Hum is now caused by treble. unreg?

[unreg]

Hi all! 😀

Last night, after resoldering a wire that had broken off the ground paperclip, the hum now happens conditioned on how much treble is present in the output. (Is that easily solved?) (And now both pickups work just great again! )

Like:

• If the volume knob is turned all the way to off, there is no hum.


• Turning the volume knob up increases treble and, at the same time, increases hum.


• However, if the tone knob is off, the volume knob could be turned all the way to max and there is no hum.


• If the tone knob is at max, then the hum created by turning the volume knob is significantly louder as it increases.

I’m excited that the hum problem now depends on treble! 😀 What would you do to remove the treble hum? Replace the tone pot, again?

[frets]

Unreg,
I think you have a ground loop problem. Pots grounded to each other?

[ashcatlt]

There's no such thing as a ground loop inside a guitar. There may be redundant ground connections, but that's never an actual issue either.

Does the noise change when you touch the strings, bridge, or jack sleeve?


Edit - I know the "ground loop" thing came up on the original GN site, but we have totally debunked that at least a couple of times around here over the years. It's seriously not a thing. IF, though, you're using the back of the pots as a signal ground, that very much could be the issue just because it's tough to get a good solid connection that way, so it could just be a bit hinkey. The ground connection to the pot cases is best practice for shielding purposes, but we should not rely on a shield connection to carry our signal grounds. The "bottom" signal wires from pickups, and the grounded lugs of the volume and tone pots really should go to the jack via wire, not through shielding or pot cases.

[newey]

Nov 25, 2020 17:09:29 GMT -5 unreg said:

If the volume knob is turned all the way to off, there is no hum.
Turning the volume knob up increases treble and, at the same time, increases hum.

This would seem to be normal operation if there is "hum" in the circuit. Is what you're hearing the usual single coil hum that an unshileded guitar with single coils would make?

This, however:

However, if the tone knob is off, the volume knob could be turned all the way to max and there is no hum

seems to indicate a dodgy connection to that tone pot, or a bad pot. I'd first try resoldering those connections (and mind particularly what ashcatlt said about gorunding to the back of the pot). If that doesn't work, then swap out the pot.

[Yogi B]

Nov 27, 2020 8:23:26 GMT -5 newey said:

Nov 25, 2020 17:09:29 GMT -5 unreg said:

If the volume knob is turned all the way to off, there is no hum.
Turning the volume knob up increases treble and, at the same time, increases hum.

This would seem to be normal operation if there is "hum" in the circuit. Is what you're hearing the usual single coil hum that an unshileded guitar with single coils would make?

That's my question too -- it is 50/60Hz mains 'hum' (which would always be below the cutoff frequency of, and thereby should not be affected by, the tone control) or is it higher frequency 'noise' which will be reduced by the tone control in exactly the same way as the treble frequencies from the pickups.

[unreg]

Nov 26, 2020 20:14:15 GMT -5 ashcatlt said:

IF, though, you're using the back of the pots as a signal ground, that very much could be the issue just because it's tough to get a good solid connection that way, so it could just be a bit hinkey. The ground connection to the pot cases is best practice for shielding purposes, but we should not rely on a shield connection to carry our signal grounds. The "bottom" signal wires from pickups, and the grounded lugs of the volume and tone pots really should go to the jack via wire, not through shielding or pot cases.

Very good to learn ashcatlt so thank you! My volume pot’s grounded lug is connected to its pot case, bc every volume pot installation video I’ve watched encourages everyone to bend the grounded lug towards the pot and solder that.

However, my guitar came with a short bare solid wire soldered between that volume pot’s casing and its ground lug. I just transferred that wire, from my old volume pot, to ground my new volume pot. My new volume pot’s casing is grounded to the jack via wire, so that bare wire “should” work... or so said those videos.

So, I’ll take that solid bare wire away? Yes, I’ll do that.


newey I’ll try what you said to; though I can’t remember now; need to sleep.


Thank you frets, ashcatlt, and newey!

[unreg]

Nov 28, 2020 3:53:35 GMT -5 Yogi B said:

Nov 27, 2020 8:23:26 GMT -5 newey said:

This would seem to be normal operation if there is "hum" in the circuit. Is what you're hearing the usual single coil hum that an unshileded guitar with single coils would make?

That's my question too -- it is 50/60Hz mains 'hum' (which would always be below the cutoff frequency of, and thereby should not be affected by, the tone control) or is it higher frequency 'noise' which will be reduced by the tone control in exactly the same way as the treble frequencies from the pickups.

hmmm... Yogi B and newey, I’m undecided on the sound being ’hum’ or ’noise’. I can’t use my guitar now... will have to respond better tomorrow sometime, sorry.

