David Schwab

The metallized polyester film capacitors from Radio Shack work fine for tone controls.

The whole thing about the tone of caps has more to do when using them as coupling caps where the signal is going through them.

For simple things like tone controls, polyester caps work fine, which is what orange drops are.

Good stuff there Mike. I am genuinely interested in what you are doing here. I still don't see where FEMM is all that useful in pickup design though since it only simulates the magnetic field. That's a small part of the whole.

Ah! I see! I like phase switches on guitars.

but anyway, i just love the off-phase sounds on my strat though, perfect for those funky rhythm riffs

If you mean the 2 and 4 positions... that's not out of phase. They are in phase, but the pickups are close together.

Out of phase is real thin and "snarky" sounding. Fender Mustangs have phase switches.

I'm toying with offering the set with each coil in its own cover, so that they can be used with wider string spacings, like on a fanned fret guitar.

Clint Searcy (searcy string works) makes pickups exactly like that.

The original Bartolini pickups had one coil per string, and Wal basses have two separate coils per string, forming a humbucker for each string.

I did it back in the 70's on my Ric bass. It's not very useful unless you want a REALLY thin tone with no bottom at all. If you turn one pickup down a little it brings the bottom back a bit.

Also running them series out of phase has a bit more lower mids, but that's really thin sounding too.

You need to run a separate line for each pickup to use it for MIDI. You can't run them to a 1/4" jack. Look at the jack used on the Roland units. You need something like that.

You also need a way to stop from having cross talk between strings, if you are using piezo pickups. Each pickup will need it's own preamp before it goes to the MIDI converter to convert the impedance. The MIDI unit is expecting very low impedance coils, not very high impedance piezo sensors.

Diodes wound clip (distort) the signal, and wont give you any isolation. You wont get an "ohm" (resistance) reading through a diode, and also you wont get a resistance reading on a piezo pickup either.

What you are trying to do is pretty complicated, especially if you are unfamiliar with electronics and piezo bridges. You'd be better off to buy a MIDI unit for a nylon guitar.

Thanks for the other HB link appreciated. Hopefully the buying winder explanation is not taken as a wise crack; or he is too good to make it himself, but was strictly a business decision. I not only have woodworking tools but metal working tools at my disposal so the reason I would not use them is this:

When you get into production saving $2 on each kit is the cost you are most interested in. The fixed cost of the winder seems small when you have to average it out over thousands of sets of pickups.

So assume if I paid more for each pickup $2 certainly seems cheaper than saving $300 on the winder but its not.

I own one of those Schatten winders... the older one with the metal case. It's not a bad winder, but it's over priced. It's not worth $350. $200 maybe. It's a bit crudely made... I had to square up the wire guide to the "tower". The motor is a bit underpowered, and while it works fine on 42 gauge and higher, it will barely work on something like 36 AWG. I tried it. It could not wind a usable coil.

(BTW, some "Charlie Christian" pickups used 36 AWG. Les Paul Recording pickups were even heavier gauge... I think 24)

If you are looking for an out of box experience, the Schatten winder will do it. I bought it for precisely that reason... I didn't have my workshop set up at the time, and didn't have room to build my own winder, or a place to keep it.

The Schatten has been working well for me, but as I step up production on pickups, I will be outgrowing it.

My next step is to build a CNC controlled winder.

Hey.

I want to put LEDs on one of my guitars i'm building, and I want to know is how you put them and if the Truss Rod can brake them.

Considering that the truss rod can break them when it administer some pressure.

Frank.

If the LEDs are going into the fingerboard face (i.e. where the position dots are) most of the LED will be buried in the fingerboard. You need to use low profile LED's. The wires will be in a shallow channel on the underside of the board.

If you are using a truss rod that installs flush with the top of the neck blank, I'd put a hard veneer between the neck black and fingerboard (such as maple or purpleheart, etc.). I do this on all my necks anyway. You can glue that veneer to the bottom of the fingerboard after your LEDs are in and tested.

newbyish question here.

i just got a 60's dearmond soundhole pickup that i want to use on my acoustic but there is no way i am drilling a hole in my martin....so i wanted to switch the existing input jack to a chord with a 1/4 plug. this is a simple change right? any suggestions/ tips?

Where is the 1/4" jack? On a cable from the pickup? Why not used an enclosed jack and plug a path cord into that. That's neater than either splicing a longer cable onto the wire from the pickup, and you don't have all that cable hanging out.

