Wiring hummmmmmmmm

1stpitch

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Yeah, I can't really see the bottom very well, and I am not well-versed on concentric pots. Does each case require a separate ground, or are they jumped internally?
Been a while since I looked at the datasheet, but pretty sure they are 2 separate pots. I might have one in the parts drawer and could measure it later, but someone should know.

Edit: I didn't have a concentric pot to measure except in a guitar. The CTS datasheet shows the circuit for the resistor circuits but not anything else. I do remember the last time I put some in, I soldered a separate ground to the side of the cases of the bottom pots.
 
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Telenator

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Just strip it all out and start again. This is not a complicated project.
Wire it exactly exactly as the diagram shows, and run a single wire from the ground on the output jack to the bridge.
If that doesn't work, bring it somewhere and get it fix. Then you'll learn what went wrong.
This is not a two page problem.
 

pipthepilot

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Hi Grant,

The fact that the hum stops when you touch the bridge, or other metals parts, means your ground is fine. Many of the posts above are focusing on grounding the bridge but based on your description, this is not the issue!

My opinion, your wiring is overly complicated and have more wires than you need. The more wires you have, the more possibility for interference.

It's hard to match the circuit diagram, you posted earlier, to your photos but I can see your pickups are 4 wire and not vintage style single/shielded. With 4 wires, there is possibility they are wired in such as way that the coils are not cancelling hum. The photo suggests that the Red & White wires are the link wires, Black is hot and green is GND. If these are Seymour Duncan then that is correct but there is no standard wire colour, different manufacturers use different colours. Suggest you check.

I created the diagram below to help you simplify your wiring. The upper concentric pot is the Volume for both pickups, the lower concentric pot is the tone for both pickup. The diagram also assumes that both pots and bridge are grounded together via the copper shielding tape on your pickguard. You can add an additional wire between the pots and pot to bridge if you want, I never do and never had any issues but make sure you test GND connectivity with a multimeter. I've assumed SD wire colours for PUs.

HH-3W-V-T.png

Hope this is useful?
 

Telenator

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Hi Grant,

The fact that the hum stops when you touch the bridge, or other metals parts, means your ground is fine. Many of the posts above are focusing on grounding the bridge but based on your description, this is not the issue!

View attachment 1054980

Hope this is useful?
The hum does not stop when he touches the bridge. That's why it has been suggested he run a ground wire to the bridge, in an effort to make the hum stop when he's holding the strings or touching the guitar. The vast majority of electric guitars out there hava a ground lead running to the bridge. A From what I've seen, Grant's does not.
Time to just hack the wiring our and simplify. Start over.
 

pipthepilot

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The hum does not stop when he touches the bridge. That's why it has been suggested he run a ground wire to the bridge, in an effort to make the hum stop when he's holding the strings or touching the guitar. The vast majority of electric guitars out there hava a ground lead running to the bridge. A From what I've seen, Grant's does not.
Time to just hack the wiring our and simplify. Start over.

Hi, in the very first post he said "The humming drops away if I touch the pickups, pots shielding or bridge." He repeated this in his second post saying all ground leads attach to the pot, again mentioning the Bridge. He also mention the same in his third post saying "I've currently got a ground wire from the bridge to the back of a pot".

This is why I'm pretty sure the GND to bridge wire is not the issue.
 
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Telenator

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Hi, in the very first post he said "The humming drops away if I touch the pickups, pots shielding or bridge." He repeated this in his second post saying all ground leads attach to the pot, again mentioning the Bridge. He also mention the same in his third post saying "I've currently got a ground wire from the bridge to the back of a pot".

This is why I'm pretty sure the GND to bridge wire is not the issue.
My apologies. You're right.
 

Lostininverness

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Hi all, sorry, been tied up of late - live getting in the way and all that! But thanks to everyone for the advice. I removed one of the jumpers I put in joining the grounds between the vol/tone parts of the pot and reflowed some solder on the grounds. Not sure what it was, but seemed to have taken care of the issue. Now we are humming but in a rock and roll way!

Thought I'd include a pic of the finished guitar.

IMG_2321.jpg IMG_2322.jpg IMG_2323.jpg IMG_2327.jpg IMG_2333.jpg

Again, thanks for the advice, this is a great place!

Cheers Grant
 




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