Category Archives: Construction

Dead Bug! Prototyping SMDs

      Construction, Electronics, Hardware, How To, Infinity, Prototype

Gone are the days of DIP (Dual in-line) ICs. Most modern ICs are no longer offered in easy to use 2.54 mm (0.1 inch) pitch packages. The descendants of DIPs, the SOIC (Small Outline IC) and its friends (e.g. the TSOP (Thin Small Outline Package)) are shrunk down to 1.27 mm (0.05″) and even as low as 0.5mm (0.019″).

So how do we prototype using such tiny critters? We do it using the Dead Bug approach: A free-form construction, point-to-point soldering, often with the ICs flipped upside-down with their pins sticking up into the air like dead insects. The components are constructed, ad-hoc, using a bare copper-clad board serving as common ground. This construction technique drastically reduces electrostatic noise compared to other prototyping techniques using perf-boards or bread-boards.

Soldering a tiny TDFN-14 0.5mm package!

Dead-bug constructions are typically ugly beasts! We use a variation of the technique called the Manhattan Dead-bug Style, using small pads punched out of copper-clad board and glued into the main copper base. The pads serve as islands for soldering circuit nodes.

High efficiency Class-D amplifier

I like modular, reusable building blocks. And so we build small modules and connect them together, all on top of another bigger copper clad board. This construction is very favorable to noise sensitive electronics. The module you see here is a high efficiency Class-D amplifier.

 

 

Alpha Revisited 2017

      Alpha, Construction, Evolution

Time to revisit the Alpha and replace Alpha’s pickups with what else but Nus and XRs! Dimarzios out, Nu and XRs in… Ehmm, OK I suppose I’d refret the guitar as well.

In case you have no idea what Alpha is, check out this link. Alpha is a thru-Neck Carbon Fiber over Bamboo with a Carbon Fiber Body I designed and built a few years ago. I’ll have more of Alpha in the coming days. Stay tuned. I am highly considering building a few of these sexy Carbon Fiber guitars with even crazier ideas brewing in my mind over the years, perhaps in collaboration with a fine luthier in the U.S. or in Europe (To my luthier friends: send me an email if you are interested and let us talk). You want the bleeding edge, this is it! It will be a complete multichannel system with the Nu, Nexus and Infinity all standard features, just as I envisioned it when this all started a few years ago. Yes, Infinity! My holy grail is now within reach with recent breakthroughs!

Watch out!

Nu Update: Meet The Nexus

      Electronics, Manufacturing, Nexus, Nu Series, Prototype

Meet The Nexus. This small, hacker friendly breakout box connects your multichannel guitar to the outside world using a specialized (LEMO compatible) multi-pin connector for up to 12 channels of audio and 7 channels of analog control voltages for by-wire control of volume, tone, patch or effects. Audio may come from standard mono-pickups or from the Nu multichannel pickup. Analog control voltages are converted to MIDI control messages.nexus

Continue reading

“Sustain” Myth and Science

      Alpha, Construction, Infinity, Myths, Sustain

Question: Which solid body guitar has better sustain, the Fender Stratocaster or the Gibson Les Paul? If you were like me, you’d probably pick the Les Paul. I’ve taken it as plain truth that there’s no competition: Gibson Les Paul = incredible sustain. Boy, was I so wrong!

Nigel’s Guitar Room

Nigel’s Guitar Room

An article by Mottola, R.M. “Sustain and Electric Guitar Neck Joint Type”, piqued my interest. Mottola, in his experiments performed power analysis, spectral analysis, and listening evaluation on three types of solid body electric guitars with 1) Bolt-on neck construction 2) Neck-thru construction and 3) Set-neck (glued-in) construction.

Continue reading

Pre-Production Prototype

      Electronics, Nu Series, Pickups, Prototype, Six-pack

Onward

Hello! We’ve been busy. It’s been a while, but we are inching slowly, but surely, towards production. Let me present the Six Pack production prototype (v1.4). If you have been following this project, you will notice that this is very similar to the Six Pack version 1.1 prototype apart from a few design changes.