The professional way to do it is add and endpin jack to the guitar. That want detract from the value of the martin.

Those old DeArmonds can be valuable pickups, I wouldn't alter it any more than you have to.

David, I agree that the Bartolini design has a very small variataion of the magnetic field intensity in the horizontal direction. But this solves a non-existent problem. The field from a pickup changes quickly in the vertical direction. You know this because the output gets weaker as you increase the height of the string. If the field of a round pole pickup changed as quickly in the horizontal direction, string alignment over the pole piece would be critical, and even very small bends would cause a big loss in signal. Neither happens with the standard round pole pickups.

I don't think he was trying to solve a problem. If any it was cross talk between strings. Mainly he was as stated in patent 3983778, is making a design that "provides a highly asymmetrical magnetic field for preferentially sensing and generating electrical signals responsive to string vibrations perpendicular to the string plane." He explains in both patents that acoustic instruments reproduce the sound of the vibrations perpendicular to the string plane, as that's the direction the sound board moves. The parallel segment of the vibration doesn't produce movement in the sound board.

In 3983778 he states: "the rate of change of magnetic flux in the horizontal direction is much less than the rate of change in the vertical direction. The rate of magnetic flux in the horizontal direction approaches zero."

Other parts of both patents deal with "bending". Actually small round pole pieces do indeed cause signal loss when you bend. This is why Fender used two poles per string on bass pickups. The poles are much closer together on guitar pickups, but you can hear it as compared to a blade pole piece.

You did say: "Horizontal motion has not been considered in the work above because an examination of the fields produced by FEMM indicated that vertical motion is the dominant effect for the circular pole pieces assumed."

See, but what if you are not using circular pole pieces? The whole design behind the Barts, and some other pickups, is in not using circular pole pieces;

"The pole pieces have a rectangular cross section. The system further includes planar poletip faces having a planar configuration of an isosceles trapezoid. Sensing coils are disposed around each of the pole pieces. Again, the combination of the rectangular pole pieces and the trapezoidal planar poletip faces provide an asymmetrical magnetic field region surrounding each string of the instrument which preferentially senses and generates electrical signals responsive to string vibrations perpendicular to the plane of the poletip face."

If you've even used Bartolini pickups, especially the early Hi-A versions, you can see that he succeeded in getting a very clear almost acoustic like tone from the instrument. That's not to say everyone wants that tone, but I'm posting this info as an example of the way pickup designers manipulate the magnetic field shape to get different tones.

I do not know why individual coils give a clearer sound. I have made such pickups, but not noticed the effect.

Bartolini states:

"Above the resonant frequency, the impedance is by the capacitive effects between turns of the coil and between layers in the coil winding. Specifically, the changing current in one turn of the coil influences the current in the neighboring turns of the coil. This effect becomes larger with increasing frequency that the coil behaves as a capacitive reactance with turn-to-turn capacitive leakage to ground. Accordingly, the output signal from the sensing coils falls off rapidly above the self-resonant frequency. Since both the inductance and capacitance of a sensing coil vary linearly with its mean radius, replacing one coil by multiple small coils can reduce the impedance the pickup system by a factor equal to the number of coils and raise the self-resonant frequency by a factor to the square root of the number of coils."

You said "Also, the circuit discussion in the last paragraph cannot be applied generally. For example, in a passive system, it is the cable capacitance that dominates (with the volume up), not the inter-winding capacitance."

But this isn't true. Ask any pickup maker that pots their pickups in wax and they will tell you it reduces the high end of the pickup. This made no sense to me until it was pointed out the dielectric constant of beeswax is 2.7 - 3.0, and paraffin wax is 2.1-2.5.

You would think it doesn't matter with insulated magnet wire, but this isn't the case. Even the insulation type and thickness effects the tone.

And we all know that "scatter" winding makes a brighter sounding pickup, and it's assumed this is because the turn-to-turn capacitance is lower.

