Hum is now caused by treble. unreg?

[unreg]

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

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.

That extremely helpful guy provided just a list; he, thankfully, let me chose what to use. Read my explanation from earlier in this thread:

Nov 30, 2020 19:39:16 GMT -5 unreg said:

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.

—-
frets, thank you so much for helping me to know that the two 1 meg resistors reduce my 500K tone pot to 250K! It’s extremely fun to know some of the specifics behind my guitar electronics!

[unreg]

Dec 3, 2020 13:34:04 GMT -5 ashcatlt said:

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.

Dec 3, 2020 18:22:41 GMT -5 ashcatlt said:

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.

Very interesting; thank you ashcatlt!

[frets]

Thanks Ash,
No one has ever described it to me like that.

Unreg,
So where are you with that hum. Is everything good now?

[ashcatlt]

Dec 4, 2020 12:01:10 GMT -5 frets said:

Thanks Ash,
No one has ever described it to me like that.

I find it to be the most useful way to think about how a filter works. “Everything useful is a voltage divider”. Figure out what makes the top of the divider and what makes the bottom. Caps get big at low frequencies. Inductors get big at high frequencies. When you start mixing them, things can get complex (like literally complex as in imaginary numbers and vector math) which can lead to resonances and such, but for quick “back of envelope” eyeballing, it is a good way to get a general idea of what’s happening.

[blademaster2]

Dec 4, 2020 15:49:10 GMT -5 ashcatlt said:

Dec 4, 2020 12:01:10 GMT -5 frets said:

Thanks Ash,
No one has ever described it to me like that.

I find it to be the most useful way to think about how a filter works. “Everything useful is a voltage divider”. Figure out what makes the top of the divider and what makes the bottom. Caps get big at low frequencies. Inductors get big at high frequencies. When you start mixing them, things can get complex (like literally complex as in imaginary numbers and vector math) which can lead to resonances and such, but for quick “back of envelope” eyeballing, it is a good way to get a general idea of what’s happening.

That is a beautiful and simple way to look at it. I think of it that way myself.

[unreg]

Dec 4, 2020 12:01:10 GMT -5 frets said:

Unreg,
So where are you with that hum. Is everything good now?

Where am I with that buzz? Hmmm... last night, I tackled a problem that I rediscovered while looking at the wiring.

The problem: The signal wire from my bridge pickup, to my 3-way switch, is a size 30 wire and so VERY thin. I had resoldered that connection after creating the star ground paperclip, and maybe 5 of those strands were loose after the solder point was made... so had I wrapped that part of the exposed wire with electrical tape. That electrical tape did NOT hold and all the wire strands in that thin, size 30 wire, turned black.

The solution: So, I trimmed the black wire, restripped, and soldered the nice shiny bridge pu wire to my switch. However, before sleep, I noticed that my melting of that point’s solder on the iron’s tip caused the solder point to appear yellow. And after listening this morning, it sounded bad - the tone was restrained. So just finished removing that yellow solder and soldering that point again... correctly this time.


Now, the guitar’s tone is so full! But, a little of that buzz appears again after turning the vol knob to max. Not solved yet, but definitely much closer than I’ve ever been to a noiseless guitar. ☃️ I’ll keep you updated, but not here as this thread’s problem has already been solved.