"CKWT switch" Works perfect but I'm humming

[dugg]

I just wired up a Tele/original design body that I made for an '88 Strat Plus neck my friend had in his parts drawer. The plan was to assemble it 'in the white' for a day to test the pickup positions, switching and ChrisK's 'woman tone switch', but it sounded so nice it stayed wired with masking tape holding down the switch plate for about a week while various guitarists gave it a whirl. This post is about the Woman Tone switch, but I'll give a little discription of the axe now and come back with pictures in a week or two when the finish is done. It has two GFS pickups, one fatbody tele (7k) and a 'boutique strat' (5.35k) coil. The tele coil is mounted close to the bridge, at about the distance of the G.E.Smith model, and the strat coil about a coils width from the other. A four position switch chooses single, series, parallel, other single. Also, a master tone (500k linear) and Volume (1M audio) and an on/off/on (spdt, sp3t?) mini toggle for the Woman Tone, which has an 0.047pf and a 0.022pf to choose one, the other or both.

First, the Woman Tone switch is bitchen! It works differently on different pickup selections, so some fiddling is required to adjust that 'WT notch' when you go from say, a single coil to the series selection. Turning the tone knob almost all the way down and 'flipping the switch aboot' (hell of a way for a yank like me to talk!) is a great way to hear the differences between the caps. With both pickups placed close to the bridge, and no neck pickup (not to mention the very light and stiff poplar body and high impedence pots) this axe is extremely bright to say the least. I've heard the word Twangy more times in the last week than....hmmm, well lets say I heard it a lot. But, you know, it's a lot easier to turn down whats there than turn up what ain't, and thats where the WT is a very cool thing on this particular axe. Thanks again guitar nuts and ChrisK!

Now, I actually do have a teensy problem. I meant to order two SCs that would be RWRP to each other, so that I'd have humbucking combinations, but I didn't specify that on my order and got two coils that don't cancel hum together. I like the sound of the GFS 'boutique alnico 5' and would consider plopping it in my Coyote Dancer Strat and just ordering another for this Tele-ish for my friend, but I'm curious about reversing polarity. Is this a ridiculous idea? I've looked at old posts here and other forums, but can't find anything more enlightening than the Stewmac info, which is not too thorough. I have some powerful (think they're rare earth) 1" magnets here, couldn't I just stick 'em in a vise and drag that pickup through? What you all think?

[cynical1]

If you reverse the magnet you'll have a reverse pole, but not a reverse wound.

Since you mentioned you already had a home for the pickup in question, and for the cost of a GFS pickup it might be wiser to buy a RWRP pickup for your guitar.

Happy Trails

Cynical One

[dugg]

Thanks CO, I figured that I'd simply reverse them wire thingies after doing the magnet trick But, you may be right in suggesting I save it for another project. I just thought I'd axe...er ask.

[ChrisK]

I have some powerful (think they're rare earth) 1" magnets here, couldn't I just stick 'em in a vise and drag that pickup through?

I'm not sure what "I have some powerful 1" magnets here" means. Are these in the pickup(s) or do you just happen to have some powerful mean magnets?

I'm not sure what "drag that pickup through" means either. Are you thinking of trying to remagnetize the pickup magnets?


Here's a thought; if a pickup has individual string magnets protruding thru the bottom as well as the top, just mount it upside down and reverse the wires. It will then sense RPRW.


I don't suggest moving the pole magnets in single coil pickups. The wires are "traditionally" wound directly over the magnets. If you move a magnet two things will happen; you will either be successful lucky, or you will have made a conversation piece.

[dugg]

ChrisK, I know about the windings on the polepieces and difficulty in physically reversing the magnets by pushing them out, and I also know that I could flip the pickup upside down to achieve RP. I was just wondering if anyone had tried repolarizing the existing alnico 5's with 2 much more powerful 1" rare earth magnets mounted in a vise, per the Stewmac method, as I mentioned in my first post. I suppose I could just order another pickup and use this one elsewhere, but I thought you guys might know something about other methods or consequences. No matter, thanks.

[ChrisK]

While I have seen and understand the StewMac method, I wonder how one accurately gauges the amount of magnetization effected on a given pole alone.

On a pickup with fixed pole pieces, balance could be an issue. I suppose that gap distance control could be used, but this is a non-linear function.

Duncan et. al. have a firm grip on this process, but it being a trade secret........


If one had ferrous cones that started at the diameter of the Guitar Repair Magnets (1") and tapered to a diameter roughly equal to that of a single pole magnet (1/4"), one could effect individual magnet balancing. One would still need to use plastic spacers to avoid touching the magnets with each other.

