Wiring Help! - Telecaster Guitar Forum
The Number 1 Fender Telecaster Guitar authority in the world.
   

Go Back   Telecaster Guitar Forum > Main Telecaster Forum > Tele-Technical
Forgot Username/Password? Join Us!
Notices

Tele-Technical Telecaster nuts and bolts talk ONLY


Wilde Pickups by Bill & Becky Lawrence WD Music Products Amplified Parts Mod Kits DIY Amps, Mods, Pedals dallenpickups.com Warmoth.com seymourduncan.com


Forum Jump


Reply
 
Thread Tools
Old February 16th, 2012, 01:12 AM   #1 (permalink)
Tele-Meister
 
Trow's Avatar
 
Join Date: Jan 2010
Location: San Antonio/Fort Worth
Posts: 436
Wiring Help!

I'm not sure if this is the place for this. If it isn't I'm sorry mods!
On to the question. I have an Epi Lp Jr that I recently got a p90 for. I routed and got it all soldered up but there is an incredible hum. I understand it is a p90 and they do that, but this hum is louder than the pickup. I tried re-shielding, checking my grounds. And then finally touching various parts. Touching the bridge does nothing. Touching the strings makes the hum louder. But, touching the input jack reduces the hum considerably. I am using a two pronged switchcraft styled jack. Do I ground the + or the -? Also, should I ground it to the casing on the volume pot? Is there anything else I should ground while I'm in there? Thanks!

__________________
I don't suffer from insanity. I enjoy every minute of it!

The fame don't take away the pain it just pays the bills, and you wind up on alcohol and pills.
Trow is offline   Reply With Quote

Old February 16th, 2012, 08:21 AM   #2 (permalink)
Poster Extraordinaire
 
sjtalon's Avatar
 
Join Date: Oct 2006
Location: Upper Peninsula of Michigan
Age: 55
Posts: 8,006
The - side of things needs to be to ground. The sleeve contact part of the jack should be to ground, and the tip of the jack needs to be the positive (hot).

There should be a wire that runs from one of the bridge post screws to the back of a pot to ground the strings.

Either volume or tone pot can have grounds to them and they should all have a wire on their backs tiring them all together electrically. Unless the pots are mounted in a metal plate that is, as that would connect them all together as well.

http://www.mylespaul.com/forums/memb...ringmodern.jpg
sjtalon is offline   Reply With Quote

Old February 16th, 2012, 01:10 PM   #3 (permalink)
Tele-Afflicted
 
tfsails's Avatar
 
Join Date: Oct 2010
Location: Richmond VA
Posts: 1,807
Everything metal on that guitar needs to be electrically connected to ground. You should be able to take one lead of an ohmmeter and touch the ground side of the jack (or the barrel of a guitar cord that's plugged into the guitar) and any metal part of the guitar and get less than 10Ω of resistance. If you get more from anything, you have a grounding problem. Fix that problem and you'll likely fix your hum.
tfsails is offline   Reply With Quote

Sponsored Links   #
Sponsored posting
 

Old February 16th, 2012, 04:30 PM   #4 (permalink)
Tele-Meister
 
Trow's Avatar
 
Join Date: Jan 2010
Location: San Antonio/Fort Worth
Posts: 436
Thanks y'all! I already connected the ground to bridge. I guess tonight after work I'll just grounding anything metal haha. I'll let you guys know how she turns out.
__________________
I don't suffer from insanity. I enjoy every minute of it!

The fame don't take away the pain it just pays the bills, and you wind up on alcohol and pills.
Trow is offline   Reply With Quote

Old February 18th, 2012, 02:09 AM   #5 (permalink)
Tele-Meister
 
Trow's Avatar
 
Join Date: Jan 2010
Location: San Antonio/Fort Worth
Posts: 436
Update!
So I grounded the - of the input jack, and I grounded the two pots and the only thing that changed was now the hum increases whenever I touch anything metal: strings, bridge, even the tuning pegs. So... any idea whats wrong?
__________________
I don't suffer from insanity. I enjoy every minute of it!

The fame don't take away the pain it just pays the bills, and you wind up on alcohol and pills.
Trow is offline   Reply With Quote

Old February 18th, 2012, 10:23 AM   #6 (permalink)
Poster Extraordinaire
 
sjtalon's Avatar
 
Join Date: Oct 2006
Location: Upper Peninsula of Michigan
Age: 55
Posts: 8,006
Sounds like you have a positive wire touching ground somewhere.