[ashcatlt]

Nov 28, 2020 3:59:27 GMT -5 unreg said:

So, I’ll take that solid bare wire away? Yes, I’ll do that.

I mean, you can leave the connection to the pot case itself, but the wire from the jack should go to the actual lug. I personally never actually solder to a pot case. Instead I’ll use an o ring or just a washer around the pot shaft to make that shield connection. Is the rest of the cavity shielded?

I don’t think you answered my question about how/if the noise changes when you touch things.

The actual 50/60Hz fundamental line frequency isn’t always much of an issue, but we also have all of the harmonic multiples of that frequency which do pop up in more important frequency bands. But then there’s all sorts of other higher frequency EM radiation pulsing around us all the time, too. My suspicion is that you’re hearing some higher frequency noise and it just gets attenuated along with the rest of your treble content when you turn the T pot down. But then I’m not hearing what you’re hearing, so who knows?

[unreg]

Nov 28, 2020 11:11:39 GMT -5 ashcatlt said:

Nov 28, 2020 3:59:27 GMT -5 unreg said:

So, I’ll take that solid bare wire away? Yes, I’ll do that.

I mean, you can leave the connection to the pot case itself, but the wire from the jack should go to the actual lug. I personally never actually solder to a pot case. Instead I’ll use an o ring or just a washer around the pot shaft to make that shield connection. Is the rest of the cavity shielded?

There is black paint covering the cavity base and part of the cavity walls. That paint does allow current to pass through and it has been grounded.

I don’t think you answered my question about how/if the noise changes when you touch things.

The noise (it’s a buzz; not hum) does change depending on the knobs.

• If both vol and tone are max, there is a loud buzz that vanishes when grasping the tone knob or touching all the strings.


• If only the vol is turned off, the buzz is happily missing until grasping the vol knob; that resulting buzz is lower in pitch, but just as loud. Then it disappears after releasing the vol knob.


• If the tone knob is turned off too, that lower pitched buzz still occurs when grasping the vol knob, but it’s quieter.

Gtg... sry

[unreg]

Nov 28, 2020 11:11:39 GMT -5 ashcatlt said:

Nov 28, 2020 3:59:27 GMT -5 unreg said:

So, I’ll take that solid bare wire away? Yes, I’ll do that.

I mean, you can leave the connection to the pot case itself, but the wire from the jack should go to the actual lug.

So, the wire from the jack should go to the volume pot’s ground lug. Currently, the jack’s ground wire goes to the star grounding paper clip and then a wire runs between that paper clip and the vol pot’s ground lug. So, remove from paper clip and... um is there a y-adapter wire? In my head the jack’s ground wire needs to go, both, to the paper clip and to the vol pot’s ground lug. How?


edit: Ooooh, ashcatlt, you said the ground should not go through shielding or pot case, and it does go through vol pot case bc the stranded wire from that star ground paper clip is soldered to the pot case. And then the short bell wire transfers that ground to the vol pot’s ground lug. So, now all I need to do is desolder that stranded wire from the vol pt case and solder it to the vol pot’s ground lug!

And, frets, yes I believe my star ground paper clip could provide a possible ground loop bc all grounds go to it (and from it, I guess), but ash seems to know that ground loops don’t exist inside a guitar... I’ll just try the small change above right now.

[unreg]

If anyone cares, I’ve successfully desoldered that stranded wire from the volume pot case and soldered it to the volume pot lug!

PRAISE GOD!!

It sounds much better to me now, but there is still some higher pitched ’noise’, Yogi B, and so, newey, tomorrow I’ll make sure all the connections on the tone pot lugs are resoldered.

The case of the tone pot needs ground, imo, bc the green “chiclet” capacitor is soldered to it, but I’ll check that tomorrow too.

Thank you so much ashcatlt, and newey! I hope it’s almost done.

[newey]

Nov 29, 2020 0:31:53 GMT -5 unreg said:

The case of the tone pot needs ground, imo, bc the green “chiclet” capacitor is soldered to it, but I’ll check that tomorrow too.

The tone control won't work if the cap isn't grounded in some fashion. If you are using a star grounding scheme, typically the cap would get grounded there, along with all the other ground wires. But if it's already soldered to the back of the pot, just ground that.

[unreg]

ashcatlt, newey, and Yogi B

Nov 26, 2020 20:09:48 GMT -5 frets said:

Unreg,
I think you have a ground loop problem.

Actually , maybe my grounding the tone pot and my green “chiclet” capacitor with the same blue colored dual wire is a problem... bc, after grounding the capacitor with the blue wire’s ground wire, I grounded the tone pot with the blue wire’s signal wire.

