OT: Guitar-related question

[Ponchus]

Sorry guys this is a little off topic, but I have a guitar related question. I recently assembled my first guitar, using Warmoth parts. It's a Strat style guitar, 3 single coil pickups, 1 volume and 2 tone pots. The pickups are overwound GFS Greybottoms.

I followed the directions on Guitarnuts.com. He has an article about star grounding and shielding a Strat. I followed those instructions, and the guitar does work.

However, there is quite a bit of buzzing from the guitar when the volume knob is not at its extremes (off or volume max). So if my volume is all the way down, I get no sound, as expected. If I turn up the volume to anything below maximum, there is a horrible buzz. Once I hit max volume on the volume pot, the buzz subsides quite a bit.

Any suggestions of what I should look for?

Some notes on my build that might help:
1. The pots I got were from effectsconnection.com. I was ordering parts for some pedal builds, and noticed that he sells guitar pots. So I bought a 500k for volume, and two 250k pots for tone. The pots, however, were huge. Or at least, they were bigger than the ones that came in the Squier I took the pickguard from. In fact, I had to drill larger holes into the pickguard for the pots to fit. This made fitting all the electonics into the guitar cavity a little harder. I'm worried that maybe a pot shell is touching the tin foil I used to shield the cavity. Could this lead to my problem? Or would my problem not subside at max volume?
2.  I lined the back of the pickguard with tin foil, as well as the entire guitar cavity. I did not, however, line the place where the guitar jack sits. Do I need to?

Thanks

[JimRayden]

Any suggestions of what I should look for?

Check yer grounds.

---------
Jimbo

[jonathan perez]

Any suggestions of what I should look for?

Check yer grounds.

---------
Jimbo

why, did he drop a screw thatll defeat buzz?



GOTTAHAVEEMGOTTAHAVEEMGOTTAHAVEEMGOTTAHAVEEMGOTTAHAVEEM

[ashcat_lt]

Why not ask the folks at the guitarnuts forum ?  They're real nice.

I've seen this pop up a couple times recently.  Seems it could have something to do with which lug you've connected your pickup hot wires to.

[Ronsonic]

Do you have a ground wire connected to the bridge? For a strat type this is usually a wire from the control cavity to the spring claw.

Ron

[axg20202]

Hi,

it sounds like the pots could be of the 'no load' variety? This could give you clue because I think these are effectively bypassed when at maximum. It could be that your problem is associated with how the volume pot is wired, because when it is effectively taken out of the circuit (by setting at max volume), the problem is reduced. Just a thought. Double check how your volume and tone pots are wired.

Andy.

[Opencan]

I can't think of a logical reason beside the pot being messed up and the foil conduct current to places he shouldn't.
If not the shielding, grounding or stuff like that, because it hums only in certain volume pot positions.
MIGHT be the wiring, if you had it totally wrong or something.

Try replacing the pot, seems the most logical idea. Any 250k-1M pot will work for testing this.

The things that should be grounded are; bridge, pot shells \ toggle switches shells, one polarity of any pickups (unless wired in series), shielding and the negative wire from the output jack. It should be all soldered in one place, I preffer the volume pot usually.

I can't imagine myself using the large pots in my squier strat, I barely got all the wires in there X_X (using a 3PDT toggle to make the selector switch go from "normal" positions to "normal" position into the middle pickup in series)

[Ponchus]

Thanks for the help.

I will definitely double check everything, but I am positive that I wired everything "correctly". Now that's not to say that maybe there's a cold joint somewhere. But I checked this a milion times before putting everything back together, and I'm positive that I didn't cross wires.

Also, I do have a ground wire running to my fixed bridge.

I am thinking of just replacing the pots altogether for normal sized ones. Problem is I've already drilled bigger pot holes into the pickguard 

[Ronsonic]

<curmudgeonly rant>
What you think of as "normal size pots" I think of as "the stupid dime bodied, satan shafted crap pots that they've been screwing up gear with for years." It is the Squeir pots that are the wrong size. The full sized pots that you put in there are what God, Leo and all of loving humanity believes are the right size to put in a guitar. Look at it this way, if you pay Fender $150 for a guitar you get the little ones. If you pay $2,000 you get the large body ones. There is a reason for that.
</curmudgeonly rant>

Let me shorten that up, the pots aren't the problem.

There is some kind wiring problem to be diagnosed and corrected. Wish I could give you more than that. Is there any chance of jack wiring being reversed or of the leaf of the jack being shoved against your shielding paint when you plug in? or .....

Ron

[markm]

Personally,
Having played an unshielded Telecaster for years, I see no real neccessity for all of the "shielding" that some swear by.
If one is to go this far shielding an instrument, they should take it a step farther and shield the rest of the equipment they are using as well I would think....
There's alot to be said for an unshielded instrument that is properly grounded.   

[axg20202]

I forgot to ask, did you ground the shielding and ensure that all the shielding material is connected together? It would not have much effect if not because you want to direct interference to ground. Also, if you are concerned that maybe you have a grounding issue caused by a pot touching something else, why not try applying some electricians insulating tape to the pot casing and see if that cures the problem? Personally I think it is mostly likely that something is just wired incorrectly. Another possibility is that you have a poor solder joint somewhere. Your soldering points should be nice and shiny not dull. The solder and resin in the solder should make it flow nicely as you make each connection. 

Lastly, follow a logical process of elimination and you will find the problem. Did the buzzing exist before you applied the shielding or did you do all the wiring and shielding at the same time? Perhaps remove the shielding and see if that clears it up. If you really can't find the problem I would just take it to a tech and save yourself some grief.

Andy.

[Opencan]

If you really can't find the problem I would just take it to a tech and save yourself some grief.

Andy.

