HSS strat tone pot mystery (to me)

[Deleted]

I bought an inexpensive HSS strat the had tone1 wired to the neck pu and tone2 wired to the middle pu. I decided to learn hands on about guitar wiring and wire tone2 to the bridge/humbucker and tone 1 for both neck and middle. That was fairly easy, but all three pots are 250k and each tone pot has a wired .047 cap on it. That works OK for the single coils but the combination seemed restrictive on the humbucker. So, I thought lets remove the cap on tone2 for the humbucker. My logic (ignorance) was less resistance = more tone for the humbucker. After removing the cap, the tone control for the humbucker did absolutely nothing. I soldered it back onto tone2 and it's working again. So does this mean that the pot is not working? Or, have I misunderstood how this all plays together? I'm trying to understand all this. 
Thanks

[JohnH]

Hi @thunderroad and welcome to GN2

The usual tone circuits on guitars work by the pot joined end-to-end in series with the cap. This bleeds some treble to ground, reducing the brightness, through the cap and controlled by the pot. So if you remove the cap, the whole thing becomes ineffective.

I like HSS guitars, I think they can be a perfect mixture of tones. There's no right or wrong way to wire them (so long as it works!), but there's always a choice between keeping the brightness in the thick-toned humbucker, vs taming the treble of the singles.

I quite like using no-load pots for treble, that cut out at 10. If you tried without the cap with your bridge tone, apart from the fact thst the pot didn't work, what did you think of the slightly brighter tone? There are ways to have that with no-load pots and still have tone control.

[Deleted]

Thank you.
I think I understand. So, when one lead of the cap is soldered onto one of the lugs of the pot, and the other lead is grounded to the case of the pot, is that considered "in series?" I thought the pot itself could bleed off treble, but you are saying that it's the cap the does it, with variability of the pot. Correct?

I liked the uncapped sound of the humbucker, but it wasn't a huge difference from with the cap. I will look into the no load pot, as it seems like something I could like. With a humbucker, do you use a 500k no load pot?

[JohnH]

That sounds right. So it's a one-lane path from volume pot through the tone pot , through the tone cap, to ground. Break the path anywhere eg by removing the cap and no treble can bleed away. The no-load pot does this by breaking the circuit as the pot gets to 10, then below 10 its like a normal pot.

My HSS has a single master tone pot which is 250k no-load, and I also have some interesting blending features using what was the second tone pot. I have a 250k volume pot. I find that the 250k no-load is fine, and it gives the full bright disconnected no-load sound the same as a 500k no-load would. As it goes from no load to 250k, it's a very small tone step so I don't feel I need to subdivide it with a 500k. If you found with your cap/no-cap test that it was just a small (but useful) step, then you might conclude the same.

[kitwn]

Thunderoad,

Welcome aboard, you're in the right place if you want to experiment with guitar electrics.

If you're so new to the subject that you're not even sure what 'series' means then I strongly advise you to learn a few basics of electrical/electronic circuit theory before you start wielding the soldering iron. A quick search for electronics 101 brought up a pile of links including the YT video linked below. I haven't watched the whole thing but it looks like a good enough place to start.

Having some basic knowledge in your head will help you understand what you want to do and why. A few hours study will save you many hours of fruitless experimenting inside your guitar and possibly save some components being damaged by the repeated heating from a more experimental approach. If you watch/read something you need clarification on then there are plenty of willing helpers on this forum.

Learning some basic electronics will not give you all the answers to the ultimate guitar tone, but it will help you to work out the right questions.

Kit

[Deleted]

Thanks Kit,
I do have a very basic understanding, but I don't quite understand how the tone pot works in the signal circuit. Let me use the image below as I understand it. The input signal from the pickup, via the switch, goes the the input lug (sweeper) of the tone pot. This will control how much of the signal is sent to the cap, which filters some of the signal to ground. The tone pot is grounded to the volume pot which closes the circuit. I don't understand that there is no output from the tone pot. Is it that the tone pot in play because it "grabs" the signal via the common on the 5-way switch?

[sumgai]

thunderroad,


Hi, and to The NutzHouse!


Essentially, the best way to look at the bog-standard tone pot is to call it by its correct name, a treble cut. Some of your response just previous is correct, and some is, err, a little off-course. Which is which, doesn't matter. The fact is, basic electronics tells us that a capacitor wants to pass through higher frequencies, and reject the passage of lower frequencies. The point where the 'switch-over' occurs is dependent on the cap's value. Hint: it's a gentle curve between the two regions, not a sharp corner.

What a guitar does is place a cap between the pickup and ground. Given what I just said, we now know that the cap will conduct some of the signal, meaning the higher frequencies, straight to ground. That's all well and good to say, but now you're asking, what does that mean for the final tone that comes out of our axe?

Well, it means that electricity will always seek the easiest path back to the source. In this case, the source is our pickup, and we use the term "ground" to indicate a common point where several signals might be attempting to return to the source. Hint: that 'return to source' is usually denoted on the pickup by the negative symbol, or the minus symbol, take your choice.

Since the higher frequencies that got through the cap have already been returned to the source (via ground), there's nothing left to travel further on towards the output jack, and thence on to the amp (or pedals). This describes the action of "cutting the treble frequencies", they're no longer available for us to work hear.

That's the very basic way that the guitar's tone control has been working since the 1930's, and still how it works today.  All that's left to say is something about the variable resistor, or the Tone Control itself.  This works not on the frequencies themselves, but on the level of the signal passing through.  The higher the resistance, the smaller the overall signal is fed to the cap, and thus the smaller amount of 'cut' that we notice.  As we twist the control further (usually counterclockwise), the resistance becomes less and less, and that means that a greater level of the signal gets through to the cap.  From there, it should now be obvious that we can vary the overall tone of the guitar from sharp and clear to muddy and/or muffled, simply by rotating the tone control, or the treble-cut control.
 
You have other questions, but this was your first and foremost (in my judgment). Let's make sure that you've got the concept down, even if you don't know exactly how a capacitor works at this point in time.  I've also not looked at the linked video above, but if kitwn says it looks like a good place to start, then I'll go along with him on that score. One final thought on that learning bit..... take it easy, don't force it.  None of us here was born knowing all this stuff, we had learn it from other folks, just like you will, here in The NutzHouse.  The real key is curiosity.  You're gonna fly off in several (many!) directions, and that's not just OK, that's great.  We'll keep you focused when and where you need to concentrate, and we'll let you blather all over the place when that's needful too.   

Your final take-away from all this is to have fun!

HTH






sumgai