So to the OUTPUT jack, you should only have two wires, one from the middle toggle switch terminals goes to the tip, and the one from the back of a pot goes to sleeve.

Verify continuity with all that. And when you test the + side of the jack (the tab that contacts your cable jack tip), you should only get your pickup resistance readings of 7-10 KΩ depending if you are in selector switch position T or R.

Not to confuse but check this out and look at how the pots, jack and switch are wired. You most likely have one pickup + wire to each vol. pot, one ground wire from each pup to the back of a pot.

Disregard how the caps on the tone pot are wired from cap to pot in this diagram as there are different ways that can be done. They are also wired, commonly on Gibson/Epiphone, from tone pot to vol. pot.

http://www.seymourduncan.com/support...ic=2h_2v_2t_3w

Are you sure the new P90 is good ?? The problem happened when you installed that right ?
sjtalon is offline   Reply With Quote

Old February 18th, 2012, 10:34 AM   #7 (permalink)
Tele-Afflicted
 
tfsails's Avatar
 
Join Date: Oct 2010
Location: Richmond VA
Posts: 1,807
Quote:
Originally Posted by Trow View Post
Update!
So I grounded the - of the input jack, and I grounded the two pots and the only thing that changed was now the hum increases whenever I touch anything metal: strings, bridge, even the tuning pegs. So... any idea whats wrong?
Let me explain "grounding". If you already know this, I apologize for sounding condescending.

"Ground" in electronics is the return path for electricity to flow. Electricity won't flow if it cannot complete a circuit. A switch, for instance, opens the circuit and electricity won't flow through that circuit until the switch is closed again. "Ground" gets its name from the earth, to which all electricity eventually flows.

You should be able to plug your guitar into your amp and read < 10 ohms of resistance from any metal part of the guitar to the ground prong on the amp's power plug. If you can get this reading, your guitar should be properly grounded. If you do get this reading and you still have the noise problem, try plugging your amp into a different socket in the house to see if the problem goes away. If it does, then you have a problem with the ground wiring on the first plug. If the noise doesn't go away, take the whole setup to another house or building and plug it in there and try it. If the noise goes away your house has a ground problem.

Be very careful if you find your house has a grounding problem. Improper grounding of electronic things that require a good ground can kill you if you touch the wrong thing at the wrong time. An example: touching your guitar strings while plugged into an amp and touching a microphone that's plugged into a PA system with your lips. Your body is the link between those two ungrounded circuits and if the voltage potential is high enough, you get zapped. Or killed.

If your house has a grounding problem, you need to get a qualified electrician to fix it ASAP. Don't plug your guitar amp into an ungrounded system. If you were to touch anything electric while touching the guitar, you might be electrocuted.

You can get an inexpensive tester to check home wiring at any Home Depot or Lowe's. Cheap insurance.

Now, on to your guitar's ground circuit: The "-" side of the jack is where all grounds inside your guitar run to, electrically speaking. All those black wires that congregate on the back of the pots are the grounds from all pups, the bridge, and anything else that needs a ground. Then one wire runs from the pots to the negative side of the jack. That side of the jack makes electrical contact with the barrel of the input cable; the other end's barrel makes electrical contact with the amplifier's ground circuit and out it goes to the power plug and eventually to earth through the house wiring. If you have all of these conditions, you have a properly grounded guitar. At this point touching the strings should have no effect on any humming or static noise.

Some hum comes from the pups. If you have humbuckers that hum should be minimized. Single coils like most found on Fenders are more susceptible to hum and there's not a lot you can do about that. This hum will not change by touching or letting go of the strings.
tfsails is offline   Reply With Quote

Old March 10th, 2012, 06:12 AM   #8 (permalink)
Tele-Meister
 
Bubbalou's Avatar
 
Join Date: Feb 2012
Location: Euless, Texas
Posts: 279
It sounds like you have the signal and ground to the output jack swapped.
__________________
I owe my life to Jesus
Bubbalou is offline   Reply With Quote

Reply

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


» Random Photo for Guests
Smith Custom T in Green flake
Untitled Document



 


Powered by vBadvanced CMPS v3.2.2



IMPORTANT:Treat everyone here with respect, no matter how difficult! No sex, drug, political, religion or hate discussion permitted here.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0 RC 2
© TDPRI.COM 1999 - 2014 All rights reserved.