Maybe I’ve asked this before (?): Is using a signal wire to ground a pot bad? Am thinking that ground wires ground bc they are made of a different material.

Please help me to do this correctly; please help me to understand.


Is this a good solution:

1.) Desolder my capacitor’s ground wire, and the actual real ground wire, from the back of my tone pot.

2.) Bend the capacitor’s ground wire and wrap it through my tone pot’s ground lug.

3.) Wrap that actual real ground wire around my tone pot’s ground lug.

4.) Solder those wires to my tone pot’s ground lug.

5.) Snip that exposed signal wire since it won’t be used anymore.


It seems like a possible good solution to me, but it would be super kind if you all gave me your experienced opinions about my 5 step “solution”.


edit: Just want you all to know that the other ends of both of the blue wire’s wires are soldered to the star grounding paper clip.

[newey]

Nov 29, 2020 21:33:01 GMT -5 unreg said:

Actually , maybe my grounding the tone pot and my green “chiclet” capacitor with the same blue colored dual wire is a problem... bc, after grounding the capacitor with the blue wire’s ground wire, I grounded the tone pot with the blue wire’s signal wire.

Maybe I’ve asked this before (?): Is using a signal wire to ground a pot bad? Am thinking that ground wires ground bc they are made of a different material

I'm not really following your verbal description of what you now have, nor of what you're planning to do. As a general rule, we want "shield wires" separate from signal wires until they reach a common grounding point, whatever that point may be. By "shield wires", I mean wires whose purpose is to help reduce noise, not carry signal. These include the frame grounds from one's pickups, the string/bridge ground, wires that connect to any conductive shielding such as copper foil or conductive paint, as well as any ground wires for switch frames, pots or other components.

But this is a matter of "good housekeeping" rather than electrical necessity. The idea is twofold- first, your signal connections should be more certain, more secure, than being grounded in some iffy fashion through shielding, and second, there is a theoretical possibility of some excess noise if signal runs through the shields.

But recall that vintage HBs from Gibson and others used a single "hot" wire surrounded by a braided shield wire that did double-duty- it was gounding the frame of the pickup and was also the connection to one end the pickup coil. So, this is more an issue of being extra careful than anything else.

None of this has anything to do with the type of wire used.

[unreg]

Nov 30, 2020 6:41:53 GMT -5 newey said:

Nov 29, 2020 21:33:01 GMT -5 unreg said:

Actually , maybe my grounding the tone pot and my green “chiclet” capacitor with the same blue colored dual wire is a problem... bc, after grounding the capacitor with the blue wire’s ground wire, I grounded the tone pot with the blue wire’s signal wire.

Maybe I’ve asked this before (?): Is using a signal wire to ground a pot bad? Am thinking that ground wires ground bc they are made of a different material

I'm not really following your verbal description of what you now have, nor of what you're planning to do.

Just to be more clear: my “dual wire” refers to a blue wire-case that contains two wires... a “signal wire” and a “shield wire”. Sorry for not knowing the appropriate term.

Nov 30, 2020 6:41:53 GMT -5 newey said:

None of this has anything to do with the type of wire used.

Thank you newey!

After following steps 1-4 last night, my guitar started without high-frequency noise or “buzz”, but then a tinier bit of “buzz” materialized audibly. The two resistors are soldered between the 1st (ground) and 3rd lugs on my tone pot. I haven’t touched the 2nd or 3rd lug yet, but I feel that the 3rd lug may be the cause of the tiny buzz bc that lug is not entirely covered with solder. The resistor wires are “soldered” to one side of that lug’s loop, and I think that I should cover the entire lug with solder to increase the resistor’s signal transmission possibility.

I’ve read you all talking about how solder doesn’t always equate a signal transmission.

Thank you newey for your entire response! 😀


ashcatlt, now both of my pots are free of connections! There’s a small bit of solder on the tone pot case, but I didn’t take time to remove it bc I didn’t want to overheat the pot.

[newey]

Nov 30, 2020 15:44:35 GMT -5 unreg said:

The two resistors are soldered between the 1st (ground) and 3rd lugs on my tone pot. I haven’t touched the 2nd or 3rd lug yet, but I feel that the 3rd lug may be the cause of the tiny buzz bc that lug is not entirely covered with solder. The resistor wires are “soldered” to one side of that lug’s loop, and I think that I should cover the entire lug with solder to increase the resistor’s signal transmission possibility.

Why do you have resistors soldered there? Did you mean capacitors? If so, why are there two and why are they soldered between the first and 3rd lugs?

