Don's first prototype
Reader: Don Baker
Hometown: Tulsa, Oklahoma
Guitars: First, Second, and Third Prototypes
This reader has two patents for his innovative pickup circuitry designs, which he’s implemented in two out of three of the prototypes he shares in this story.
I’m much less a guitarist or luthier than an engineer and inventor. I came up with a neat way to wire matched single-coil pickups into humbucking circuits (U.S. Patents 10,380,986 and 10,810,987). For two, three, four, and five pickups, you get one, six, 25, and 90 distinct humbucking circuits. For three pickups, you can get six more distinct circuits with hum. For humbucking (HB mode) you just add the outer line pickup(s) to the inner line on the 6-way switch label. Hum mode shorts out the inner line pickup.
The guitar industry has shown no interest, so I’m taking the long route, like Mr. Wally Byam, the founder of Airstream Inc. He started off selling plans to make his travel trailers. I planned on making a lot of mistakes, and used Photoshop to design a versatile plywood guitar body using a minimal amount of wood. It has a bolt-on neck (Saga Music Golden Gate S-94, with an unmodified headstock), a central spine below the pickups, two arcing ribs to enclose the electronics cavities, and laminate front and back covers. I make my own round guitar knobs, and do it all in my apartment and balcony (routers are very dusty). Anyone with a decent woodshop can make one.
A closeup of the switch and knob configuration on Don’s first prototype.
The first prototype, a white guitar, has three P-90s with N, S, and N poles up, bridge to neck, tone pots for each pickup, a 6-way switch with a 2-way mode switch (HB and Hum), a preamp to equalize the output amplitudes with switching, a volume pot, a moveable middle pickup, and a power LED which lights with the preamp when the guitar cable is plugged in. The second prototype, a black guitar, has three Allparts Vintage Chrome humbuckers, phase reversal switches on the neck and bridge tone pots, pickups moveable to any place between the neck and bridge, and over 20 distinct circuits.
“I’m writing a highly illustrated DIY journal on how it is made, including most of my mistakes.”
As I build the third prototype with three fixed-place Jazzmaster pickups (with the middle pickup poles inverted to S up) and Spanish cedar veneer front covers, I’m writing a highly illustrated DIY journal on how it is made, and including most of my mistakes. (I’m trying a lot of new things.) I’m up to about 24 chapters and a few hundred images. This time I’m thinking I’ll use just six humbucking circuits with a preamp. In exchange for buying the book, I intend to grant the right to make two patented/patent-pending guitars with non-amplified switching, and then sell the preamp separately.
Don’s second prototype.
It’s going slow. Since a drunk driver nailed me in 1985 when I was 39, I got old and only have a few productive hours a day. But every day, I do a little bit more.
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The Schaffer Replica® - BASS-X
After introducing the Schaffer Replica Storm low end legends like Rudy Sarzo, Billy Sheehan, and Pino Paladino discovered it to be equally amazing on bass. Based upon their input we made a few minor changes to this beloved circuit to make it more conducive to higher amplitude and lower frequencies. To our loyal bassists who have waited so patiently, we proudly introduce The Schaffer Replica - BASS-X.
Fender’s Greasebucket system is part of Cory Wong’s sonic strategy.
Tone pot with Fender Greasebucket tone system:
This 250k tone pot is a standard CTS pot with a 90/10 audio taper found in all U.S.-built Fender guitars. The Cory Wong guitar uses the Fender Greasebucket system, which is added to the pot as a ready-to-solder PCB. The Greasebucket PCB is also available individually from Fender (part #7713546000), though you can use conventional electronic parts for this.
Fender introduced this feature in 2005 on some of the Highway One models and some assorted Custom Shop Strats. The Greasebucket name (which is a registered Fender trademark, by the way) is my favorite of Fender’s marketing names, but don’t let it fool you: Your tone will get cleaner with this modification, not greasy and dirty.
According to Fender, the Greasebucket tone circuit reduces high frequencies without adding bass as the tone knob is turned down. Don’t let that description confuse you. A standard Strat tone control does not add any bass frequencies! As you already know, with a passive system you can’t add anything that isn’t already there. You can reshape the tone by deemphasizing certain frequencies and making others more prominent. Removing highs makes lows more apparent and vice versa. In addition, the use of inductors (which is how a passive pickup behaves in a guitar circuit) and capacitors can create resonant peaks and valleys (band-passes and notches), further coloring the overall tone.
Cory Wong bringing the funk onstage.
This type of band-pass filter only allows certain frequencies to pass through, while others are blocked. The standard tone circuit in a Strat is called a variable low-pass filter (or a treble-cut filter), which only allows the low frequencies to pass through while the high frequencies get sent to ground via the tone cap.
The Greasebucket’s band-pass filter is a combination of a high-pass and a low-pass filter. This is supposed to cut high frequencies without “adding” bass, which has mostly to do with the resistor in series with the pot. That resistor means the control will never get to zero. You can get a similar effect by simply not turning the Strat’s standard tone control all the way down. (The additional cap on the wiper of the Greasebucket circuit complicates things a bit, though; together with the pickups it forms an RLC circuit, but I really don’t want to get into that here.)