There are many patents dealing with this very thing. In the 1973 patent #3715446, Kozinsky states:

"Because of the large coil structure surrounding the six pole pieces, the capacitance of the winding is very high. For example if the six pole pieces are spaced over a two and a half inch, distance , then the coil wound around the six pole pieces would be approximately five inches long. Since capacitance increases directly with the length of the winding and since there are several thousand of such windings for each coil structure, the capacitance becomes very high and causes a serious reduction in its capability of reproducing all of the higher order harmonics and thereby reduces the quality of the sound reproduced by the instrument. Second, because one coil structure is wound around a plurality of pole pieces, rather than around each individual pole piece, the magnetic lines of force produced by the pole, pieces will only cut two sides of the coil structure rather results m low attenuation of all high order frequencies than all four sides. This results in a decreased induced current and therefor adversely affects the sound reproduced by the instrument. This loss is compounded by the fact that the magnetic field is reduced by the square of the distance, between a pole piece and the coil structure."

I actually sent them an email to ask them what the effect on the tone would be, since all they said was that it would "act like a switch", but I got no reply from them. It's been... 4 days since I sent the email?

I asked them a similar question once and got the "acts like a switch" response. It doesn't make sense to me. A pot is just a voltage divider, and it should work as intended as long as it's impedance is large compared to the source impedance. I have an EMG equipped guitar (with 25k pots). I thought about trying some 500k pots to see if the "acts like a switch" statement is true, but I've never actually gotten around to it. I'm not saying it's not true, but I can't seem to figure out why it might be.

With audio taper pots, the volume comes up real quick when you use 500K pots with EMG's. It's not the end of the world though. As I said I have a frankenstein guitar that I slapped together real quick, and I used the 500K pots they were on the pickguard. I wanted to try out an old Overlend EMG mini humbucker I picked up. I stuck that and an SA at the neck. I haven't felt the need to change the pots, even though I have a whole box of 25K EMG pots.

So I would use the ones they supply, but they will work just fine with higher values.

You can put them anywhere on the instrument you like. Talk about putting them on harmonic nodes is nonsense, because as soon as you fret a note, the harmonics move.

Put them where they aren't in the way, and so they look good with the design, and not too close to each other, or too close to the bridge.

Why do you need that particular rod? It's just like the ones from Stew-mac and LMII, and they tell you the dimensions!

Their rod isn't any smaller than the standard rods from LMII.

is there a cheaper way then buying the stew mac bit? i messed up my buddys silvertones pickguard and you cant buy them so i have to make one. What do you guys think?

Don't buy your bits from Stew-Mac. Get a pattern bit from a woodworking catalog.

You first need to make a pattern. Get some 1/2" plywood and shape that exactly as you want the finished part. Then double stick tape the plastic to the pattern and use the router.

I use the router upside down in a router table, or with a real wide base upside down, clamped in a vice.

Watch your fingers!

Wife's Rickenbacker bass seems to have an ash neck (through body). I assume it's the heavy ash, not the swamp stuff. Quite different. Maybe they should have completely different names, because we are all too dumb for two different things having the same name.

Ricks are maple, not ash.

An ash neck should be fine. MTD (Tobias) makes a bass with an ash neck.

Swamp ash can be any spices of ash, but it's graded by weight. "Real" swap ash was submerged under water. For a neck I'd use hard ash.

Do yourself a favor and laminate some carbon/graphite in the neck. We make necks from stuff like poplar and limba, and they work fine. You really don't need a hard wood for a neck, but you want the neck to be rigid.

I just bit the bullet and got the StewMac one (and i'm not one for spending money on StewMac stuff) but I built three winders and I wasn't happy with any of them. The one StewMac sells is made by www.schattendesign.com and is truely am amazing piece of work and is well worth the money they ask for it.

The counter is optical which means it won't mess up like a standard click counter will.

I burnt my click counter up on my 3rd design becuase the "hand drill" I was using spun too fast for it.

This design looks good and I know a ton of people have made thier own but Schatten's tool was just to easy to sink the cash into and it really works.

I have one. I think it's over priced, but you are paying for the hand work that went into making it.

On the plus side it works perfectly, and I can store it back in the box when I'm done, which is good, since I wind on the kitchen table! There's no room at the work shop for the winder at the moment.

I plan on making an automated winder soon...

But outside of that, my primary thought is that the Peavey amp has more to do with the sound on those video clips than the pickups.

There you go. Listening to a high gain amp with distortion is only showing how well the pickups work with that amp and that tone.

Consider the rather low output pickups Hendrix used, plus he kept them pretty far away from the strings.

