Alternative wiring for a brighter neck pickup

[vincenz]

I started up with this reflexion:
I need a tone control to reduce treble on the bridge pickup, indeed, but what I really need on the neck pickup is a tone control to reduce bass.
In addition, I wanted to solve definitely the problem of treble loss when lowering the neck pickup volume.

I am used to play some dynamic single channel amps (Trainwreck clones and Reinhardt Sultan) and I manage all sound changes from the controls of the guitar. I like to play main riffs and leads with the bridge pickup at full volume, I switch to the neck pickup with the volume rolled down in order to clean up the things.
I am trying out some different component values with this wiring for a couple of month and now I am fully satisfy with this set up.


The bridge pickup section is wired in a classic way, '50 style, however with these distinctive features:
Volume control: I finally found the best volume pot for me. I tried the RS superpot, Dr Vintage, even the expensive Alessandro, all of these are great products. Then I bought the CTS "True Vintage Taper" (TVT) from crazyparts.de, value slightly above 500k and the perfect taper for me.
Tone control: 500k linear pot and Luxe .022uF cap.

The neck pickup wiring is more specific:
Volume control: 1Meg audio pot with a treble bleed circuit (.001uF cap and serial 230k resistance). I am using a 1Meg pot instead of the conventional 500k for these two reasons:
First, to increase the resonant peak, so the neck pickup sounds brighter and clearer at full volume.
Secondly, to improve the curve of the pot with the treble bleed.
Tone control: 1Meg linear pot and "bass-cut" special circuit with .001uF cap and grounded 1Meg resistance.

Here is the diagram :

 

[HOT-BRIT]

interesting

 

[cochrane]

Definitely. I've been looking into trying to get a cleaner neck pup signal myself recently (had got as far as ordering a 1M vol pot), and this doesn't look like an expensive thing to try. (My search for a longshaft linear 1M push-pull pot for the tone control hasn't borne fruit so far, unfortunately - might have to abandon my switching option.)

Lovely neat diagram too!

 

[David Collins]

Very cool that you got it working how you like. There are a few things I'm trying to make sense of here though.

First and foremost is the linear pot for the bridge tone control. Do you use that tone control much, and if so do you specifically prefer 90% of the effective adjustment in the bottom 20%? I've heard of a few people that actually do like this, but not many.

Second, I'm not clear on a few things with the bass cut. The 230kΩ resistor in series with the .001μf cap is a bit unique. I've done similar layouts on occasion and can see the sense in it, but it's probably less common than running them parallel. It especially seems a peculiar choice to have them run this way in this arrangement though, where the signal is always routed through the kit.

I would have been inclined however to run that treble bleed kit directly across the upper volume lugs. Then I would typically run the pickup straight to the tone pot (bass cut pot) center, then tone pot upper lug back to volume pot coil lug, and a 220nf-680nf cap across those tone pot lugs, then center volume lug straight to the switch. This way you would always at least have the option of using the neck pickup in its full form with the bass cut on 10 rather than with a permanent bass cut as it's wired now. This would also leave you with a bit more volume overall while still effectively cutting the bass when turned down. And a linear pot can work fine for this usage, though I've not tried it with exactly the layout have pictured.

I'm also curious how it responds in the middle switch position with the neck volume on zero and bridge volume on 10.

And finally, I'm a bit mystified by the 1megΩ resistor to ground on the bass cut pot, as it would seem any extra loading of the neck pickup would be counter to your objective of favoring trebles against the bass.

 

[vincenz]

I am not an electronic master, therefore I did a lot of "real" experimentations instead of theoretical calculation and schematic...

In this case there are two distinct parts (which can be totally separate if needed):
1: the .001μf cap and 230kΩ res in series for the treble bleed. Disastrous if wired in parallel in this configuration (I do not know why, it just works fine like this). It is soldered to the tone pot lug only to have a nice layout, but of course the result would be the same if attached to the volume pot lug.
2: the bass-cut "tone" control, which needs the 1M grounded res to work. Furthermore, if this "tone" pot is set to 10 the bass-cut circuit is totally bypassed. Thus with vol and tone at 10, the only difference with a standard wiring is the resonant peak affected by the 1Meg pots.

 

[jonesy]

You could have just wired an .015-.010 capacitor in series between the neck pickup lead and the outside lug on the volume pot and left the 500k pots and the rest of the wiring the same. The cap in series on the pickup lead would have cut some of the unwanted lows and also changed the resonant peak frequency of your neck pickup giving you more clarity.