The standard Fender Greasebucket tone system is used in the Cory Wong Strat, which includes a 0.1 μF cap and a 0.022 uF cap, along with a 4.7k-ohm resistor in series. These are the values used on the PCB, and without the PCB it looks like the illustration at the top of this column.
Push-push tone pot with preset overwriting function:
The lower tone pot assigned to the bridge pickup is a 250k audio push-push pot with a DPDT switch. The switch is used to engage a preset sound by overwriting the 5-way pickup-selector switch, no matter what switching position it is in. The preset functionality has a very long tradition in the house of Fender, dating back to the early ’50s, when Leo Fender designed a preset bass sound on position 3 (where the typical neck position is on a modern guitar) of the Broadcaster (and later the Telecaster) circuit. Wong loves the middle-and-neck-in-parallel pickup combination, so that’s the preset sound his push-push tone pot is wired for.
The neck pickup has a dedicated tone control while the middle pickup doesn’t, which is also another interesting feature. This means that when you hit the push-push switch, you will engage the neck and middle pickup together in parallel, no matter what you have dialed in on the 5-way switch. Hit the push-push switch again, and the 5-way switch is back to its normal functionality. Instead of a push-push pot, you can naturally use a push-pull pot or a DPDT toggle switch in combination with a normal 250k audio pot.
Here we go for the wiring. For a much clearer visualization, I used the international symbol for ground wherever possible instead of drawing another black wire, because we already have a ton of crossing wires in this drawing. I also simplified the treble-bleed circuit to keep things clearer; you’ll find the architecture of it with the correct values in the previous column.
Cory Wong Strat wiring
Courtesy of singlecoil.com
Wow, this really is a personalized signature guitar down to the bone, and Wong used his opportunity to create a unique instrument. Often, signature instruments deliver custom colors or very small aesthetic or functional details, so the Cory Wong Stratocaster really stands out.
That’s it! In our next column, we will continue our Stratocaster journey in the 70th year of this guitar by having a look at the famous Rory Gallagher Stratocaster, so stay tuned!
Until then ... keep on modding!
Key Features of the ZOMA
● Intuitive Control Layout: Three large knobs give you full control over Reverb Level, Tremolo Rate,and Depth
● Easy Access to Alternate Controls: Adjust Reverb Decay, Reverb Tone, and Tremolo Volume withsimple alt-controls.
● Instant Effect Order Switching: Customize your signal path. Position tremolos after reverb for avintage, black-panel tone or place harmonic tremolo before reverb for a dirty, swampy sound.
● True Bypass or Buffered Trails: Choose the setting that best suits your rig.
Three Reverb and Tremolo Modes:
● SS – Spring Reverb & Sine Tremolo: Classic spring reverb paired with a sine wave tremolo for that timelessblack-panel amp tone.
● PH – Plate Reverb & Harmonic Tremolo: Smooth, bright plate reverb combined with swampy harmonictremolo.
● PV – Plate Reverb & Pitch Vibrato: Achieve a vocal-like vibrato with ethereal plate reverb.
Reverb: Sounds & Controls
● Spring Reverb: Authentic tube amp spring reverb that captures every detail of vintage sound.
● Plate Reverb: Bright and smooth, recreating the lush tones of vibrating metal plates.
● Reverb Decay: Adjust the decay time using the REVERB/ALT SWITCH while turning the Level knob.
● Reverb Tone: Modify the tone of your reverb using the REVERB/ALT SWITCH while turning the Rate knob.
Tremolo: Sounds & Controls
● Sine Wave/Volume Tremolo: Adjusts the volume of the signal up and down with smooth sine wavemodulation.
● Harmonic Tremolo: Replicates classic tube-amp harmonic tremolo, creating a phaser-like effect withphase-split filtering.
● Pitch Vibrato: Delivers pitch bending effects that let you control how far and how fast notes shift.
● Alt-Control Tremolo Boost Volume: Adjust the boost volume by holding the REVERB/ALT footswitch whileturning the Depth knob.
The ZOMA is built with artfully designed circuitry and housed in a proprietary angled aluminum enclosure, ensuring both simplicity and durability. Like all Keeley pedals, it’s proudly designed and manufactured in the USA.
ZOMA Stereo Reverb and Tremolo
The first sound effects built into amplifiers were tremolo and reverb. Keeley’s legendary reverbs are paired with their sultry, vocal-like tremolos to give you an unreal sonic experience.
Stevie Ray Vaughan was a force of nature. With his “Number One” Strat, he drove a veritable trove of amps—including vintage Fenders, a rotating Vibratone cab, and a Dumble—to create one of the most compelling tones of all, capable of buttery warmth, percussive pick articulation, and cathartic, screaming excess. As he drew upon an endless well of deeply informed blues guitar vocabulary, his creativity on the instrument seemingly knew no bounds.
Your 100 Guitarists hosts are too young to have experienced SRV live. We’ve spent decades with the records, live bootlegs, and videos, but we’ll never know quite how it felt to be in the room with SRV’s guitar sound. So, we’d like to spend some time imagining: How did it feel when it hit you? How did he command his band, Double Trouble? The audience?
SRV was mythical. His heavy-gauge strings tore up his fingers and made a generation of blues guitarists work a lot harder. And his wall of amps seems finely curated to push as much air in all directions as possible. How far did he take it? Was he fine-tuning his amps to extreme degrees? Or could he get his sound out of anything he plugged into?