_{( that was my opinion & believe the video shows how it nails the Black dog tone)}

And IMHO that sound is far away from the Black Dog sound. Compare the “black dog” sound of the WB pup with the live clip of Black dog. Not even close. Overtones mid, higs, lows, everything differs. And to my knowledge the pickup was supposed to deliver the Peter Green sound, remember…

I didn't bother to watch the videos... But I bet you are right! I had to reply to this post because the original was edited...

Why does everyone think that Page only played a Les Paul? He played a Paul live, but in the studio he used a brown Tele, a strat, a LP, and who knows what else. The Tele became his main guitar later on and had a Parson's White string bender. The electric parts, including the solo on Stairway to Heaven is the Tele. Hear that tone? That's Page's tone. Listen to The Ocean? Dancing Days? Achilles Last Stand? Nobody's Fault? You gonna tell me that's a Les Paul? Some might be, but some are definitely not.

Plus if that even is a Les Paul on Black Dog, it wouldn't be the neck pickup!

That was why I commented on this originally. Page's tone? Which one?

And why's everyone so damned interested in copping someone else's tone so bad? It's not that hard to come up with a good tone.

I'd have between 27-30k in output, blowing away an X2N or Dimebucker.

Well DC resistance doesn't equal output, and unless you had them both in series, the output DC resistance would be halved.

2 X 15K = 7.5K in parallel.

In series you would have a pretty muddy tone.

The work presented here is pretty much in conflict with what Bartolini says. Consider this part of the patent write-up you quoted:

"For example, pickup systems with circular pole pieces provide a magnetic field having the form of a symmetrical sinusoidal shell and a string vibrating within such a magnetic field will generate approximately equal magnitude electrical signals for string vibrations both parallel and perpendicular to the string plane."

Horizontal motion has not been considered in the work above because an examination of the fields produced by FEMM indicated that vertical motion is the dominant effect for the circular pole pieces assumed. I cannot put a numerical value on the v/h ratio; that would require more work, but it certainly appears that the horizontal is significantly smaller than the vertical. It looks like what Bartolini is saying is incorrect.

If you look at the diagrams on the patent, and also patents by Attila Zoller (3588311), you will see that what they are doing is arranging the lines of flux is such a why as that the string cuts through them on the vertical portion of it's motion. Bartolini does this by having a flat topped square pole piece which produces a low wide field over the pickup, instead of the high vertical field as you find on round poles. So think of the lines of flux in a high narrow field... they are mostly vertical, while a low flat field they are mostly horizontal.

Also, the circuit discussion in the last paragraph cannot be applied generally. For example, in a passive system, it is the cable capacitance that dominates (with the volume up), not the inter-winding capacitance.

His point was that by uses multiple smaller coils, instead of one large coil, you get a clearer tone. This has been used to good advantage by other builders too, such as on WAL basses. It does work, so there must be something to it.

So the question is this: if a string moves in a sinusoidal way, how non-sinusoidal is the response of the pickup. (We know the string motion is not a simple sinusoid, having various harmonics, but let's start simple.) To answer this question, we think of the string moving such that the time history of the distance from the pole piece traces out a sine wave. This corresponds to "motion" along the green line; we pick out the point we need at each time. Since we have the function at certain evenly spaced points only, we use a spline interpolation routine to generate the time sequence that we want.

A lot depends on the shape of the flux field over the pickup. An interesting thing is the movement of the string perpendicular to the top produces a different tone from the parallel movement. You can hear this on an unplugged solid body by plucking the string Bill Bartolini and a few others shaped their flux field over the pickup to not pickup both movements. Bartolini was interested in the movement perpendicular to the top, as that sounds more like an acoustic instrument, since that's the direction the sound board moves the most.

So... if Femm models magnetic fields, we also have things like the geometry of the coil to account for (plus the aspects of the coil itself.. wire gauge, number of turns, etc.)

The two Bartolini patents; 3983777, and 3983778 are very interesting reading.

Here's some good stuff...

The described pickup provides a magnetic field in the string plane having a large flux gradient perpendicular the string plane and a minimum flux gradient parallel the string plane.

Basically, the tone of a plucked or a struck string instrument is judged by the richness and complexity of the acoustic output in the "attack" or beginning portion of a note. In acoustic string instruments, the bridge structure

constrains the motion of the soundboard such that those components of string motion which are perpendicular to the, plane of the soundboard are well amplified, while those components ofthe string motion are parallel to the plane of thesoundboard are not. The path described by any arbitrarily small segment of a smoothly released, plucked string is a precessing elliptical orbit of decreasing radius which rotates about the quiescent position of the string. Accordingly, the asymmetrical amplification of string motion provided by the bridge of an acoustic instrument yields a rich, full and complex tone of continuously varying, harmonic content. The richness and complexity of tones produced by acoustic string instruments are the primary criterion of judging the quality of such instruments.

