HELP! Wiring dilemma: dramatic treble drop when vol knob below 10 (you'll probably laugh)

Smashies

Platinum Supporting Member
Messages
2,591
TGP,

As you can imagine by reading the title, I've got a guitar, a circa '98 Squier Vista Series (MIJ) Jagmaster, that has a wiring issue. It's equipped with the ol' Seymour Duncan Jazz/JB humbucker pickup combination (don't judge...okay judge, it's fine), and I wanted to try to take advantage of the pickups' ability to do coil splits. So I went to a place that conventionally everyone adores on TGP called Guitar Center (don't ju...you're judging! Okay I don't blame you). While there, the tech suggested two things: (1) an orange cap, and (2) to wire the pickups in parallel when the tone pots are pulled up instead of a coil split. Another caveat (you'll see in the photos): before I got this done, a buddy of mine and I applied shielding to the inside in anticipation of reducing hum for when the pickups were wired to engage single-coil when pots pulled back.

The end product: if I roll my guitar's volume knob below 10, and I mean even to 9.5, it sounds like I'm rolling my tone knob back to almost 0.

Lately I installed .11s on this guitar from .10s and had my guitar instructor do the setup (and THAT I know he did a great job of). Since you have to remove the neck on this guitar to adjust the truss rod, I asked that he shoot some photos of the inner wiring for me to use later for consultation, like in a friendly TGP forum!

My teacher and I are almost positive these pots are 500k pots. (1) I specifically told the GC tech to install 500k push-pull pots, and (2) it doesn't seem to make sense anyway to have 250k push-pull pots.

Something I'm not 100% positive of (and the photos may indicate this), but the GC tech mentioned something about how convenient it was to have the shielding because he'd be able to wire his grounds to it. (I have ZERO idea what this means, but I thought it might be worth mentioning).

What I suspect: the cap is valued for single coils (I think). I looked up on Stew-Mac on the page where they sell orange drop caps, and it says that the value ".047uF" is usually given the code "473K" and is traditionally used for "Single-coil guitars, many basses." This cap reads "473J" -- while I'm not sure what the difference betweenthe "K" and "J" suffix is, the first three numbers suggest this cap is for single coils.

I've purchased an Emerson paper-in-oil cap: a yellow one with the value .022uF which is advertised as commonly used for "humbucker tone."

Without further ado, here are the photos:









QUESTIONS:

(1) Is the cap the issue?
(2) Is it even wired properly?
(3) What else can I learn from this?
(4) Does anyone have any Tylenol?


Thank you for your patience and help, TGP!
 

Papanate

Member
Messages
19,859
The Capacitor is a 47pF with the 'j' meaning
it has a tolerance of +/- 5%.

Is the Capacitor wired to the Volume or Tone potentiometer?
And why did you have Push Pull Pots installed? Are you splitting the
coils on your Humbuckers?
 

Brian N

Member
Messages
1,710
To answer the most important question, the cap is not the issue. Somewhere in your guitar, some component is touching the copper shielding that shouldn't be. This same thing happened to me when I put shielding in my guitar.

Regarding the .047uf cap, they are generally used for single coils, but many people use them for humbuckers. It's a matter of preference. If your tech told you it was a .022uf (which are generally meant for humbuckers, but again, it's preference) then he is either incompetent or couldn't be bothered to check. If he told you it was .022 or you asked for .022, don't use that tech anymore; you shouldn't have to check his work like that.

They do make 250k push-pull pots, but he probably gave you 500k. Only a complete dimwit would fail to check that.

Regarding the push-pull thing putting the pickups in parallel- the pickups are wired in parallel by default when you're in the middle toggle position. You don't need a push-pull pot for that. What he probably meant was for them to be wired in SERIES. The fact that he mixed those up adds to my suspicion that your tech doesn't know his stuff. On top of that, he should've found the tone issue youre experiencing rather than just sending it along for you to find.
 

Smashies

Platinum Supporting Member
Messages
2,591
To answer the most important question, the cap is not the issue. Somewhere in your guitar, some component is touching the copper shielding that shouldn't be. This same thing happened to me when I put shielding in my guitar.

Regarding the .047uf cap, they are generally used for single coils, but many people use them for humbuckers. It's a matter of preference. If your tech told you it was a .022uf (which are generally meant for humbuckers, but again, it's preference) then he is either incompetent or couldn't be bothered to check. If he told you it was .022 or you asked for .022, don't use that tech anymore; you shouldn't have to check his work like that.

They do make 250k push-pull pots, but he probably gave you 500k. Only a complete dimwit would fail to check that.

Regarding the push-pull thing putting the pickups in parallel- the pickups are wired in parallel by default when you're in the middle toggle position. You don't need a push-pull pot for that. What he probably meant was for them to be wired in SERIES. The fact that he mixed those up adds to my suspicion that your tech doesn't know his stuff. On top of that, he should've found the tone issue youre experiencing rather than just sending it along for you to find.
This helps! So, does the presence of shielding NOT create a problem as long as the suspect component is not touching the copper shielding? What might the suspect component be?

Regarding the Emerson .022 cap: that one is not installed. I just have that uninstalled and on standby in case the cap that IS installed (which is a .047uF, I believe) is the culprit or, if it's not the culprit but it creates an undesired tone, I'd have the Emerson cap on standby to replace it.
 

Brian N

Member
Messages
1,710
This helps! So, does the presence of shielding NOT create a problem as long as the suspect component is not touching the copper shielding? What might the suspect component be?

Regarding the Emerson .022 cap: that one is not installed. I just have that uninstalled and on standby in case the cap that IS installed (which is a .047uF, I believe) is the culprit or, if it's not the culprit but it creates an undesired tone, I'd have the Emerson cap on standby to replace it.
No, the cap is certainly not the culprit here. If the issue is with the volume pot, I would start there. The shielding should be grounded, so anything touching the shielding that shouldn't be grounded will cause problems. It's hard to know what is touching when you put that pick guard back on, I would just take electrical tape and stick it on anything that might be touching the shielding. The backs of the pots can touch (they are supposed to be grounded) but the lugs shouldn't.
 

Smashies

Platinum Supporting Member
Messages
2,591
No, the cap is certainly not the culprit here. If the issue is with the volume pot, I would start there. The shielding should be grounded, so anything touching the shielding that shouldn't be grounded will cause problems. It's hard to know what is touching when you put that pick guard back on, I would just take electrical tape and stick it on anything that might be touching the shielding. The backs of the pots can touch (they are supposed to be grounded) but the lugs shouldn't.
Very helpful! Thanks!
 




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