"De-Mud Mod"
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beaubrummels
Well-known member
What is the practical difference between a 500k and 0.01uf in parallel with eachother versus just using a 0.047uf?
I've looked at all the threads I can find on the subject but they all seem to just be a bunch of wannabe electrical engineers who misunderstood the original post
Also one point of disagreement I see on the threads. Is the effect subtle or not?
Also whats the cleanest way to do the install if I only have 2 conductors on my neck pickup? I've always been bad at twisting a cap and resistor into parallel
I've looked at all the threads I can find on the subject but they all seem to just be a bunch of wannabe electrical engineers who misunderstood the original post
Also one point of disagreement I see on the threads. Is the effect subtle or not?
Also whats the cleanest way to do the install if I only have 2 conductors on my neck pickup? I've always been bad at twisting a cap and resistor into parallel
beaubrummels
Well-known member
I thought I read in one of the thread what the difference is, they even posted a graph showing more roll off with just a cap.
I haven't bothered with it, so I can't speak to whether it's subtle or not. The original guy who came up with the mod said it was subtle, so I would tend to believe his word. But jus try it with aligator clips to test it before soldering and see for yourself. Pretty easy to figure out.
This graphic from the first thread shows how to do it with 2 conductor.
I haven't bothered with it, so I can't speak to whether it's subtle or not. The original guy who came up with the mod said it was subtle, so I would tend to believe his word. But jus try it with aligator clips to test it before soldering and see for yourself. Pretty easy to figure out.
This graphic from the first thread shows how to do it with 2 conductor.
freefrog
Well-known member
1)Obviously, a 500k resistor in parallel with the series cap would simply make it cut less bass.
2) The effect is subtle or not depending on other parameters. A series cap has simply not the same action with a 470k input impedance than with a 1M input impedance, for example. And a series cap doesn't behave in the same way before or after a volume control.
3)Wire your neck pickup to its regular tone control. Then go through a series cap from the tone pot to the volume control. It will avoid any conflict between bass-cut/hi-pass and hi-cut/low-pass circuits.
EDIT - A good demo is better than words. Below is a topic about the PTB circuit, whose bass-cut/hi-pass part involves a series cap + a variable parallel resistor (the 1M pot). Note how the regular hi-cut/low-pass regular tone control has been wired before the other part of the circuit, in order to make them cooperate nicely...
https://tonefiend.com/guitar/two-ban...cheap-awesome/
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This graphic from the first thread shows how to do it with 2 conductor.
I saw that image too, I meant whats the easiest way to implement that wiring. This is in a Les Paul style guitar, so I have a three way toggle switch, a master volume and master tone. Soldering directly to the pickup wire seems like it would be a strange implementation.
As I forgot to mention earlier, I have a master volume and master tone control, so I guess I have to put the de-mud portion before the tone control. How will this conflict look in terms of when I'm actually playing?
beaubrummels
Well-known member
Same as the Duncan image shows; if you have two pickups on a switch then going to the master volume/tone, then you wire it between the neck pickup and the switch. If you only have one pickup, then use the diagram on the bottom with the volume, and wire it between the pickup and the volume. Master tone shouldn't be between the volume and the jack, it should tap off the volume in between the volume and the jack. So you would not wire it between the volume and the tone. The de-mud mod is for the pickup, so it needs to be wired off the pickup before any other components. Not sure what you mean by a conflict while playing.
freefrog
Well-known member
With a series cap before it, a tone control tends to behave like a second volume pot. That's how I spot humbuckers (or single coils) that a broken coil wire made capacitive, for the record (and that's something that anybody can check personally in a few minutes with a capacitor + a pair of alligator clips, BTW).
Hence the clever trick popularized by ArtieToo and consisting to put the series cap between coils: it diminishes a bit the downside that I describe. Now and IME / IMHO, a tone pot before the series cap remains the simplest way to make hi-pass and low-pass filter working nicely with each other, without any change in how the tone pot works. YMMV.
EDIT - That said, there's an alternative solution: using a Fender TBX pot with the (no load) 250k side wired as a regular tone control and the 1M side as a master "bass cut" with a series cap. The two tone controls can't be in conflict with such a pot, since it allows to use low-pass/hi-cut OR low-cut/hi-pass and not the two circuits altogether...
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Interesting. So to make the effect more pronounced I decrease the value of the cap. If i understand it, a smaller cap increases the bandwidth of bass being cut? How does the resistor value change things?
I'm not sure I'll need to change the values too much, though. It's not a massive amount of bass I'm trying to get rid of.
I'm not sure I'll need to change the values too much, though. It's not a massive amount of bass I'm trying to get rid of.