[unreg]

Nov 30, 2020 16:08:14 GMT -5 newey said:

Why do you have resistors soldered there? Did you mean capacitors? If so, why are there two and why are they soldered between the first and 3rd lugs?

Resistors are soldered there bc I had awful experiences playing guitar, after replacing my neck pu, since the guitar’s tone had way too much treble. Therefore, I found a forum somewhere after days of searching and asked if it’s possible to edit my guitar’s electronics to reduce treble levels sent to the amp.

A genius responded with an encouragement of adding resistors between the 1st and 3rd lugs of my tone pot. And, he explained in great detail how and why they would work as I wanted, so I followed his advise. PRAISE GOD!! The tone is wonderful now!

Though, I don’t remember why they work; nor do I remember what forum I asked that question so long ago.


(I don’t expect a reply to this post bc I’ve explained this three times here at guitar nuts2 and no one has ever replied.)


Oh, I do remember him explaining about resistor sizes and that certain sizes affected treble differently. And I asked if two resistors could be used; he replied validating my question and with a confirmation.

[frets]

Hi Unreg,
Have you shown the guys a photo of your harness? Maybe you have and I missed it. But if not, posting a photo of it all will help with understanding all the permutations you’ve discussed. Just a thought💡

[unreg]

Nov 30, 2020 18:28:01 GMT -5 unreg said:

Oh, I do remember him explaining about resistor sizes and that certain sizes affected treble differently. And I asked if two resistors could be used; he replied validating my question and with a confirmation.

I’ll happily explain why I asked if 2 resistors could be used...

First, a short background: I searched online for days bc I didn’t want to replace my pickups; I had read everywhere, if a guitar’s pickups give too much treble, replace them. But, I didn’t have money for that; had just purchased, and had recently installed, my neck pickup replacement from a Guitar Center; and I loved its color; and I wasn’t about to try to change the pickup top on another purchased pickup bc a.) I didn’t have the money to try another and b.) it seemed extremely scary to edit a newly purchased product.


The genius had gone through a similar situation and so he spent time trying resistors to reduce treble. He provided me a two-column list of resistor values and how they would affect treble. It seemed to me, for some reason, that I needed a resistor that had a value in between two of the list-rows; and after searching, I learned that the resistor value I thought I needed wasn’t for sale anywhere I looked. And, I seem to remember finding a wiki page that let me know the searched for value didn’t exist.

So, I used math and decided I’d like two resistors.

[unreg]

Nov 30, 2020 19:19:40 GMT -5 frets said:

Hi Unreg,
Have you shown the guys a photo of your harness? Maybe you have and I missed it. But if not, posting a photo of it all will help with understanding all the permutations you’ve discussed. Just a thought💡

Hi frets,
No, I don’t think so... though, I don’t know what you mean by “harness”. But, I have posted a photo of my new tone pot with the first set of resistors. That thread is near the top on page 2 of Guitar Wiring, and titled, “Where to buy CCR resistors? unreg?”.

I plan to send you a photo of my guitar, since you asked a while ago, once it’s finished.

[frets]

Hi Unreg,

By harness I just meant the wiring. The conversations have been interesting and I was particularly interested in the resistors you were speaking of. If I missed a photo, I do apologize. I just thought it might be helpful if we saw the whole wiring given you’re still having problems. Just a thought.

[bubbalou88]

Dec 1, 2020 14:00:09 GMT -5 frets said:

Hi Unreg,

By harness I just meant the wiring. The conversations have been interesting and I was particularly interested in the resistors you were speaking of. If I missed a photo, I do apologize. I just thought it might be helpful if we saw the whole wiring given you’re still having problems. Just a thought.

Unreg, resistor across a pots 1and 3,terminals changes the resistance value of the pot to a value lower than the value of the resistor used. This reduces treble by loading the pickup more. While this does work it is doing so at the expense of allowing the full tonal output of the pickup.

Concerning a cable with a braided outer shield. Only use that connected to ground. Center conductor is signal.
Exception: pickup with signal wire, black wire, and shield. Shield connects to ground and grounds metal on pickup while say black and color wire connect to pickup coil. Depending on pickup some will use color to ground while others may use black to ground. Yeah I know , weird

[unreg]

Dec 1, 2020 18:42:12 GMT -5 bubbalou88 said:

Dec 1, 2020 14:00:09 GMT -5 frets said:

Hi Unreg,

By harness I just meant the wiring. The conversations have been interesting and I was particularly interested in the resistors you were speaking of. If I missed a photo, I do apologize. I just thought it might be helpful if we saw the whole wiring given you’re still having problems. Just a thought.