Six Pack 1.4

Six Pack 1.4

Features:

  1. Six low impedance coils (1300 turns, 350Ω D.C. Impedance, flat frequency response, 20Hz-20kHz).
  2. Modern, Low power, Low noise OPA2314 differential Op Amps.
  3. Single supply (1.8 V to 5.5 V).
  4. Stainless steel height adjustment screws and springs.
  5. Premium gold-plated, 2 mm pitch header connector.
  6. Precision 1% thin-film, low TCR, low noise, Yageo and Vishay resistors.
  7. Panasonic low noise film capacitors.
  8. Fender Stratocaster Profile (14 mm total height excluding connector).
  9. EMG style pickup enclosure.

Continue reading

Finally

      Alpha, Prototype

From concept to reality…

Presenting the Carbon Fiber-Bamboo Guitar prototype.

I still have to write more documentation. I am terribly lagging behind. Anyway, for now, here are some high resolution pictures. You should compare these against the original 3D images. I am immensely having fun playing the final prototype. Now I am focusing on production.

If you got here from nowhere, you’ll be missing out if you don’t check out the project in full. Nevertheless, pretty images are always nice to see.

(Click images to zoom)

Pearl Inlays

      Alpha, Construction, Mother of Pearl

I find the iridescence of Mother of Pearl simply irresistible. The original design as seen in the 3D CAD model had a stainless-steel Cycfi logo. Well, chrome and stainless steel is classy, no doubt about that. The 3D rendering is indeed gorgeous. Nevertheless, it can’t compare to Mother of Pearl. So now, I am starting to deviate from the original plan. The logo will be inlaid Mother of Pearl. The original design also had simple triangular LED fret markers. For the final prototype, the markers are inlaid Mother of Pearl with a motif reminiscent of reversed white-on-black pipe organ keys with small white LED dots in the middle. The truss-rod cover will also be Mother of Pearl.

Here are a couple of snapshots:

The Fret Markers. The motif is the reverse (white on black) pipe-organ keyboard.

Next: Pearl Inlays next

Zooming in a bit on the fret markers. Mother of Pearl is just so elegant!

Testing the LED lights. Small white LEDs are inlaid in the middle of each fret marker.

The logo. The real thing looks even better than the original 3D rendering.

Zooming in on the logo. The logo is hand crafted. For production, it might be better to have it cut using laser or water-jet.

One more snapshot. The gloss is just to protect the inlay. We haven't even buffed yet. The final result will have a mirror finish!

The Craft

Mother of Pearl Blanks

Shell inlays (not the cheap plastic substitutes) add value to an instrument. You can find real shell inlays only on priced high-end or custom-made instruments. Guitars endowed with shell inlays, from the simplest to the most elaborate, are works of art akin to fine jewelry.

Inlaying decorative shells such as Mother of Pearl (MOP) and Abalone takes time, patience and perseverance to master. The craft involve:

  1. Cutting suitable shells into blanks
  2. Grinding the shell blanks down to a flat surface
  3. Cutting the blanks into the desired shape
  4. Routing the cavity from the wood
  5. Inlaying the shell into the routed-out cavity

I’m not about to delve into the fine details of the craft but I’ll provide various links below that you can find useful if you want to get serious about this craft. You can also buy books on the subject. My favorite is the definitive bible of pearl work: Pearl Inlay” book by James E. Patterson.

Jeweler's Saw

While the art of inlaying has changed little over the centuries (the craft began in East Asia during the Tang dynasty), it is a lot easier now than it was before. Modern tools certainly made inlaying easier. The versatile Dremel rotary tool is an indispensable tool for routing inlay cavities as well as for cutting, sanding, trimming and deburring shell pieces. You can buy precision jeweler tools that are well suited for fine shell work such as the Jeweler’s Saw with fine blades from 35 teeth per inch (size 5) to 84 teeth per inch (size 8/0). If you do not want to go through the messy trouble of cutting and grinding the raw shells, you can also buy rough-cut shell blanks ready for cutting your design (that’s what I do) or even pre-cut shells for typical designs such as Les Paul square or trapezoid fret markers, dots, diamonds, etc. Finally, if you have access to laser or water jet cutting services, you can get extremely accurate results with minimum effort —simply draw the design using a vector drawing software such as Inkscape, Corel Draw or Adobe Illustrator.

