Posted by Daryl Bookout on August 30, 2009 at 4:16pm
I have a piezo wired to a 250k ohm pot & guitar jack. When I turn on the amp there's a loud hum/buz and I can't hear the strings thru the amp. If I curl my fingers around the guitar cable and touch the pot, the buzz goes away and the guitar plays thru the amp. Any ideas? If it is a ground issue, how do I fix it? I don't have a metal bridge...
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Great info, thanks for the help guys! This thing sounds good, looks great and was a lot of fun to build!! I'm hooked on CBG's now. Can't wait to take one up to our local blues jam and see how she acts in public. :)
Great info, thanks for the help guys! This thing sounds good, looks great and was a lot of fun to build!! I'm hooked on CBG's now. Can't wait to take one up to our local blues jam and see how she acts in public. :)
Great info, thanks for the help guys! This thing sounds good, looks great and was a lot of fun to build!! I'm hooked on CBG's now. Can't wait to take one up to our local blues jam and see how she acts in public. :)
Ted Crocker said:
What I do is solder a stripped length of solid core wire from the ground lug to the back of the pot and then solder all of the ground wires to that wire, including just one that goes to the ground on the jack. This way you apply the least amount of heat to the pot which could cause damage.
Daryl, from your pic it looked like you may have a stereo jack, maybe the original ground wire you soldered went to the wrong tab...
Also, I wire mine like the diagram that Wes posted, it looks like you reversed the wires on the outside lugs of the pot.
Ted, I actually wired mine based on _your_ diagram using the minty Amp :-) So I guess it comes full circle eh?
-Wes
Ted Crocker said:
What I do is solder a stripped length of solid core wire from the ground lug to the back of the pot and then solder all of the ground wires to that wire, including just one that goes to the ground on the jack. This way you apply the least amount of heat to the pot which could cause damage.
Daryl, from your pic it looked like you may have a stereo jack, maybe the original ground wire you soldered went to the wrong tab...
Also, I wire mine like the diagram that Wes posted, it looks like you reversed the wires on the outside lugs of the pot.
Si, or bend the put lug back and solder that to the body if yer able. I hate to say it, I had mine wired exactly as shown -- that is three wires to the third lug. Black from the Piezo, one to the body of the pot and one to the ring lug. Too many wires IMHO.
-Wes
Daryl Bookout said:
Thanks Wes, problem solved!! I ran a wire from the back of the pot to the 3rd lug on the jack and it all works great now - no hum, smooth tone! Question... I was wired as per your diagram and still had the hum (solved by touching the pot and the metal jacket on the guitar cable). When I wired from the pot to the jack, problem went away... When you guys say "ground the pot" do you mean running a wire to the 3rd lug as I did?
Si, or bend the put lug back and solder that to the body if yer able. I hate to say it, I had mine wired exactly as shown -- that is three wires to the third lug. Black from the Piezo, one to the body of the pot and one to the ring lug. Too many wires IMHO.
-Wes
Daryl Bookout said:
Thanks Wes, problem solved!! I ran a wire from the back of the pot to the 3rd lug on the jack and it all works great now - no hum, smooth tone! Question... I was wired as per your diagram and still had the hum (solved by touching the pot and the metal jacket on the guitar cable). When I wired from the pot to the jack, problem went away... When you guys say "ground the pot" do you mean running a wire to the 3rd lug as I did?
Thanks Wes, problem solved!! I ran a wire from the back of the pot to the 3rd lug on the jack and it all works great now - no hum, smooth tone!
Question... I was wired as per your diagram and still had the hum (solved by touching the pot and the metal jacket on the guitar cable). When I wired from the pot to the jack, problem went away... When you guys say "ground the pot" do you mean running a wire to the 3rd lug as I did?
If your are not using a metal bridge, are you running your strings through rivets at the tailpiece? If so you can ground the rivets with a common wire.
As well, what kind of wire are you using? Try RGU-74 coax shielded, it helps most buzzes.
The wiring diag I follow in on my page here. It has a vol and tone pot and a capacitor which helps noise.
Replies
Tres Seaver said:
Cool -- post photos / recording / video, please!
Ted Crocker said:
-Wes
Ted Crocker said:
Wes Yates said:
-Wes
Daryl Bookout said:
Question... I was wired as per your diagram and still had the hum (solved by touching the pot and the metal jacket on the guitar cable). When I wired from the pot to the jack, problem went away... When you guys say "ground the pot" do you mean running a wire to the 3rd lug as I did?
PiezoWireing.pdf
Daryl Bookout said:
As well, what kind of wire are you using? Try RGU-74 coax shielded, it helps most buzzes.
The wiring diag I follow in on my page here. It has a vol and tone pot and a capacitor which helps noise.
Let me know how things work out.
Mike
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