Unreg, resistor across a pots 1and 3,terminals changes the resistance value of the pot to a value lower than the value of the resistor used. This reduces treble by loading the pickup more. While this does work it is doing so at the expense of allowing the full tonal output of the pickup.

bubbalou88, Thank you! 😀 It seems to me, I’ve read those words before. Are you the genius I received help from a long time ago in a forum of some sort?! Regardless, thank you so much for renewing my understanding of those resistors!


frets, thank you for your restated inquiry sorry that I didn’t understand that before... A photo of the wiring would be rough to take bc there are so many wires in the way of the electronics; I could push them aside but then other electronics may be covered up... and bc photos here can be only so many pixels wide; maybe I could make a larger photo open after clicking on a place holder here? Hmmm...

Dec 1, 2020 18:42:12 GMT -5 bubbalou88 said:

Concerning a cable with a braided outer shield. Only use that connected to ground. Center conductor is signal.

Thank you bubbalou88 again! Currently, that blue cable’s braided outer shield is the only part of that blue cable that’s providing ground now; guess I should snip that unused signal wire off. That signal wire was providing ground to the tone pot’s case; it’s just dangling now.

[frets]

Hey Unreg,
I completely understand wired up jungles in a cavity🌿🌿
So don’t worry about the pic. I was interested when you spoke of several resistors on a pot. We all know here how to reduce a pot’s resistance using a resistor in parallel on lugs one and three; but, it sounded like a knowledgeable guru had augmented your system with more resistors on pots than just the resistance reduction described above. So forget my request. Let us know if you’ve got the hum fixed, I’ve not read that you have. Take Care⛄️⛄️.

[unreg]

Dec 2, 2020 15:22:37 GMT -5 frets said:

Hey Unreg,
I completely understand wired up jungles in a cavity🌿🌿
So don’t worry about the pic. I was interested when you spoke of several resistors on a pot. We all know here how to reduce a pot’s resistance using a resistor in parallel on lugs one and three; but, it sounded like a knowledgeable guru had augmented your system with more resistors on pots than just the resistance reduction described above. So forget my request. Let us know if you’ve got the hum fixed, I’ve not read that you have. Take Care⛄️⛄️.

Thank you frets. You take care too☃️☃️☀️.


(A pic of my old resistors, the only ones I have installed, on my tone pot from the post mentioned a bit above. Installed a new set bc I made the mistake of snipping off the ends of the first pair - that snipping off their ends caused the tone to change in a negative way for me.)

[frets]

Yep Unreg,
You’re dropping that 500k pot down to 250k. Makes it less bright.

You guys have probably established this and I was as usual, around the block and down the street.

[unreg]

Dec 2, 2020 17:49:53 GMT -5 frets said:

Yep Unreg,
You’re dropping that 500k pot down to 250k. Makes it less bright.

You guys have probably established this and I was as usual, around the block and down the street.

😂... you just established this. I had no idea. 🙂


So, if I would replace my 500K tone pot with a 250K tone pot, without the resistors, would that give the same tone? Hmmm... but bubbalou88 said,

“This reduces treble by loading the pickup more. While this does work it is doing so at the expense of allowing the full tonal output of the pickup.”

So, the resistors with a 500K pot cause “full tonal output” of my pickups, while maybe a resistorless 250K pot wouldn’t? I love my current tone and don’t have plans to replace the pot again now; am just curious.

[ashcatlt]

250K is 250K and it doesn’t really matter how you get there. Those resistors ARE altering the taper of that pot’s action, so switching to a 250K pot without the resistors would change where on the pot you might find a given “in-between” tone, but it will not change the tone at 10 or at 0.

[frets]

Hey Unreg,
250K Tone Pots will send more high frequencies to ground and that makes the sound from the guitar a little bit darker.
So the buddy who advised you to put the two 1 meg resistors on your once 500k tone pot was getting you to that 250k. But Ash is right, resistors on pots change the taper. Nonetheless, you like your tone so you must like the taper so if it ain’t broke....⛄️☀️!!

[ashcatlt]

Dec 3, 2020 17:25:36 GMT -5 frets said:

250K Tone Pots will send more high frequencies to ground...

Well, no... The parallel load is the bottom half of a voltage divider whose top half is the pickup. The impedance of the pickup gets bigger at higher frequencies, so that proportionally more of the high frequencies (compared to lower) are dropped across the pickup and therefor less is dropped across ("sensed by") the load. Reducing the bottom resistor makes that divider ratio get smaller at lower frequencies.

Nothing is actually "sent to ground". It either completes the circuit or doesn't, and in a lot of ways we can say that it is much harder for high frequencies to do that, because they see a higher total impedance on the way around. But the important part here is the frequency dependent voltage division.