Cutting the Blanks

Skipping the laborious first step (preparing the blanks from raw shell), I start out with some nice Mother of Pearl blanks. You can buy either plain or figured blanks. There are various grades. Exhibition Grade is the most expensive. It is flawless in every respect with no discoloration, no wormholes, no growth fractures and no undesirable flaws. AAA Fancy Grade is like exhibition grade but with only one flawless side. A Grade is almost like AAA with one flawless side but with potentially small flaws that can easily be avoided. Standard Grade is the cheapest entry-level grade. I buy from an MOP supplier in ungraded bulk. I grade the blanks myself and choose only the highest grade. Some blanks may have rather nice features except for one or two flaws that can be avoided.

For the prototype, I manually cut the logo using a Jeweler’s saw. For production, it might be better to have the shapes cut using laser or water-jet. For most of the work, a medium size blade will suffice. For more intricate curves, I use a finer blade, but I never had the need for sizes finer than 1/0. It takes time to master the use of the saw and it is perfectly normal to break a few blades before becoming proficient.

Rule 1: be patient.

Rule 2: be patient.

Rule 3: be patient!

Rule 4: see rule 1 to 3

Shell cutting sawboard

So you know I love jigs. For cutting the shapes, I devised two jigs. For the fret markers, I needed a jig that will give me accurate and repeatable round corners. I built a jig with a small adjustable swinging clamp (see image below). The jig is positioned adjacent to a table mounted Dremel with a small drum sander. The distance from the pivot to the edge of the drum sander will be the round corner’s radius.

The other jig is a standard sawboard for cutting the pearl blanks. You can easily construct this jig from plans provided in the links below, or the easy route: just buy one from StewMac. I built mine from plans I got from Pearl Inlay” book by James E. Patterson (see picture at right). It is very similar to the one from StewMac. I use a small aquarium air pump and hose for the dust blower —a must if you want accurate results.

Cutting the logo with a jeweler's saw and a pearl cutting sawboard

Patience! Tons of patience!

Smoothing with a needle file

Shaping the fret markers using a round corner shaping jig and the Dremel table-mounted.

Smoothing the truss rod cover after cutting

The truss-rod cover ready to be placed

Routing the Cavities

I use four routers: a 1500-Watt Makita 3600H for heavy routing, a 1200-Watt Ryobi ERT241200 plunge router for moderate routing, another 400-Watt Ryobi EVT400K trimmer router for light duty routing and trimming and finally, a Dremel rotary tool for precision routing. The Dremel is not just a router. It is such a versatile tool; indispensable for intricate work, including, but not limited to, routing. I love this tool!

The Dremel is the perfect tool for routing out the inlay cavities. I use a Dremel router base and various small end-mill bits. I’m quite disappointed with the plastic Dremel router base. While it gets the job done, I’m not quite happy with the fine adjustment. I’d probably get a StewMac Precision Router Base soon or build one myself.

To transfer the design to the material to be routed out, a thin layer of white water-based paint is first applied. A fine point inlay scribe traces the shapes’ contours while holding the inlay pieces down. Smaller, more intricate parts may be temporarily glued down using spray adhesive.

Tapered router bit

4-flute end mill

I start off with a 4-flute 3.18 mm (1/8″) solid carbide end-mill to cut larger chunks of material close to, but without touching the outline. I then finish with a fine solid carbide cutter tapered router bit. These bits taper from 0.48 mm (0.019″) to 0.8 mm (0.032″)) —perfect for fine inlay routing.

The headstock painted with white water based paint and scribed with the inlay pattern.

Routing the logo cavity. The small hose is connected to a small air pump to blow away dust.

Cavity fully routed out with the logo. The layer of paint easily wipes off with a damp cloth.

Gluing the inlay pieces with black epoxy. Making sure that excess glue is wiped off, the logo is now ready for leveling and sanding.