And, one still might need the magnetometer.
www.rbannis.com/files/magpricing.pdf

[dugg]

ChrisK, your cautionary tone almost inspired me to tackle the repolarization, but my friend who is getting the axe convinced me to just swap it with the (non RWRP) neck pup on my Coyote Dancer, which traded 1 hum cancelling SOoP for 2 hum cancelling positions in SC. Now, we're all happy, except no one dragged anything through the magnets...oh well. Only thing is, I have no way to choose the new GFS coil by itself. I'm building a new Coyote Dancer from scratch this time, maybe I'll use a four way for the 'slantbucker' this time for 17 combinations.

[dugg]

Ok, so her name is Joni Mitchell and she's very white and has big teeth and she's my puppy dog. So white in fact that my camera was quite bamboozled in the exposure department when I thought to put the guitar next to her. Joni loves to mug for the camera though, so I may try to redo the shot. Maybe with some dark glasses on? (on the dog Chris )


Here it is 'in the white' when it still had the GFS strat pickup which I later swapped for the neck coil in my Coyote Dancer strat. Tape on the control plate, pencil lines around the pickup cavities....



Backside 'in the white' Light not quite right to show 'invisible contouring'.


Front and back finished.

[cynical1]

She's a pretty one...and the guitar ain't bad, either...

Interesting design, and a nice job on the guitar. Feel free to fire up some sound samples so we can see what she sounds like. (...the guitar...not the dog...)

And sunglasses and a fedora would be suggested for the dog...my dogs love fedoras...

Happy Trails

Cynical One

[dugg]

Thanks Cynical One, I don't think I have a fedora around, but I'll start warming her up with a beret and keep a look out for one Have to wait on my friend for the sound samples because I handed the axe off to him already. Only four pickup positions this time, but the CKWT switch is pretty deep and requires some experimentation. One thing I noticed as a preliminary observation is, the sharp angle of the pickups makes each string's sound harmonically different from the others. Also, the distance between the coils seems to give a more open sound than a traditional HB, or two SC's side by side like my Coyote Dancer.

[cynical1]

A beret works too...after all , she is a girl...

I'd be interested to hear the CKWT samples. I've got it designed into all the projects I have in the works.

I also have two single coils slanted severely on project #2. The body originally had a 24 fret neck, and the neck I have is only 19 frets...so the humbucker is farther from the bridge then normal. This puts the single coils closer then normal. Not as close as yours, but close.

If nothing else it will sound unique. What more can you ask for in a custom guitar?

Happy Trails

Cynical One

[dugg]

"If nothing else it will sound unique. What more can you ask for in a custom guitar?" Truer words were seldom spoke, brother. That's the quote of the day. I'm often amazed when people go to all the trouble to build an axe that's either identical to some common off the shelf one, or with differences so minor there's nothing to be learned.

I'm interested in how your ears will hear the overstock slanted SC's on your #2, Cynical1. Do you have a post for that build that I missed? Pickup positioning has so much influence on the character of the finished guitar. I think people often give more credit to the pickup itself than it's position on the guitar.

I had breakfast with the owner of the 'Black Tele' this morning. I bought his old FordExploder from him, so we were talking mostly about cars, but he did mention that the new Tele was fearfully bright, even after 'getting used to it' for a few days. I wonder about a change of cap(s) or tone pot value? The two caps in the CKWT switch are .022 and .047 right now and the tone pot is a 500k. What you think about that Cynical1?

[cynical1]

Apr 7, 2009 14:47:34 GMT -5 dugg said:

I'm often amazed when people go to all the trouble to build an axe that's either identical to some common off the shelf one, or with differences so minor there's nothing to be learned.

I couldn't agree more. If you can't make it different, or improved, what's the point? It's akin to re-inventing the wheel...

I'm interested in how your ears will hear the overstock slanted SC's on your #2, Cynical1. Do you have a post for that build that I missed? Pickup positioning has so much influence on the character of the finished guitar. I think people often give more credit to the pickup itself than it's position on the guitar.

I'd like to hear it too... The projects are pretty much on hold until the employment situation improves. Unlike Congress, I can't just legislate more guitar building funds...

The only post I have is on the wiring for the guitar. I stole most of it from JohnH's design, and ChrisK set me straight on everything else. Nothing on the build yet. Lack of a digital camera doesn't help either...

I was thinking the same thing about pickup positioning. I'm not a fan of the bridge pickup by itself anyway, so on build #2 the bridge humbucker is 3" forward from bridge rollers to the center of the pickup. That should darken it up a tad.

I wonder about a change of cap(s) or tone pot value? The two caps in the CKWT switch are .022 and .047 right now and the tone pot is a 500k. What you think about that Cynical1?

