tailor the way your pickup sounds/add many sounds cheap!

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moltenmetalburn

moltenmetalburn

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I posted this in another thread but thought i would be seen by more people as its own.


All this pickup installation talk has me wanting to share this information I found a while back by Helmuth Lemme on how to make a very cool tone device to shape the sound of your pickups. He wrote a German book on guitar electronics.

I figured just making it an easy to follow project would be cool.

buying new pickups is not the least expensive way to get a different sound out of your pickup. You can just tailor your current pickup to your liking or make many choices available.

changing the external load is. this replaces a standard tone control OR after experimenting one favorite value could be chosen. You can also leave one cap out so that position is your original pickup sound.

Change the external load of the pickup by using a rotary switch and capacitors to add different amounts of capacitance across the pickup. This shifts the resonant peak of the pickup around which is responsible for the bulk of a pickups voicing. many of you Im sure have heard heard of the varitone which is similar and you may also know of the seymour duncan pickup booster which has a pickup resonance switch based on the same principles.

The resonant peak is the frequency that has the highest output level. Practically no magnetic pickup has a flat frequency response and it's the frequency peaks & valley's that give pickups their individual "character".



All quotes by Helmuth E. W. Lemme

"This method is inexpensive but can be very effective. With only a little expense for electronic components, the sound can be shaped within wide limits. Standard tone controls lower the resonant frequency by connecting a capacitor in parallel with the pickup (usually through a variable resistor to give some control over how much the capacitor affects the pickup). This will give you much more sound variation than a standard tone control."
Click to expand...

Changing the frequency response with
different external capacitors parallel to a pickup coil




To backtrack a little and explain more about the resonant peak of a pickup:



The fundamental frequency response of a magnetic pickup.
Position and height of the peak vary from type to type



If you know the resonant frequency and height of the resonant peak, you know about 90 percent of a pickup's transfer characteristics; these two parameters are the key to the "secret" of a pickup's sound (some other effects cannot be described using this model, but their influence is less important).

What all this means is that overtones in the range around the resonant frequency are amplified, overtones above the resonant frequency are progressively reduced, and the fundamental vibration and the overtones far below the resonant frequency are reproduced without alteration.


How Resonance Affects Sound

The resonant frequency of most available pickups in combination with normal guitar cables lies between 2,000 and 5,000 Hz. This is the range where the human ear has its highest sensitivity. A quick subjective correlation of frequency to sound is that at 2,000 Hz the sound is warm and mellow, at 3,000 Hz brilliant or present, at 4,000 Hz piercing, and at 5,000 Hz or more brittle and thin. The sound also depends on the height of the peak, of course. A high peak produces a powerful, characteristic sound; a low peak produces a weaker sound, especially with solid body guitars that have no acoustic body resonance. The height of the peak of most available pickups ranges between 1 and 4 (0 to 12 dB), it is dependent on the magnetic material in the coil, on the external resistive load , and on the metal case (without casing it is higher; many guitarists prefer this).

The resonant frequency depends on both the inductance L (with most available pickups, between 1 and 10 Henries) and the capacitance C. C is the sum of the winding capacitance of the coil (usually about 80 - 200 pF) and the cable capacitance (about 300 - 1,000 pF). Since different guitar cables have different amounts of capacitance, it is clear that using different guitar cables with an unbuffered pickup will change the resonant frequency and hence the overall sound.
Click to expand...

So all of the science aside there are only a few parts you'll need:

1. A rotary switch

I sourced one here:

http://www.parts-express.com/pe/showdet ... er=023-666

2 pole 6 position. shorting so it makes contact before breaking to avoid popping sounds. you only wind up using half of the lugs on the bottom.

Dano from Beavis Audio research made a diagram of the switch and how it works. the A or red side will be used and the B or green left unused.



Dano from Beavis Audio Research made a diagram to explain the rotary capacitor selector. In the diagram where the two wires enter the circuit board you would wire one wire to each side of the output jack so the capacitors are placed across the signal to ground.





The smallest lowest voltage caps are best for obvious size reasons. the the recommended range is 470 pF to 10 nF. that range is 30 capacitor values from 470pf to 10nf so a good starting point would be every five values which would loosely be as follows:


2. Capacitors:

470pf = .00047mF

800pf = .0008mF

1.8nf = .0018mF

3nf = .003mF

5.6nf = .0056mF

10nf= .01mF

Ive sourced these which are approximate values to make it easy for you :

470pf, 820pf, .0018mf, .0033mf, .0056mf, :

http://www.smallbearelec.com/Detail.bok?no=162

.01mf:
http://www.smallbearelec.com/Detail.bok?no=888



you could even go so far as to choose cap type for each setting. for instance the higher peak settings could be paper in oil to sweeten the highs and the lower resonant settings could be metal film for clear bass. have fun searching for values though.