Rough routing with 3.18 mm end mill

Detail routing the fret markers using fine tapered router bit

Further Reading

  1. Pearl Inlay (book) by James E. Patterson
  2. Mother of Pearl
  3. The Inlay Pages
  4. Pearl Inlay by Sean J. Barry
  5. Mother-of-pearl
  6. Inlay (guitar)
Next: Neck Dressing next

Compound Radius Fretboard

      Alpha, Bamboo, Carbon Fiber, Construction

I am more of a melodic lead player and I play lead more than chords. I prefer slim necks with flatter and low action fretboards that do not “fret out” with aggressive string bending —yet one more reason why I am not fond of the ever so popular Stratocaster. I am really inclined to build my next guitar that’s built exclusively for lead guitar playing with a totally flat fretboard, like a classical guitar. But this one is destined to be more conservative and general purpose so I’ll keep the fretboard curvature.

The question is how much curvature? The modern Strat has an aggressive 241 mm (9.5″) radius while Gibsons have 254 mm to 304 mm (10″ to 12″) radius. Modern Jacksons, on the other hand, have what’s called “compound radius fretboards” which are really conical fingerboards which start out with a smaller radius at the nut and gradually get flatter (bigger radius) towards the other end. The Jackson is definitely one of my favorite axe in my arsenal. And, for this design, I will definitely have something based on the Jackson. The radii of the curvature starts at 304 mm (12″) and ends (at the 24th fret) at 456 mm (18″).

Compound radius cutting jig

For this to happen, we need, you guessed it: yet another router jig. The router rides on a platform that pivots on a stainless steel shaft which is oriented on an angle corresponding to the conical section with our desired start and end radii (304 mm and 456 mm). Swinging the mechanism back and forth will give you the correct radius at any given point in its entire length, thereby guiding the router over the block to be cut into a fretboard. This web article details this jig quite well: Compound Radius Routing Jig for Guitar Fretboards.

Now we sandwich the fretboard with 8 layers of carbon fiber laid up with laminating epoxy; 4 on top and another 4 at the bottom. The fretboard is vacuum bagged to remove excess resin and to ensure that there are no air pockets or bubbles that can ruin its sonic integrity.

Bamboo fretboard ready for layup

4 layers of carbon fiber

Bamboo fretboard sandwiched in between with another 4 layers on top

Vacuum bagged. Excess resin oozing out.

After 24 hours curing, it’s time to slot the frets. I love jigs. Jigs make tricky tasks easy to do accurately. Inspired by StewMac’s fret slotting miter box, I use another jig for cutting the fret slots. Finally, we trim the sides using a fretboard template with a pattern following router bit.

Released. Nice and smooth! Ready for trimming and slotting.

Slotted and trimmed

Further Reading

  1. Guitar Fretboard Radius
  2. Compound Radius: Explained
  3. Compound Radius Routing Jig for Guitar Fretboards
  4. Fingerboard
Next: Pearl Inlays next

Neck-Thru Construction (part 3)

      Alpha, Bamboo, Carbon Fiber, Construction

Wrapping the Neck-Thru

This installment concludes the Neck-thru construction series. As a final step, the neck is wrapped in 4 layers of carbon fiber to ensure maximum rigidity. We vacuum bag the whole thing to ensure that there are no air-pockets and bubbles and to make the carbon fiber layup hug the shape as tightly as possible while allowing the resin to cure.

Vacuum Bagging

Vacuum bagging is a method that uses atmospheric pressure to hold laminated components (laminating epoxy and carbon fiber) in place until the adhesive cures. Laminated components are sealed in an airtight bag. Atmospheric pressure exerts around 101 kPa (14.7 PSI) inside and outside the bag. A vacuum pump then evacuates air from the inside the bag reducing the pressure inside the bag. This negative pressure creates as much as 82 kPa (12 PSI) pressure differential that compacts the laminate resulting in excellent consolidation and interlaminar bonds. The vacuum also draws out trapped air (air-pockets and bubbles).

Vacuum bagging is a crucial step. I’ll provide some links below detailing the process.

Laying-up the first carbon fiber layer

Laminating epoxy applied in between layers

Yet more layers of carbon fiber

Vacuum bagging the whole thing

Excess resin being drawn out by negative pressure

The carbon-fiber wrap ends at the neck-body heel

Perfection! The Final Result

(Click to zoom)

Perfect!