But then you miss all the fun!
I always debug my things alone, its the BEST way to learn for next time.

the most logical thing to check is the volume pot connection to the ground. its the only thing I can think of with the exact same characteristics. When the put is at 0% to the ground it should be perfectly fine, but when you change that setting problems should pop out.
triple check it with a multimeter (from the middle terminal while dialed all the way to ground to lets say the bridge).

[black mariah]

Here what you do... open up the guitar and start touching things while the guitar is plugged in and turned on and buzzing like crazy. When the buzz goes away or gets quieter strap a ground wire to whatever you're touching. 

Can't tell you how many times I've opened up a guitar someone THOUGHT they wired correctly and ended up fixing it in about ten seconds using that method.

It is very rare that a pot is the source of a buzz. I've only seen it a few times, and all of those were with very old and tarnished pots. Typically a pot either makes noise or it doesn't.

Does the buzz lessen with certain pickup combinations? If so, you may have something wired out of phase without knowing it.

[ashcat_lt]

saying you're sure the thing is wired correctly is not the same as checking.  i suspect you've got the wire from the tip of the jack connected to the outside of the pot, rather than the wiper.  this can cause the problem you're experiencing.

[Opencan]

Here what you do... open up the guitar and start touching things while the guitar is plugged in and turned on and buzzing like crazy. When the buzz goes away or gets quieter strap a ground wire to whatever you're touching. 

Can't tell you how many times I've opened up a guitar someone THOUGHT they wired correctly and ended up fixing it in about ten seconds using that method.

It is very rare that a pot is the source of a buzz. I've only seen it a few times, and all of those were with very old and tarnished pots. Typically a pot either makes noise or it doesn't.

Does the buzz lessen with certain pickup combinations? If so, you may have something wired out of phase without knowing it.

Thats a great method! The only bad thing about it is that I haven't thought of it before 
That will surely help me in the future

[Ponchus]

Sorry in advance for this long post. 

So here's where I stand. If you go to this link at Guitarnuts- http://www.guitarnuts.com/wiring/shielding/innards.php - you'll see the exact wiring scheme that I used (note that there a digram for standard wiring, and a diagram for Shielded wiring- I used the shielded wiring scheme). When star-grounding, you're no longer attaching the shells of all the pots together. Rather, all ground points come together at one point. I used a spare washer, and attached all ground wires to that washer (Guitarnuts suggests a ring terminal, but I didn't have one). I then insulated the washer and all attached points. The ground from the trem is attached separately to the foil in the guitar cavity.

Anyway, I'm absolutely certain that I wired everything up correctly and did not reverse any wires, because I double checked, triple checked, and quadruple checked. However, that's not to say that I don't possibly have a cold joint somewhere. I will check, but keep reading.

As per Guitarnuts, when you shield the back of the pickguard with foil, the pot shells become grounded when you attach the pots to the pickguard. If you then ALSO wire one pot shell to the next (which is normally how guitars are wired), then you've created a ground loop, which is apparently bad. When I was stating that the pots I received were too large, that's exactly what I was worried about. The pots are grounded via the foil on the pickguard. But since the pots are so big, they are VERY close to touching the bottom of the guitar cavity as well (which is also lined with foil). Wouldn't this also create a ground loop? I'm not really sure if the pots are in fact touching the bottom of the cavity, but it's close.

I agree that Squires uses small, shitty pots. These pots from Effectsconnection, however, are waaaay too big. For example, not only did they not even fit through the holes in the pickguard (I had to drill bigger holes), but when I did attach the pots and installed the knobs, the knobs are basically "floating" a good inch above the pickguard. So the knobs are actually higher than the strings LOL. Also, the pots resist too much to being turned. They are high quality, and all high quality pots that I've used require more force to turn (unlike shitty pots, which turn with the faintest touch, or with a passing breeze). If I want to do a volume swell, for example, I want a smooth, easy turning pot; not a stiff knob. I need a good happy mediium.

UPDATE- so anyway, after all that rambling, I need to mention that I haven't worked on this problem yet. I went to Sam Ash, bough a new pickguard and new pots (Fender brand, $6 a piece). However, when I went home, I couldn't recreate my original problem, so I haven't done anything yet. And this is where this gets weird.

In my rehearsal space, I play out of a Fender Bassman head. I have various pedals, all built through Tonepad, GGG, etc. The first day that I played the new guitar, I had this problem with the buzzing. I tried changing the order of my pedal chain, and voila the problem was gone. That was the only place I plugged the guitar in at that point. I don't remember the details, but it was something like Ross Compressor > TS8, vs TS8 > Ross Compressor. One way buzzed, the next way did not.

I forgot about it, and went to my friend's house. Plugged into his DI box for his computer (no pedals), and had the buzzing problem. Posted my original message to you all. Went and bought a new pickguard, pots, etc. Went home, plugged into my battery powered Fender amp, problem is gone. Plugged into my Line 6 Guitarport, no problem either. So I have not been able to recreate this at home, but did experience the problem at my rehearsal space and my friend's house. Which worries me. I need a guitar that will not crap out on me depending on my location.

I think I will still replace those pots and pickguard, just for peace of mind, unless you guys have any other suggestions? Well, I'm definitely replacing the volume pot regardless though...

Thanks again everyone!

[Opencan]

If the shells create a ground loop, isolate them. put electrician tape on it and thats about it.

might be something like a glue buble in the foil that squeeshed and disappeared or practicly anything. if you'r afraid they shells make this thing, wrap 'em up just in case.

[axg20202]

Same cable used each time? IME, this kind of intermittent and seemingly random problem is almost always caused by a poor instrument cable.

Andy.

[Ponchus]

Sorry, already thought of that  This happened with 2 different cables, one being pretty new.