BlackhawkRise
Active member
Doesn't this sort of thing mess up old school fuzz pedals?
freefrog
Well-known member
Yep, the smaller the series cap, the more bass it cuts... but the "corner frequency" changes according to the whole circuit involved (from guitar to FX or amp).
Yes, a series cap has a "weird" effect on Fuzz Faces. Below is a 5Spice sim about that (red line = the response of a pickup + a FF without series cap and other lines = the effect of a series cap, increasing while the 1M pot of a PTB control is progressively turned).
Regarding the effect of a 500k resistor // to the series cap, here is another 5Spice sim. The red line shows the effect of the cap without parallel resistor...
And finally, here is the response of various pickups with a tone pot @ 0/10 (orange or pink lines) VS their response with the same pot @ 0/10 but after a series cap (response translated in each case by the darker line, with a clear volume drop). Left upper pic= 5spice simulation. Wide bottom pic = electrically induced resonance of another pickup in the same situation. Right upper pic = a last iteration of the same thing, with a last pickup in a guitar played direct to the board.
Yes, a series cap has a "weird" effect on Fuzz Faces. Below is a 5Spice sim about that (red line = the response of a pickup + a FF without series cap and other lines = the effect of a series cap, increasing while the 1M pot of a PTB control is progressively turned).
Regarding the effect of a 500k resistor // to the series cap, here is another 5Spice sim. The red line shows the effect of the cap without parallel resistor...
And finally, here is the response of various pickups with a tone pot @ 0/10 (orange or pink lines) VS their response with the same pot @ 0/10 but after a series cap (response translated in each case by the darker line, with a clear volume drop). Left upper pic= 5spice simulation. Wide bottom pic = electrically induced resonance of another pickup in the same situation. Right upper pic = a last iteration of the same thing, with a last pickup in a guitar played direct to the board.
Artie
Peaveyologist
freefrog
Well-known member
Well, a cap in series with a pickup works like a coupling cap in an amp or FX: the smaller is the capacitive value, the more bass it cuts...
I share below another 5Spice sim about such things. Red line = no series cap. The other lines show how the response of a pickup is altered by series caps from 15nF to 4.7nF (the 15nF being the one cutting the less bass).
I have "real life measurements" showing the same kind of things and that I might share later but it's late at night here in Europe and I must go to bed now...
See you later, gentlemen. ;-)
I share below another 5Spice sim about such things. Red line = no series cap. The other lines show how the response of a pickup is altered by series caps from 15nF to 4.7nF (the 15nF being the one cutting the less bass).
I have "real life measurements" showing the same kind of things and that I might share later but it's late at night here in Europe and I must go to bed now...
See you later, gentlemen. ;-)
Chistopher
malapterurus electricus tonewood instigator
Artie
Peaveyologist
Chistopher
malapterurus electricus tonewood instigator
freefrog
Well-known member
Yes, the action of series caps depends on the circuit.
For instance, with a series capacitor between pickup and tone pot, here is what happens: once the tone pot is @ zero (IOW: shorted, with zero resistance), the series cap is itself in series with the tone cap to ground . With a 10nF series cap and a 22nF tone cap, it's as if the tone cap was now a 6.8nF one ( = 1/ [1/10 + 1/22]) ...
It doesn't happen when the tone pot comes first: in this case, the 22nF to ground logically sets the resonant peak around 500hz once the tone pot is @ 0/10. Then the series cap tightens the bassrange of this remaining signal exactly as it would do when the tone control is full up.
This is an attempt of explanation in readable terms and it doesn't cover all the effects of such circuits but "you get the picture"...
Post scriptum - I've many other experimental data about all that in my archives but I lack of free time to convert them in publishable pics and honestly, I can't put online for free all of my work for a local winder. Now, if I can help, I'll gladly do it so feel free to PM me.
For instance, with a series capacitor between pickup and tone pot, here is what happens: once the tone pot is @ zero (IOW: shorted, with zero resistance), the series cap is itself in series with the tone cap to ground . With a 10nF series cap and a 22nF tone cap, it's as if the tone cap was now a 6.8nF one ( = 1/ [1/10 + 1/22]) ...
It doesn't happen when the tone pot comes first: in this case, the 22nF to ground logically sets the resonant peak around 500hz once the tone pot is @ 0/10. Then the series cap tightens the bassrange of this remaining signal exactly as it would do when the tone control is full up.
This is an attempt of explanation in readable terms and it doesn't cover all the effects of such circuits but "you get the picture"...
Post scriptum - I've many other experimental data about all that in my archives but I lack of free time to convert them in publishable pics and honestly, I can't put online for free all of my work for a local winder. Now, if I can help, I'll gladly do it so feel free to PM me.