Further Reading

  1. Basic Vacuum Bagging
  2. Vacuum Bagging: Basics
  3. Vacuum Bagging Techniques
  4. Vacuum Bagging Equipment and Techniques for Room-Temp Applications
Next: Compound Radius Fretboard next

Neck-Thru Construction (part 2)

      Alpha, Bamboo, Carbon Fiber, Construction

Installing the Truss-Rod

Now, we install our new Carbon-Glass Truss Rod. We begin by cutting the truss-rod slot using a router. At the headstock-end of the neck, an aluminum block is embedded for additional strength and rigidity. In all guitars, the weakest point is this area where the neck meets the headstock —a critical breaking point. In addition to improved rigidity and strength, any additional support here will enhance tone and sustain. The aluminum block also serves as a foundation that evenly distributes the load of the tensioned truss-rod over a wider surface area. This aluminum block is glued using high grade structural epoxy. The nut sits in direct contact above this block further enhancing sustain.

A cavity at the headstock behind the nut is provided with ample space for a hex key wrench to reach into the stainless steel Allen adjustment screw for tightening the truss-rod. Another cavity behind the aluminum block gives the truss-rod head (see Carbon-Glass Truss Rod) some freedom of movement.

With the cavity routed to specification, we begin installing the truss-rod. The stainless steel anchor at the body-end of the truss-rod is glued, again with high grade structural epoxy. Finally, to ensure against the possibility of the rod rattling, we add some silicone sealer into the channel. The sealer will dampen any unwanted vibrations that can spoil the sonic quality of the neck.

Routing the truss channel

Aluminum reinforcement block

Gluing the anchor using structural epoxy

Truss-rod installed!

Routing the Body

For the body part of the neck-thru section, we will route the pickup cavities, the bridge height adjustment screws, the string ferrules where the strings pass through the body and the tail block —a piece of aluminum at the bottom that terminates the strings and where the ball-ends are anchored with easy access at the back.

Body side view transparency

For this design, we will have 3 single coil (DiMarzio Area 69) pickups. The pickups are body mounted and can be installed from the back of the guitar (how many times have you ever wanted to change pickups without having to loosen or take off the strings?). For that reason, the pickup cavity goes through the entire neck-thru body but not through the entire body (see figure at the right).

The body top also has a mild curvature which we will shape using yet another jig. That’s what we will do first. The images below show the jig in action. The jig rides on two rails with the router mounted on an acrylic plastic base which is mounted on two wooden sides with the desired curvature. I use this type of jig anytime I need some curvature —works well all the time.

Curvature-shaping jig

Jig shaping the body top

You might be guessing that I use a variation of this jig to shape the fretboard as well, but no, I did not. This guitar design has a compound radius fretboard for which this type of jig is not suitable. More on that later.

Now let’s move on to routing the pickup cavities. It starts with proper preparation and layout. I have prepared beforehand acrylic plastic templates for single and double coil pickups for standard Strat and Les Paul style pickups. I cover the entire area with masking tape and draw the outlines first. It was tempting to use the Strat’s pickup positions which give it its distinctive sound, but 1. I use a slightly shorter 644mm scale (25.35″) and 2. I have 24 frets (the Strat has 21). 1 is not a problem —it can be scaled. The real deal breaker is 2. The Strat’s neck pickup sits at around the 24th fret position. Hence, for this design, I compensated a bit and came up with a hybrid Ibanez Jem (I am a proud owner of two of these lovely Jems) and Strat layout. I use the acrylic plastic template to guide the router using a pattern following bit. Before routing,I pre-drill the cavities using Forstner bits to minimize the router’s work.

Layout

Routing the pickup cavities

Finally, at least for the neck-thru body, we drill the top string ferrules, the bridge height adjustment holes and the aluminum tail block. The bridge height adjustment is also accessed from the bottom. There will be no unsightly screws at the body’s top.

Drilling the top string ferrules. I love laser guided drills!

The tail block at the bottom

Further Reading

  1. Neck Construction Tips and Techniques
  2. Truss Rod Installation
Next: Neck-Thru Construction (part 3) next