The grand total is about $4.90 plus shipping! Have fun hacking up your guitar at your own risk!

:thumbsup:
 
I've got a guitar with the guts spilled out right now, I'm thinking about doing this. You ever tried it? I'm just curious on whether it's worth it or not.
 
Motorpud":2utya63j said:
I've got a guitar with the guts spilled out right now, I'm thinking about doing this. You ever tried it? I'm just curious on whether it's worth it or not.
Click to expand...

I haven't ever done it this way with a bunch of choices on a rotary, I have used capacitors to tailor the sounds of my guitars for a long time though. occasionally on a switch for on/off operation.

This is a bit more adventurous but also yields more variability. you could just try some caps from signal to ground across each pickup soldering in favorite choices for each pickup if you're more of a set and forget type guy.
 
Rather than adjust the resonance, wouldn't this just cut highs like a long cable would? All this does is show the pickup capacitance. In order to adjust resonance, resistance needs to be shown as well, like in a tone pot. As far as my understanding goes.
 
JakeAC5253":3q69s9cu said:
Rather than adjust the resonance, wouldn't this just cut highs like a long cable would? All this does is show the pickup capacitance. In order to adjust resonance, resistance needs to be shown as well, like in a tone pot. As far as my understanding goes.
Click to expand...

an external variable resistor would give you control over how much capacitance is added.

I believe the resistance of the pickup itself comes into play here:




The Pickup as Circuit

From an electrical standpoint, a magnetic guitar pickup is equivalent to the circuit in Fig. 1.

Fig. 1. Electrical equivalent circuit of a magnetic pickup


A real coil can be described electrically as an ideal inductance L in series with an Ohmic resistance R, and parallel to both a winding capacitance C. This replacement circuit can be used as a first approximation. It is a bit simplified compared to the reality but quite useful for the beginning. The finer details are explained later. For a humbucker, two of these circuits have to be connected in series. Since both coils (with precise manufacturing) have practically identical properties, you may use the same simple replacement circuit for the electrical examination. You then have to use twice the values for the inductance and the resistance and half of the value for the capacitance as compared to one coil.

Many people measure only the resistance and think they know something about a pickup. But this is a fundamental error. By far the most important quantity is the inductance, measured in Henries. It depends on the number of turns, the magnetic material in the coil, the winding density and the overall geometry of the coil. The resistance and the capacitance don´t have much influence and can be neglected in a first approximation.

When the strings are moving, an AC voltage is induced in the coil. So the pickup acts like an AC source with some attached electric components (Fig. 2).

Fig. 2. A pickup as an audio voltage source plus second-order lowpass


The external load consists of resistance (the volume and tone potentiometer in the guitar, and any resistance to ground at the amplifier input) and capacitance (due to the capacitance between the hot lead and shield in the guitar cable). The cable capacitance is significant and must not be neglected. This arrangement of passive components forms a so-called second-order low-pass filter (Fig. 3).




Thus, like any other similar filter, it has a cut-off frequency fg; this is where the response is down 3 dB (which means half power). Above fg, the response rolls off at a 12 dB per octave rate, and far below fg, the attenuation is zero. There is no low frequency rolloff; however, a little bit below fg there is an electrical resonance between the inductance of the pickup coil and the capacitance of the guitar cable. This frequency, called fmax, exhibits an amplitude peak. The passive low-pass filter works as a voltage amplifier here (but doesn't amplify power because the output current becomes correspondingly low, as with a transformer). Fig. 4 shows the typical contour of a pickup's frequency response.
 
anyone ever try this, I was again experimenting the other day with good results.
 
yes.....i've put a multitude of different caps on a varitone, soldered it in to a few of my guitars circuits, and changed it on the fly.....on les pauls, the standard tone cap was around .203uf ceramic cap or 220nf but when i measure them on my crappy 15$ cap tester, they're all around 150-180nf...and they actually sound the best to me, even after testing the others in 2 of my guitars. so i kept the stock ones in there after much deliberating. i plan to maybe mess with some push/pull cap ratings for the tone knob (discussed below) in my les pauls.

anyways cap values used were:

*.01uf or 10nf ..nearly renders the 300k tone knob useless around 3 or 4..total mud, and is too open on everything above 3 or 4. not very transitional...almost more "mud" on/off (completely open).