The prior art variable reluctance pickup systems are characterized by separate pole tip and/or pole pieces for each string. Each pole tip and/or pole piece provides a distinct magnetic field region around the quiescent position of each string. The distinct magnetic field regions of prior pickup systems render them relatively insensitive to the plane of vibration of the particular string.

For example, pickup systems with circular pole pieces provide a magnetic field having the form of a symmetrical sinusoidal shell and a string vibrating within such a magnetic field will generate approximately equal magnitude electrical signals for string vibrations both parallel and perpendicular to the string plane.

Prior art variable reluctance pickup systems having a single coil for sensing variations of the magnetic circuits have very poor high-frequency responses. Specifically, the impedance of a sensing coil in a magnetic circuit increases with increasing frequency up to a maximum at a resonant frequency whereupon the impedance of the coil decreases. Below the resonant frequency, the impedance of the coil is dominated by inductive effects. In explanation, the resulting variations in magnetic flux due to string vibrations induce an electrical signal in the coil which, in turn, creates another magnetic field which "bucks" or opposes the variations in flux induced by the string (Lenz' Law). This effect "impedes" the signal and increases with increasing frequency. Above the resonant frequency, the impedance is influenced by the capacitive effects between turns of the coil and between layers in the coil winding, i.e., the changing current in one turn of the coil influences current in rieighboring turns of the coil. This effect becomes larger with increasing frequencies such that the coil behaves as a capacitive reactance with turn-to-turn capacitive leakage to ground. Accordingly, the output signal from the sensing coil falls off rapidly above the self-resonant frequency. Both the inductances and the cpacitance of a sensing coil vary linearly with the mean radius of the coil. The mean radii in single-coil embodiments of prior art variable reluctance pickups are large. Hence, the "attack" portion of a note is not reproduced accurately.

Now what the heck has happened to the resent Peter Green craze? I haven’t heard his name mentioned in like 20 years, and suddenly everybody should do that silly “Peter Green” mod.

It's called "marketing". This same person has been hawking these videos over at the MLP forum.

Everyone got cool tones back then... look at Mic Ronson. Gear has changed, and so have playing styles. Everyone uses a lot of gain now, and you loose those old tones.

Peter Green was a fine player, but I'd rather listen to Gary Green!

David, you raised a good point with the usage of some CA glue. I'm think it's pretty wise to use some glue if I'm going to be beveling the edges of the fret slots. Just for added security. Any thoughts, anyone?

You know, sometimes I bevel the edges, sometimes I don't. I just forget to do it! I generally hammer my frets in when I'm working at home, and I have an arbor press with the Stew-Mac cauls at the workshop, but I haven't used that in a while.

I've hammed more frets in than pressed over the years. But now I always use CA. I apply a little to the slot, seat the fret on it, and hammer across the width. If an end doesn't want to stay in, I hold it down with the hammer while the glue sets.

I'm planning on pressing them in as standard on the next bass I'm making. I've tried different techniques over the years. On one bass I used a Dremel to widen all the slots and pressed the frets in with epoxy. It turned out great, but it was a lot of extra work.

I use the glue as both a lubricant, and as added security. It also seems to help from having loose frets. That's not a problem unless you are doing a refret... sometimes the slots are worn a bit, and you end up with a loose buzzy fret.

I also always have to do some leveling. I hear builder claim they just press them in and they are all level, but my experience is they rarely seat perfectly level, and there are always some variations in the fingerboard that seem to develop as you are fretting.

But in the end I achieve a nice low action.

Ok Im willing to reopen this build, I still hate the color and looks of the wood but the design is still strong in my mind.

I have to wonder why you would use putpleheart... it's a very hard heavy wood... and purple. I'd never use it for a body.

You do realize it will darken up as it oxidizes? Also it will be much darker with a finish on it. I use purpleheard for body and neck laminates all the time. Also if you put some danish oil on the wood before you finish it it will make the purpleheart much darker.

You can see the purpleheart lamination is much darker here. This bass was made in '94.