guitar pots

[christobean]

i recently got playing around with the knobs on my one strat-type guitar... there is sever buzz whenever the volume pot is not at 10, then once its at 10 it quiets down significantly.  also, both tone knobs get extremely buzzy when i turn them up at all, theyll be quiet at 0, then get worse as i turn it up. 

does anybody know where the problem is? do i need to shield everything, or is it the pots themselves that are the problem, or the soldering inside, or what. i know very little about what goes on inside a gutiar electronicly, so any help is appreciated.

thanks

[lvs]

At the guitar's side, the guitar cable is "terminated" with a resistance that equals :

- zero when the volume pot is at zero
- roughly, the volume pot resistance divided by 4 when the volume pot is at it's resistive midpoint
- roughly, the pickup's resistance when the volume pot is at maximum

This resistance change inside the guitar is normal. The resistance in the 2nd case is quite large compared to the 1st and 3th one. The higher it is, the easier it is for the cable to become a hum antenna. But normally it shouldn't cause so much trouble. You could for example check if your cable is in good condition, and that it's well away from buzzing sources. You could also check wether the ground wire to the tremolo claw is still connected. In case any soldering was done to the guitar right before the trouble started, you could check wether the jack leads were swapped by accident.

[christobean]

the tremolo could be the problem... the wire is still connected, but teh springs dont connect from that to the bridge because i blocked it off with a piece of wood. i will try putting a wire from teh bridge to the claw and see if it helps.

[christobean]

ok, i installed a wire from the claw to the bridge, and there was no difference. anyone else have a suggestion?

[Ronsonic]

plug it in, turn the guitar up, take your hands off. It should hum. Grab the strings - it should get quieter. Does it do that?

Or just ohm it from the strings to the ground at the jack. The answer should be close to 0 Ohms.

This thing where it's quiet with the volume all the way up, is this in all pickup positions?

See, you've got me convinced there is a wiring error. It's a single coil guitar, it will pick up noise. BUt it should be noisier at full volume.

Ron

[christobean]

plug it in, turn the guitar up, take your hands off. It should hum. Grab the strings - it should get quieter. Does it do that?

it does that

This thing where it's quiet with the volume all the way up, is this in all pickup positions?

yes, it happens with all positions.

See, you've got me convinced there is a wiring error. It's a single coil guitar, it will pick up noise. BUt it should be noisier at full volume.

it could very well be a wiring error, as i got this second hand, and there was some obvious modding to teh body, so the last owner might have changed some things around inside, i dont know enough about the guts of a guitar to know.  but yes, it is definately noisier when the pot is not at full volume. however, it is dead silent at 0.

thanks a lot for the response

[Ronsonic]

We've verified that the strings are grounded and that it's miswired.

Lift off and nuke from orbit. It's the only way to be sure.

I would simply go in and just redo it. If you're posting here, you've got a soldering iron. The parts are either all there and work or some are broken and need replaced anyway. It isn't a big job, two hours taking your time and getting it right. Diagrams are everywhere.

Why fuss with it. It's almost impossible to guess at a distance just what's been screwed up. But once you open it, it may be obvious. If you open it with the mindset that you're prepared to redo everything and just find a problem like a failed ground then you can be happy and relieved.

ROn

[christobean]

ok, sounds like a plan.  are there any special supplies i'll need, like special types of wire or anything? thanks agian.

[rockgardenlove]

I can take a good guess...
The output from the pot should be in the middle, with one of the outer lugs grounded and the last lug the input.  Is this how it's wired?

[ashcat_lt]

guitarnuts is a great place for answers to guitar wiring questions.  here's a link to the site which has what seems to be the internet standard article for shielding and wiring a strat.  and here's the forum, full of great, knowledgeable people who'll be happy to help.

[Ronsonic]

ok, sounds like a plan.  are there any special supplies i'll need, like special types of wire or anything? thanks agian.

You'll be amazed at how special the wiring in a guitar isn't.  You'll probably also be surprised at cheesey little pots and a crap switch. Up to you what to replace - depends on the quality of the guitar. If it's a keeper and you're going to be using it, I'd upgrade. $2 will get you a better pot than what's in there and $10 will get as good a switch as it gets, the jack won't be much either. That and some wire and you've got the parts.

Ron

[slacker]

We've verified that the strings are grounded and that it's miswired.

Surely if it makes a noise until you touch the strings it means the strings aren't grounded? By touching them you're making the ground connection.

[christobean]

thanks all, ive gone over to guitarnuts and there is a ton of info there. ill probably take this over there, and come back with some final results. thanks!

[Ronsonic]

We've verified that the strings are grounded and that it's miswired.

Surely if it makes a noise until you touch the strings it means the strings aren't grounded? By touching them you're making the ground connection.

If the strings were not connected to instrument ground (the sleeve connector on the output jack) then touching them would make no difference.

Ron

[slacker]

Sorry, you're right. I'm probably being a bit thick, but If they're already grounded why would touching them do anything to the hum? 

[christobean]

ok, i shielded and star-grounded my axe, and now the hum is a lot less.  the buzzing nowincreases evenly as i turn up the volume, like one would expect, and the buzz just 'changes tone' when i turn the tone knobs, aka gets more trebley or bassy

[Ronsonic]

Sounds like a healthy single coil guitar.

Ron

[ashcat_lt]

yeah, it was miswired.  you took it apart and rewired it based on instructions from guitarnuts.  Any idea what was wrong now?  What did you change to get where you are now?

[christobean]

im thinking it was a combo of half assed wiring and bad soldering and stuff, there were so many random wires i just ripped everything out then there was they standard strat wiring left.