grounded?

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zmartin66
Posts: 6
Joined: Wed Mar 13, 2013 2:49 pm

grounded?

Post by zmartin66 »

Hi all,

I hope it’s OK that I am posting this here instead of in the electronics section. Just seems like this is more a beginner issue with electronics than a real electronics post might be. But anyway…

I am having a lot of issues with buzz and have been pretty thorough with trouble shooting and reducing the cause to one of two things:

1) my pup is a lemon, or 2) for reasons I don’t understand my ground wire is not making proper connection with the bridge.

I have played guitar for years and am familiar with noisy single coil pickups, but unless I am really mistaken, the buzz I am getting is not a matter of shielding (which I did). This is the first time I have done something like this so it’s not impossible that the issue is with my soldering joints, but I have been pretty methodical with soldering and stuck as best I can to what I understand to be standard best practices (no blowing on joints, pre tinning, cleaning the tip, pre tin again, and so on). Assuming I am correct about this, I went on with eliminating other possible causes by shortening the path bit by bit until I had the pickup going straight to the jack. When I was still getting a lot of noise at this point, just for curiosity sake, I decided to remove the ground wire to the bridge just to see if the noise changed in anyway and lo and behold, it did not. Thus I have come to think it is one of the two above stated issues.

My question is this, based on the picture here, can anyone think of why my ground wire would not be making sufficient contact with the bridge (not pictured, but when everything is assembled, the bridge sits right on top of the wire that I soldered to a small strip of copper foil) ?

The pickup is one of those Gretsch Electro Lap Steel Pickups that I got via Amazon for about $25.00. I don’t have another pickup to test out at the moment so can’t confirm there is any issue with this one, and before I go out and buy another one I want to be as sure as I can the fault lies here. On a somewhat different note though, Other than the buzz, the pickup actually has a nice warm tone, albeit lacking a little in the gain department when I want something nastier, but of course a simple stomp box would solve this issue.

So all that said, I would love to know what people think about this problem. I have never done any of this type of work before so am really unsure what else there is to try to locate the source of this problem.

Thanks!
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Jif
Posts: 86
Joined: Thu Nov 08, 2012 12:54 pm
Location: Scotland

Re: grounded?

Post by Jif »

Hi I posted this in the introductions section before you posted this here. I've copied and pasted from there to here -

I used to be an electronics tech. / engineer, the basic method of fault finding a circuit is to cut the problem in half, see what half the problem remains in, cut that in half etc until you pinpoint the cause of the problem.

I would connect the P/UP straight onto the jack, if you are still getting hum then it's probably related to the pickup. If not then it's getting in through the pots or the wiring around the pots. Try and have all your ground wires soldered onto a single spot, i.e. star wiring, usually onto the metal case of one of the pots. Both pot cases should be grounded.

Dry solder joints can also give you hum problems, always pre-solder any wires and surfaces before you solder the joint. When soldering the joint, feed the solder into the joint so that you are getting plenty of flux in to make the solder flow correctly. As soon as the solder flows nicely, remove the iron, it only takes a couple of seconds to flow if the wires etc have been pre-soldered. If you leave the heat on too long, you risk a dry joint.

Before pre-soldering the pot case, use a bit wet & dry to clean off any oxidisation on the metal to expose new metal, the solder will flow much better and you'll get a nice clean connection.

Oh and don't blow on the joint to cool it :ugeek:

Hope this helps :)
Farmer
Posts: 167
Joined: Mon Jan 17, 2011 10:04 pm
Location: Auburn, Indiana

Re: grounded?

Post by Farmer »

This my sound stupid, but make sure your cord that you are using from the pickup to the amp is a good one. I have been expermenting with Alumitone type pickups and found my cord had a bad ground on one of the plugs. I had changed one end of this cord before, and when I changed it back I didn't get it soldered good enough... It will still give you a signal, but will be noisey. Hope this helps.... Mike
zmartin66
Posts: 6
Joined: Wed Mar 13, 2013 2:49 pm

Re: grounded?

Post by zmartin66 »

Thanks Jif and Mike!

Since I posted this I have more or less narrowed it down to one of 3 sources, a bad pup, bad soldering, or I fried my pots while teaching myself how to solder (on this last one, curious to know how plausible this is, and how one might be able to tell if a pot had been cooked?). My guitar cable is old and is no doubt contributing to some of the noise I hear, but I did try a much newer cable and know that my older one still works reasonably well with my other two guitars so I think I am OK here. I decided to order a new pub last night (Kent Armstrong single coil), and new pots and jack. While I wait for these to arrive I have been practicing soldering on scrap bits of wire and such. Hopefully one, or all of these things will help me get this all sorted out.
na4it
Posts: 101
Joined: Wed Jan 02, 2013 12:26 pm

Re: grounded?

Post by na4it »

Sometimes using a hotter iron and get on and off quicker works better. Also, get some of the really thin rosin core solder. I use 0.032 stuff.
Scott Duckworth
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