You might want to drop the pot down to a 250K. I'd try and talk him into the CKWT mod. That way he has more flexibility on his guitar. I mean, you're already de-soldering and putting in new stuff anyway...what's one more hole? And the parts are dirt cheap for the benefits it offers.

Happy Trails

Cynical One

[ChrisK]

Well, ya know, a 500K audio taper pot used for a two-terminal tone control is down to 250K at aboot (Midwestern for about) "7" or "8" on a Strat knob. Also, these knobbular tone thingies are adjustable.

If that doesn't quite do it, one could apply the practice of Pickup Coil Response Tuning.

With the application of a simple low-valued cap and a series resistor (if needed), one can shift the resonant peak of a pickup lower in frequency. Now, one will have to spend perhaps a dollar at the grossly inflated prices for capacitors from guitar parts suppliers.

The best part is, one can experiment with this concept at the output jack by fabricating a cheap Radio Shack aluminum box with two 1/4" jacks, three banana jacks and a 250K pot. The jacks are wired straight thru, one cap terminal connects to the hot signal, one cap jack connects to the pot wiper, and the other (ground) terminal on the pot goes to signal ground.

The series cap and pot network works just like a tone control. One sets the pot to full off (zero Ohms). One plugs a cap into the two cap jacks and, if one kind of likes the sound with a particular cap, one adjusts the pot (increasing its resistance) to be sure as this will damp and broaden the effect.

Make sure that the guitar volume and tone pot(s) are set to "10" (full-on).

Measure the pot resistance at the ground banana jack and the jack at the node between the pot wiper and the cap.


I use a calibrated resistor that I have (actually a 0.1% resistance decade box just because I have it) and a variable three-section air cap for rapid testing. One can also get a 12 position one pole rotary switch and make a resistor/cap substitution box.



Once you find a combination for each pickup, solder said series network directly across the respective pickup's wires (or whence it's terminated).

[dugg]

This axe I'm talkin' abou...aboot, already has the two caps and switchy thing ala CKWT mod. If you look real close there in the pics you can see the little 3 position mini toggle down behind the tone control. Works a charm, that's what I started the post abou...aboot.

I was just musing about it's sound which is face melting bright. It's just a twang monster. It's not just in the pickups and their placement, you can hear the twang coming right off the body. Of course, the 1M volume pot keeps things bright. Guess I could try a smaller value dere eh?

I suggested that he twiddle the tone controls on the amp, which of course he had already tried. I think he just needs to grapple with the little monster a few more weeks. He's a good player, if there's something good about that axe he'll discover it. I'm inclined to think of it as an 'I.I.W.I.I.' (it is what it is) guitar. The original it was meant to replace was a single HB Tele, so this one is similar in it's lean and mean configuration.

I mean, with only four pickup positions, the wiring of this axe is hohum at best. Certainly nothing really worth mentioning on Guitarnutz, but with the unique combination and placement of pickups, and of course the CKWT switch to try and tame the whole operation, I figured some folks here might be interested.

ChrisK, your suggestion that I assign each pickup a dedicated cap and resistor might ultimately be what I'll do, but the existing 3 way switch with 2 caps and 500k tone knobby works pretty well. Like I said, IIWII. I'd rather change volume pot and 'speriment with other tone capacitor values first.

[newey]

Of course, the 1M volume pot keeps things bright.

Yep. You could use ChrisK's outboard test method to see how a 500k or a 250K would bring the brightness down a bit before committing to a change.

[ChrisK]

My point about pickup tuning is that an additional series resonant circuit can be added to each pickup if needed. This is usually a higher frequency filter than the high-cut tone control, and affects a different part of the frequency spectrum.

Even if the 0.015 uF value is chosen in the CKWT circuit, a 0.001 uF to 0.0047 uF cap with a chosen series damping resistor can help lower the frequency peak of a pickup independent of, and aside from, the normal tone control action

After all, a graphic equalizer doesn't modify just one frequency band!


This is not a tone control in the normal sense. It's independent pickup response tuning. A simple cap and resistor can tailor a glassy Strat pickup into a mid(ier) sounding slightly overwound sound.

An overwound pickup has more wire; this effects a slightly higher output voltage and more inductance which, in conjunction with the internal series distributed capacitance and external to the pickup cable and amp input capacitance ( ), effects a lower frequency response peak.

A standard wound pickup with additional external capacitance has the same frequency response as an overwound pickup.


Gee, hmmm, an extra 0.001 uF of capacitance. Just tell them to use a longer or crappier (more capacitance) guitar cable.

;D ;D


After all, the "sound of the '70s was defined by the 25 foot coiled cord!




And would you please stop that blasted humming............