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Thunderbird Club

#14,381
Hey Everybody!
so this may have been covered a few times, but searching mostly brought up threads that went no where.

I have an Epi Thunderbird pro IV, trans-black finish, pretty slick looking. it has a terrible buzz in the electronics. the buzz would stop if I touched metal (the strings, one of the knobs, etc.), so grounding issue somewhere.

I went through and shielded all the cavities with copper tape (the only thing I couldn't do at the time was ground the neck pup cavity as I only had solid core wire and couldn't get past the 90 degree angle in the wire tunnel.) I also added the tape in a strip under the bridge with the bridge ground wire sandwiched between 2 pieces, and the tape on the body where the screws enter for the most contact.

put it all back together, ground the main cavity to the volume pot, and now touching the strings/bridge/tuners has no effect on the buzz, its always there now, unless I am touching/turning the blend/pup selector pot, then the buzz goes away intermittently. I experimented in trying to ground the pot better (thinking it would help), but it has had no effect. when taking the cavity apart to shield it, I noticed this was the only pot with 2 locking washers instead of 1 regular washer on it like all the others (doubt that was anything to do with it, but noticed it none the less).

*edit to add*- the buzz is not just on the neck pup side of the blend pot where the cavity has not been connected to ground, its across the entire travel for the pot, bridge / bridge & neck / neck.

anyone have a similar experience or can comment on the noisy electronics? I've considered going passive with it, so if anyone has anything to say about that I would love to hear what you did and how it sounded afterward. generally I prefer passive basses, and I don't really use the pre-amp in this one, so I would be ok with taking it out, but id like to talk to someone before I throw money at a nice passive electronics set up.

thanks!
 
Last edited:
#14,383
Gaolee said:
Is all the wiring solidly soldered? A bad ground is all I can think of, or maybe you have an inadvertent coil tap somehow. It's all I can think of. Every 'Bird I own is nearly silent until you want it to make noise. Then it makes lots of noise.
Click to expand...

I tugged on all the wires while I was in there and nothing seemed amiss, but that's not to say it isn't somewhere.

Im not sure if it's a coil tap thing, the pups have an extra red wire each that I've been told are for that very purpose, and they aren't hooked up to anything.
 
#14,386
Gaolee said:
I'll try to remember to hunt down a schematic or look inside of my Epi 'Bird. No, those shouldn't be just dangling.
Click to expand...

It would be much appreciated and helpful.

I did find another thread where the person thought those wires were supposed to be hooked up to the battery, he thought the pups themselves were active (I don't think they are). When they did this, the blend knob would produce a "scratching" noise when being turned, it was later explained that was wrong. And then when sending them to ground it was shorting one of the coils in each pup. At least that's how I understood it.

They also had a few other "fixes", none of which actually did anything.
 
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#14,390
Sahe_Bassist said:
Hey Everybody!
so this may have been covered a few times, but searching mostly brought up threads that went no where.

I have an Epi Thunderbird pro IV, trans-black finish, pretty slick looking. it has a terrible buzz in the electronics. the buzz would stop if I touched metal (the strings, one of the knobs, etc.), so grounding issue somewhere.

I went through and shielded all the cavities with copper tape (the only thing I couldn't do at the time was ground the neck pup cavity as I only had solid core wire and couldn't get past the 90 degree angle in the wire tunnel.) I also added the tape in a strip under the bridge with the bridge ground wire sandwiched between 2 pieces, and the tape on the body where the screws enter for the most contact.

put it all back together, ground the main cavity to the volume pot, and now touching the strings/bridge/tuners has no effect on the buzz, its always there now, unless I am touching/turning the blend/pup selector pot, then the buzz goes away intermittently. I experimented in trying to ground the pot better (thinking it would help), but it has had no effect. when taking the cavity apart to shield it, I noticed this was the only pot with 2 locking washers instead of 1 regular washer on it like all the others (doubt that was anything to do with it, but noticed it none the less).

*edit to add*- the buzz is not just on the neck pup side of the blend pot where the cavity has not been connected to ground, its across the entire travel for the pot, bridge / bridge & neck / neck.

anyone have a similar experience or can comment on the noisy electronics? I've considered going passive with it, so if anyone has anything to say about that I would love to hear what you did and how it sounded afterward. generally I prefer passive basses, and I don't really use the pre-amp in this one, so I would be ok with taking it out, but id like to talk to someone before I throw money at a nice passive electronics set up.

thanks!
Click to expand...
Yes! My Epi ProIV was unplayable when I first got it. I sent it to a tech that had to order something that took forever, as shielding did not help. PM me and I will give you contact info to the Ken Stanton Store.
 

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