflowing the solder joints. Also, make sure there is only one path to ground. I've seen guitars where they are grounded to the pickup cavity, the output jack and the bridge, which can definitely make for grounding issues.


Only path to ground is bridge and output jack. Wired up exactly as this wiring diagram.
http://www.seymourduncan.com/images/pro ... 25-100.pdf

Re: ground issue on guitar

Posted: Sun Mar 23, 2014 11:11 pm
by Decibill
What happens when you disconnect the bridge ground...? Better or worse....?

Re: ground issue on guitar

Posted: Mon Mar 24, 2014 7:45 am
by the Life Aquatic
Decibill wrote:What happens when you disconnect the bridge ground...? Better or worse....?


Havent tried that. I'll give it a shot later today.

Re: ground issue on guitar

Posted: Tue Mar 25, 2014 2:17 am
by dub
If touching the strings grounds some of the noise, then your bridge wire is fine. Otherwise you wouldn't be brought into the circuit at all.

Re: ground issue on guitar

Posted: Tue Mar 25, 2014 3:08 am
by AxAxSxS
dub wrote:If touching the strings grounds some of the noise, then your bridge wire is fine. Otherwise you wouldn't be brought into the circuit at all.

Am I fucked up on this? Not trying to be an ass, I really want to know. I always figured a body ground killing hum was indicative of something not being connected. I tend to shotgun blast fixes and just tear out everything when somethings fucked and do it ALL over. so many guitars have shitty parts in them and once i get in there it's kinda a "why not fix it all" thing for me. But shit if I am wasting time please elaborate and school us a bit.

Re: ground issue on guitar

Posted: Tue Mar 25, 2014 3:30 am
by dub
Yeah, something is definitely not connected, and I don't know jack about electronics. But since the strings would only be part of the circuit because of the bridge wire, seems like it's there.

I've been having a similar thing with ALL my guitars recently, the amount of extra noise depends on how well they're grounded/shielded, my yamaha, it's barely noticable, the p90s SG it's louder (although today I tightened output jack, and couldn't hear it at all-so maybe it was that). It also persisted between different amps. So for me, it might exacerbated by the power in my house, what else is plugged into the circuit/lay-lines/who the fuck knows.

Re: ground issue on guitar

Posted: Tue Mar 25, 2014 3:49 am
by AxAxSxS
dub wrote:Yeah, something is definitely not connected, and I don't know jack about electronics. But since the strings would only be part of the circuit because of the bridge wire, seems like it's there.

I've been having a similar thing with ALL my guitars recently, the amount of extra noise depends on how well they're grounded/shielded, my yamaha, it's barely noticable, the p90s SG it's louder (although today I tightened output jack, and couldn't hear it at all-so maybe it was that). It also persisted between different amps. So for me, it might exacerbated by the power in my house, what else is plugged into the circuit/lay-lines/who the fuck knows.


I hear ya man. I have horrible power in the house with old knob and tube style wiring, no grounds. el shitto. I believe anything that can conduct elec can become a ground though. as in a human. Its easy to become part of a circuit, ask anyone who has gotten bit by an amp or microphone in a shitty venue. power wants to flow, if the correct path is not available, it will find an alternate path, or sound like shit, fuck man, two shows ago i was getting my teeth electrocuted every time I went to the mic. not pleasant. I'm not supposed to be a part of the circuit so when I am I assume something is borked.