LOUD guitar hum after pickup change.

[doulos30]

did you line the cavity with shielding?

[Richard Crowley]

Is the ground/shield connected properly at all points? Your symptoms are classic for broken ground connection.

[a.smith]

Hi again,

Thanks for replying. The underside of the pick guard where the two tone and volume knobs are has a foil-like sticker under there, is that what the shield is?

And, I do assume that it has something to do with grounding. The black wire which goes from the volume pot, through the guitar to be soldered onto the spring holder thing is back the same way it was before it was humming, so I'm a little bit confused. Perhaps it would be of help if I took some pictures and posted them here?

Thanks a lot for taking the time.

[Richard Crowley]

I am pretty sure that if there is a metalic surface (the foil sticker), it is intended as a shield and should be grounded. But there may be a metalic case around the pickup and that should probably also be grounded. And the shell (not the terminals) of the pots and switches. And the outside part of any connectors, etc, etc.

It is a tricky thing, to get such a sensitive circuit shielded properly when it is contained in a non-metalic enclosure (the guitar body). That is why you see things like the foil stickers, etc. to attempt to shield the more sensitive parts.

[SAnthony]

I am assuming you took the guitar down to the body and removed the electronics. Did you replace the ground wire going to the bridge "Claw"?
This should be soldered back to the grounds on the back of the Pots.
That alone will give you a terrible hum. also, you need to check the wiring on the center pickup. If your other ground wires are soldered properly, your new pickups may be wound in the opposite direction of your stock pickups.
Try swapping the 2 wires on your center pickup. If this is the case you will notice it is considerably quieter in positions 2 and 4 (assuming this is a 5 position switch). Also check the wiring from the input jack.... make sure the tip of the input jack goes to your switch and the sleve is going to your grounds on the back of the Pots. I hope this helps....
Good Luck,
Shawn

[fireberd]

Add poor/cold solder joint to the list of possibilites.

Another potential is the replacement Pickups. Are they "known good" pickups?

Although a hassle, you could reinstall the original pickups and see if you still get the hum or if its gone.

[a.smith]

So, to recap what I've tried/have done:
-positions 2 and 4 on the switch are perfectly fine, no abnormal fuzz or hum. --

-The black ground wire is soldered to the volume pot and sent through the guitar to the spring "claw".

-Each pickup has one wire going to the selector and another going to the volume pot (I've already tried to reverse the wires the opposite way, yielding the same results).

-And although my soldering job is par at best, I can say i did a better job than how it was originally soldered.(although, it is humming obviously).

-To answer your question fireberd, I bought the pickups from a friend who wouldn't screw me over and I tried them on the guitar before he took them out. But, it is a valid question since there are people who do that kind of thing all the time.

-I also rewired the pickup jack because it was getting pretty loose, so that is in there perfectly as well.

Santhony, what you said about the pickups being wound the opposite direction sounds intriguing, the back of authentic strat pickups have like a pointy side where the wires are(if you know what I mean) which are meant to point toward the bridge, however, the stock pickups on the other hand, were all pointing toward the neck. So I'm thinking this could be the issue.

Also, there are two wires that connect to the input jack, would it matter if they were soldered the opposite way? Or is it the same either way?

Thanks for all the help e'erone!

[fireberd]

Have a look at this wiring diagram.

Google Image Result for http://www.legendarytones.com/Strat.JPG

[a.smith]

Ohhh! So, is it essential for the pickup ground wires to be soldered to the same spot so every pickup ground is touching one another?

Because at the moment right now, they are all soldered to the volume pot, but not necessarily touching one another.

[Richard Crowley]

Not clear what you mean by "soldered..but not necessarily touching". Electrical connections are absolutely mandatory. But physical touching is of no particular benefit. In some cases the exact order of what is connected where is critical to the performance of the shield circuit. Restoring all the the original shield/ground connections exactly should be a very high priority. Expecially when experiencing hum problems. Shielding and grounding has a significant "black-magic" factor beyond simple circuit topology.

[SAnthony]

The Polarity on your input Jack Definately matters. The Sleve should only be soldered to Ground and the Tip Only to switch. Reversing these will bring on a terrible hum...no question about it.
S.

[a.smith]

A little bit of an update, in case anyone is wondering.

The problem has been solved, it turned out that the ground wires from each pickup needed to be twisted together in an orderly fashion and then soldered to the volume pot.

Thanks for all the help, it is much appreciated.