 

[vincenz]

You could have just wired an .015-.010 capacitor in series between the neck pickup lead and the outside lug on the volume pot and left the 500k pots and the rest of the wiring the same. The cap in series on the pickup lead would have cut some of the unwanted lows and also changed the resonant peak frequency of your neck pickup giving you more clarity.

Maybe, but the result would be neither a bass-cut control pot, nor a treble bleed behavior on the volume pot...

 

[jonesy]

Maybe, but the result would be neither a bass-cut control pot, nor a treble bleed behavior on the volume pot...

No not maybe...an .015-.010 cap in series with the neck pickup lead would have done exactly what I said. Cut the unwanted lows and shift the resonant peak frequency allowing more highs. And with 50's wiring you don't need a treble bleed circuit as 50's wiring retains the highs so treble bleeds are not needed. Then you would still have volume and tone controls that function normally. I guess I always try and go for the less is more type method of wiring when I can to still achieve the same end result. Adding all those caps, resistors and 1 M pots is just going to "color" your tone making it thin and brittle, that's just my 2 cents YMMV.

 

[vincenz]

Yep, I don't doubt about what you said, I know your skill and experience, and I learned a lot from your posts and your website (many thanks for that, by the way )...
Maybe I am doing something wrong, or maybe I am expecting to much of my Les Paul, but for me the 50's wiring does not do the trick. Indeed it is much better than the standard wiring style, but it still loses too much treble when rolling down the volume. That's why I did choose the less smart but more radial treble bleed solution...
Actually, I never tried the .015-.010 cap in series with the pickup lead. But I will do it on my other '50 style wired Les Paul asap

 

[jonesy]

Yep, I don't doubt about what you said, I know your skill and experience, and I learned a lot from your posts and your website (many thanks for that, by the way )...
Maybe I am doing something wrong, or maybe I am expecting to much of my Les Paul, but for me the 50's wiring does not do the trick. Indeed it is much better than the standard wiring style, but it still loses too much treble when rolling down the volume. That's why I did choose the less smart but more radial treble bleed solution...
Actually, I never tried the .015-.010 cap in series with the pickup lead. But I will do it on my other '50 style wired Les Paul asap

Nothing wrong with tinkering and I commend you for that, that is the best way to learn. You could try anything from .022-.005 uf in series on that neck pickup lead for cutting the lows and allowing the highs to come through. It depends on the pickup and your personal tastes. You might try a pair of alligator clips and swap out a few caps until you get the right value that works for you. Once you do that you might also find that the treble bleeds are not needed. Happy Holidays to you and yours!

 

[David Collins]

I am not an electronic master, therefore I did a lot of "real" experimentations instead of theoretical calculation and schematic...

In this case there are two distinct parts (which can be totally separate if needed):
1: the .001μf cap and 230kΩ res in series for the treble bleed. Disastrous if wired in parallel in this configuration (I do not know why, it just works fine like this). It is soldered to the tone pot lug only to have a nice layout, but of course the result would be the same if attached to the volume pot lug.
2: the bass-cut "tone" control, which needs the 1M grounded res to work. Furthermore, if this "tone" pot is set to 10 the bass-cut circuit is totally bypassed. Thus with vol and tone at 10, the only difference with a standard wiring is the resonant peak affected by the 1Meg pots.

Ugh, I wasn't thinking through the whole circuit when I looked at it before - Obviously the pickup is fully engaged with the volume pot when the bass cut is full up. My mistake.

Other points though - I still don't see any need for the 1meg resistor there. It won't hurt, and maybe it could add a slight amount of effect by loading the coil and lowering the resonant frequency a bit more when on 10, but it may create an ever-so-slightly noticeable effect at best. The main part of the bass cut circuit is redirecting the signal through the cap though, and it certainly doesn't need to add any load across the coil or output to function.

There is still the issue of how the neck volume control would function in the middle switch position when the bass cut is rolled back. The effect may be cool (don't know, never tried it this way), but it will no longer act fully as a master volume. I still would lean toward keeping the center lug of the volume directly connected to the switch, and run the pickup through the bass roll off instead. I don't have programs to make the drawings you do, but here's the low down -

Switch to center volume lug, pickup to upper tone lug.
Center tone lug to upper volume lug.
Treble bleed cap/resistor across center and upper volume lugs.
Bass cut cap across center and upper tone lugs.

This would give you the same treble bleed when you roll the volume back with the bass cut full up, the same bass cut roll off when the volume is full up, but would change the way they work when both rolled back and keep the volume working as a master in the middle position. Of course maybe that's not what you want, but it would be the more normal layout of a bass cut circuit.