*.05uf or 50nf almost the same as above, but tone knob starts to clamp a bit acceptably, not muddy. still pretty blah sounding in comparison to all the others above it.

*.100uf or 100nf in this setting, with tone all the way on 10, it sound like.....imagine your les paul stock tone setup, with your tone knob in the sweet spot to get that vocal like quality "half" turned down or even around 3-4 setting with a stock 220 cap. almost like a notched wah sound, but not as balls out wah-ish. this probably explains why i like the 180caps that are in my guitars....they just sound right to me, a tad rolled off.

*.220uf or 220nf to me, this is the right setting for a les paul for most people. it gives the most range with the tone pot...we all know how this sounds when you start turning down the tone knob. pretty versatile. perfect mix of clamping highs smoothly enough on the lower end, some vocal qualities in the middle range, and, but not muddy and open on the tone knob 10 setting, or completely turned "up".

*.450uf or 450nf tone knob clamps highs, but not too many highs, even on 0, but it still sounds good, just not optimal.

*.760uf or 760nf have to hear it to undertstand it....interesting though. really open, not enough cut for my taste at all.

once you settle on which caps you like, the options are really limitless with what you can do. you could put 2 different caps on a push pull tone knob, and run them say, stock, and a 100 or 130nf for a more notched sound without having to fiddle with the tone knob to get that sweet spot, once you isolate exactly what rating gets you that in your particular guitar.


all in all, i think it showed me what i wanted to hear. a lot of it is also so variable dependent from one guitar (pickups, picks, strings, technique, etc) and player to another, that i'd hardly say this would transfer well to everyone else BUT it could be used as a sort of baseline.

for me it worked well, cause ....a lot of my guitars are the same, so i know what i like, and what i was looking for, which, to me, is half the battle...either way, i'd highly recommend anyone try this that would be looking to broaden their tonal knowledge regarding their own guitars....

after i figure out exactly how i want to do the push pull tone knob, my next project with a varitone will be treble bleed on the volume knob....figuring out what settings are best for each guitar i have to achieve the results i want. my ibanezes seem to like 470pf, and my les pauls seem to like 520pf or so to achieve the results i want when rolling the volume back...but i've only messed with 1 of each of them.

silver mica, orange drop, ceramic, etc.....now you're just getting into splitting hairs. the stock ceramics sound fine to me, as i said...
i like silver mica if im going to buy new, specific ratings, and i have some orange drops lying around that i can use, cause thats what i have lying around lol.
 
thanks man! i had to go back and check my notes and clarify some stuff...


this is a great thread. i only recently actually did this, about a month or so ago...but always wanted to.
 
I'm a fan of the Tonestyler but you couldn't do this with one. Unlike the rotary switch the Tonestyler doesn't have an 'in and out' as it just operates as a tone control does - with one wire. Would be cool if it would work with one as they are nice and compact.
 
Actually tone styler is available in notched or smooth rotation formats.

both are insanely overpriced. :thumbsdown:

Edit: just tread they simplified the line and no longer offer the smooth rotation as of 2012 .
 
moltenmetalburn":2h1ys29m said:
Actually tone styler is available in notched or smooth rotation formats.

both are insanely overpriced. :thumbsdown:

Edit: just tread they simplified the line and no longer offer the smooth rotation as of 2012 .
Click to expand...


You want the notched one anyway. I agree they are overpriced, but many things are when it comes to guitars and parts (boutique pickups and Gibsons come to mind). I got mine for a good deal and they work perfectly for my needs on my Tele. They do exactly what the company says they do. No more, no less. Whether it's worth the cash for you is your call. It was for me. Kinda feel the same way about the Super Vee Blade runner I have.

The reason I say the Tonestyler wouldn't work is it is only a one wire hook up. You need to run out of the pickup, into the varitone, and back out to the pickup. You can't do that with the Tonestyler. Hot and ground is all you have.

I am diggin' this whole concept and may mess with this with my Les Paul prior to changing pickups. i don't mind hardwiring in a cap if it sounds good.
 
i put a varitone in my tourmaster amp LOL. 7 different resistors wired in one of the fixed gain resistor slots. which, gave it the option of a tighter gain structure in the higher ratings, or more loose, wilder gain structure down on the low end. i love it, and am actually going to install it permanently very soon. it's actually really wild when you start doing this stuff, and see how many options there are out there regarding things you can do in/with an amp.
 
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