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Discussion Starter · #1 ·
Hey guys, I'm using this wiring diagram:

2H_5WSPL_1V_1T.pdf

I'm using a 500k tone pot, but the pdf doesn't specify the value.

Everything except the tone pot works great - the coil splitting, the hum bucking, etc.

The tone pot has no discernable effect for 95% of its travel except very near full clockwise - where it suddenly kills the volume completely. Is there a mistake in Seymour Duncan's diagram (probably not)? Or have I wired a mistake? I've already tried a different pot and different cap - with the same problem.

I'm thinking the wisdom of experience may be of value here. Anyone know what I've done wrong? Thanks.
 

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Post a pic of your work
 

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The SD drawing simply looks wrong. It should look like this:
Good eye!!

I wonder how many others have been "frustrated" by this error as SD wiring diagrams are so often used.

This is a screenshot of one approach to the correct wiring.
Screen Shot 2019-08-21 at 9.11.14 AM.png
 

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It wouldn't be the first time in history that someone assigned to whip up a file did some quick copy-and-paste without checking it over. I've done it myself many a time. Not a problem if the information is for someone with a bit of expertise. But the drawings are clearly directed at folks who need to be told "Put this over here", without any accompanying explanation, so one needs to be a little more careful in checking your work. I'm pretty sure it's not Seymour's fault. ;)
 

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Discussion Starter · #9 ·
Thanks guys! I was outside all day putting up a new railing on my steps. I'll make the change and report back.
 
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Patrick,

Since you are going to be in there anyway, I will suggest you experiment with a bidirectional tone control. Tie the wiper of the tone pot to the input lug on the volume. Solder the .047uf cap from one outside lug (preferably the one normally used for ground on a volume pot) to the ground/shield/back, and solder a .01uf cap from the other outside lug to ground. The midpoint will be least treble cut, and rotating in each direction will give a different kind of treble cut. If you don't like it, simply remove the smaller-value cap and it will work as normal.
 

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Discussion Starter · #11 ·
Thanks all who helped out. Indeed the drawing from SD was incorrect. I will alert SD if I can remember to do that later.

I checked the cap as suggested but it was still good. I made the change Mark suggested and it worked to fix the zero volume problem at full travel. But it still didn't behave like my other guitars. There was no discernible tone change until nearly full clockwise on the tone knob when there was what sounded like a step change to dark muddy tone. There was even a barely audible click like a switch that occurred just as the tone changed to dark. I checked the pot, and it was linear 500k (the one that came with the pickups). So I wired in a 500k log pot, and it behaved as expected with a much more usable travel. But the log pot's shaft was too short to fit the guitar (it was from my pedal part stash). Then Mark's second suggestion came in handy - I did the bidirectional tone control and now I have 3 usable tone settings with that linear pot. There is still that nearly step change at max rotation, but at least I have 3 options now.

This was a cheap starter Ibanez guitar that I really liked the body shape of. Add some free second-hand SD pickups and upgraded machine heads I bought here, and now it really kills. Plus I don't care about damaging or modding it or letting the kids bang away on it. My next addition will be to do away with the tone knob entirely and add in a wah pedal on that knob. I know there is a commercial product you can buy and install that does this, but I will roll my own. Perhaps Anderton's wah-antiwah. I plan to add chrome pickup covers for looks - I'm also curious to know if the tone will change much.

Everyone should have a beater guitar they are not afraid to dig into and mess around with!
 
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Thanks all who helped out. Indeed the drawing from SD was incorrect. I will alert SD if I can remember to do that later.

I checked the cap as suggested but it was still good. I made the change Mark suggested and it worked to fix the zero volume problem at full travel. But it still didn't behave like my other guitars. There was no discernible tone change until nearly full clockwise on the tone knob when there was what sounded like a step change to dark muddy tone. There was even a barely audible click like a switch that occurred just as the tone changed to dark. I checked the pot, and it was linear 500k (the one that came with the pickups). So I wired in a 500k log pot, and it behaved as expected with a much more usable travel. But the log pot's shaft was too short to fit the guitar (it was from my pedal part stash). Then Mark's second suggestion came in handy - I did the bidirectional tone control and now I have 3 usable tone settings with that linear pot. There is still that nearly step change at max rotation, but at least I have 3 options now.

This was a cheap starter Ibanez guitar that I really liked the body shape of. Add some free second-hand SD pickups and upgraded machine heads I bought here, and now it really kills. Plus I don't care about damaging or modding it or letting the kids bang away on it. My next addition will be to do away with the tone knob entirely and add in a wah pedal on that knob. I know there is a commercial product you can buy and install that does this, but I will roll my own. Perhaps Anderton's wah-antiwah. I plan to add chrome pickup covers for looks - I'm also curious to know if the tone will change much.

Everyone should have a beater guitar they are not afraid to dig into and mess around with!
Congrats! I can whip you up a board for a clone of the Systech Harmonic Energizer, that Frank Zappa had installed in one of his guitars, if you're interested.

Tone-pot taper is a curious thing. Pots may say that they're linear or log, but that's really only an approximation. That said, f there is a discernible "click" in that pot and it's not something with an actual centre detente, then there is likely something amiss with the pot. You should probably get something appropriate with a suitable shaft, from Jon at Next Gen.
 
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