Help! Humbucker is Humming

Clyde Willis · Post by **Clyde Willis** » 14 Jun 2002 2:06 pm

I am trying to install an EMG "Select" humbucker in a lap steel I'm building, using the schematic that came with the pickup, but I get this heavy 60 hz hum when I plug it in the amp. Hum vanishes when I touch the cord plug, but if touch the bare tone or volume pot shafts, the hum comes back in a big way.
I'm sure its something simple, but I'm fresh out of ideas. Any advice would be most welcome as I have been working on the this guitar for a good while and I would really like to get it finished and see what it sounds like (minus the hum).
Thanks CW

Tim Rowley · Post by **Tim Rowley** » 15 Jun 2002 9:59 pm

Sounds to me as though you have the leads reversed. White should be "hot" and go to the tip terminal of the 1/4" jack, black is the neutral and goes to the sleeve terminal. Opposite of house wiring. See if maybe they need to be switched around.

Tim R.

Post by **Brad Bechtel** » 16 Jun 2002 8:05 am

Let's move this to the Electronics forum from No Peddlers. Perhaps more people will respond with suggestions.

Dave Boothroyd · Post by **Dave Boothroyd** » 17 Jun 2002 1:08 am

Could be an earth loop - or are you trying this in the same room as your PC is running?
Try adding a Bonding wire- a thick copper (say 1.5mm) wire that connects everything that is meant to be grounded, in the shortest way possible. That's Black on your pickup, the bodies of your controls, the sleeve connection on the output jack, the foil screening that you put in the routed hole that the controls fit into. If you have any metalwork on the guitar that you touch when you are playing - the bridge for example, you might include that too.
Is there a centre tap on your pickup?- normally a Humbucker is actually two coils, wired in opposite phase, so that by combining the signals the hum is cancelled.
Are you sure you are not just using half of it?
Cheers
Dave

Clyde Willis · Post by **Clyde Willis** » 17 Jun 2002 5:09 am

Tim you were right; I had the leads to the jack reversed. Many thanks to you and Dave for your help!
CW