For the treble bleed, 220kΩ parallel with a .001μf cap has been a pretty common circuit for a few decades. It keeps the treble up, and alters the effective taper to be a bit closer to the standard Gibson linear volumes. Certainly not for everyone, but works for many. Your series arrangement will not alter the effective taper as much, but still put it somewhere between an audio and linear, and I can certainly see why you prefer it this way. Both arrangements seem to have different effects with different rigs and pickups, sometimes keeping the highs fairly constant, but also sometimes seeming to make it too brittle as you roll back. Lot's of ways to do it, all subject to personal taste.

As to value of the bass cut cap, I just don't find much of a noticeable effect until you get down below the .002μf range. I can't explain exactly why a cap in series with a pickup (bass cut) seems to respond to a completely different frequency range than one in parallel (standard tone), but it does. When I want to wire any kind of bass cut circuit, I usually start at .001μf and below, sometimes going down to the 220pf range. Don't ask me why it works that way, but it does. And if you want a full effect for a really thin almost out of phase tone, cut the ring to make the pot no-load at zero.

And I still don't get the linear bridge tone pot. I've heard of people claiming to like it, but all it really does is concentrate all the adjustment down to the very very bottom.

 

[cochrane]

While people are still looking at this thread, has there ever been much argument over whether or not the length/amount of wiring between each element of a guitar's electronics introduces tonally significant levels of capacitance, as per the length of cables from guitar to amp?

 

[David Collins]

While people are still looking at this thread, has there ever been much argument over whether or not the length/amount of wiring between each element of a guitar's electronics introduces tonally significant levels of capacitance, as per the length of cables from guitar to amp?

Oh yes, absolutely. Gibson Coaxial wire can run up around 75pf/ft, so every foot of coax in your guitar can amount to about 2' of your average cable. Resistance isn't remotely close enough to enter in to the equation, but the capacitance of cable and components can add up.

 

[Mookakian]

No not maybe...an .015-.010 cap in series with the neck pickup lead would have done exactly what I said. Cut the unwanted lows and shift the resonant peak frequency allowing more highs. And with 50's wiring you don't need a treble bleed circuit as 50's wiring retains the highs so treble bleeds are not needed. Then you would still have volume and tone controls that function normally. I guess I always try and go for the less is more type method of wiring when I can to still achieve the same end result. Adding all those caps, resistors and 1 M pots is just going to "color" your tone making it thin and brittle, that's just my 2 cents YMMV.

You know jonesy, i have been testing this out in many ways and i noticed something yesterday, the series mod has a massive effect when a fuzz is enguaged. With a .015 cap on an 8k neck bucker straight into an amp the tone is only slightly different as i hit the switch to activate the series cap mod... but throw a fuzz on and the switch makes a massive difference in wollyness. Have you noticed anything of this nature.


Sorry OP, on track with your set up...that is wild Nice to see some experimentation But i agree, its prob not too efficient and similar results can be had with far less complications, but dont let that stop the trialing, you may find somethin killer in the end \m/

 

[jonesy]

You know jonesy, i have been testing this out in many ways and i noticed something yesterday, the series mod has a massive effect when a fuzz is enguaged. With a .015 cap on an 8k neck bucker straight into an amp the tone is only slightly different as i hit the switch to activate the series cap mod... but throw a fuzz on and the switch makes a massive difference in wollyness. Have you noticed anything of this nature.

Yes Mook I have noticed the very exact same thing when using my Esquire with the rotary switch and a Fuzz pedal. The reason is the various caps in the rotary switch (or in series on the pickup) are directly in series with the in/out coupling caps in the Fuzz pedal so you get even a more dramatic shift in the peak frequency with all those caps in series.

 

[Mookakian]

Ah of course! Makes perfect sense

 

[vincenz]

ok Jonesy, I did the series cap test today on a equivalent guitar. Of course it cuts some bass, but only a few (with my solution it is possible to cut down a lot more bass). And unfortunately the brightness still disappears when volume is rolled down...
Therefore it does not do the trick for me

Well, how shall I say... I would recommend you to test my circuit to allow your ears to notice how much it is efficient.
*The resonant peak makes the neck pickup really singing at full volume, thanks to the 1Meg pots.
*The treble bleed does his job and allows to have a bright clean sound at low volume.
*The bass-cut pot from 9 to 7 cuts the unnecessary bass frequencies , and from 7 to 0 it changes the bass response in a more radical way.
@ David Collins: in the same time, you would also notice that the 1meg res to ground is essential (do not ask why, just believe your ears )

 

[jonesy]

What size cap did you use in series when you tried it on the neck pickup lead?

 

[vincenz]

.022 , .015 , .005

 

[jonesy]

The .005 should have made it sound like a bright single coil Tele pickup