Guitar Effect Test Box

I’m in various stages of completion for several guitar effects at the moment and I’ll certainly try to write a post for each of those in turn. However, I first figured I should post about my guitar effect PCB test box I put together. I by no means first came up with the idea. Paul of DIY Guitar Pedals in Australia is who I first saw use & recommend one. In searching around for further ideas, I came across some notes on DIY Stomp Boxes about adding the probe, which can be used in diagnosing PCBs that aren’t working.

A MXR MicroAmp circuit hooked up to the test box

As you can see, I went with a fairly large enclosure for this project. As it’s really just the off-board wiring standard to most any pedal project, with no circuit board, this is somewhat a waste of space. However, I wanted to leave a bit of space for potentially adding some more features at some point in the future1. This is a powder-coated, aluminum enclosure which is not at all necessary for this, as the wiring is outside so the metal box isn’t shielding anything. So the enclosure was a bit of a splurge. But as Mammoth currently sells these 1590BB enclosures powder coated for under $10, it’s not exactly a bank-buster. The entire test box is less than $25, and many of the parts I already had in my parts bin.

I cut up some cheap alligator clips I bought off of Amazon.com to use for the connectors. They have little covers over the clips, so they work quite well even when connecting into closely spaced wiring leads. I did knot these just inside the box to provide some strain relief (though it’s not as though this thing is getting roughed up much). I used a Mammoth Electronics bypass wiring board just to simplify things a bit. I tend to use a standard wiring colors for all my projects: red for 9v, black for ground, green for signal to board, and yellow for signal back from board.

The spacious guts of my test box

The one trick my box has is that I added a toggle switch to use a testing probe. This switch basically hi-jacks the signal return (yellow) and connects the probe (white) directly to the box output jack. So if signal isn’t coming back from the circuit, I can flip this switch and then use the probe (which is nothing more than a 1μf capacitor) to touch along the circuit to trace where the fault is. It’s very simple but incredibly helpful.

So to quote Paul of DY Guitar Effects, if you’re going to even build just more than a couple of guitar effects yourself, you’re going to want to build something like this. It’s so invaluable to be able to test your PCB as soon as you get the components installed but before you try to complete all the off board wiring & stuffing it into an enclosure. It’s also extremely fun to hook up to a breadboard and test that way!

A Bazz Fuzz breadboard circuit on the test box
My enclosure drill pattern
Wiring diagram for my test box


  1. For example, I also saw this post where someone has added in the ability to change the voltage and add a voltage sag (to simulate a dying battery), which is really cool. []

Tremolo Pedal Build

Christmas in 2018 was a lot of fun and my family got me a lot of wonderful things. Among them, my brother, Dave, got me a guitar pedal effects kit. This was a tremolo pedal, which is definitely something I wouldn’t have gotten myself. If you don’t know, a tremolo pedal modulates the amplitude of the signal. That is, it’s as if someone is turning the volume knob up and down regularly. This effect was built into many early electric guitar amplifiers. In the late 50’s an Australian electronics magazine had an article on a relatively simple circuit for this effect. That design has since been modified and incorporated into many popular guitar effects. The kit I got is by Arcadia Electronics and uses the EA Tremolo design.

This kit has all of the components, even jacks and switch, all directly soldered onto the printed circuit board (or PCB). This simplifies building and is, in fact, what most commercial pedals utilize to speed up fabrication (and even allow for automated component soldering). As such, it was a relatively straight-forward build process that probably took me under three hours total. And mind you, I am intentionally slow with this things because I want to really enjoy the process and also to prevent making any easy avoidable mistakes.

Populated PCB for the Acadia Tremolo pedal. You can see that I intentionally bent over a couple of the electrolytic capacitors to keep them well clear of the Depth control potentiometer.

The instructions with the Acadia kits are very sparse. They basically include of a printout of the PCB (which is very nicely screen printed and clearly marked, though) and a component list. That’s it, there’s no other instructions or build steps given. So, if this was a kit for a new builder, I’d suggest downloading the instructions for one of the other Tremolo pedals at Mammoth Electronics. They’re generally similar builds and provide some good information if you’re new to pedal building or electronics. The Acadia kit came with high quality components. I tested some of the resistors and they were closer to nominal values than the ones I purchase. The single diode in the kit had legs that really didn’t fit into the drilled through holes, but I just swapped it out for another 1N4001 in my parts bin. It’s not that the part was cheap; just that the pcb design as-drilled can’t accommodate this particular part. There’s probably several solutions to this, but this would be pretty frustrating for a first-time builder, I think. Otherwise, I really have no issues with this kit. It’s the first pedal build I’ve done that I didn’t have to troubleshoot at least one mistake!

I labeled the pedal once it was all closed up for testing. I’ll paint and decorate the case another day.

I got the hardware all soldered onto the board. I did add some electrical tape to the back of the pots as well as to the inside of the case back. This is probably not necessary, but I wanted to prevent any possibility of the pots or components grounding out.

The pedal sounds great. The volume boost on this was pretty surprising, in fact. Just dialing the Rate and Depth controls to zero makes this a pretty effective clean boost, even. The range of the tremolo is all the way from nothing to complete volume clipping. I recorded a fairly poor sample for this post, but the sound is really great in person.

Tremolo Pedal Demo

Repairing a Kid’s Bed

As part of my goals for 2019, I am going to try to write about some of my DIY and maker projects. So, here’s an unexpected one to start off the year…

The other evening, I heard a thud and an “uh-oh” from my 11yo daughter’s room. Turns out, when hopping on to the bed to read that night, the bed rail snapped. The bed rail was made from pressboard, veneered to look like the rest of the furniture (which I think is of slightly higher quality). Our daughter felt terrible about breaking the bed, but in reality it’s a wonder it lasted for the 7 years it did. An average size toddler could break this stuff, let alone an average size 11 yo girl. The pressboard had cracked in two pieces, right through one of the screw holes for holding the slats.

We considered purchasing a new IKEA bed or similar, but she said she really like this bed and would prefer if we could just fix it. Maybe that was partly her still feeling bad for having done it, despite my wife and I assuring her it wasn’t really her fault at all. The only downside to this was that I was going to have to purchase a full size sheet of plywood at the big box store to get the 6′-6″ rails out of them. I normally have the store cut the board along the short dimension, so that it’s less than 7′ long as to fit into my Honda Pilot. However, in hindsight, I should have had them then rip down some strips to make it easier to manage. A 6′-8″ by 4′ sheet of 3/4″ plywood is only slightly easier to manage by yourself than a full size sheet.

Old, pressboard rail (broken) and new, improved rails with hardware

I did get to try my hand at edge banding the plywood. Edge banding is a narrow, thin strip of veneer (almost exactly like the surfaces of hardwood plywood) that has a heat-activated glue on the backside. You simply iron-on this to the edge of your cut plywood.1 It’s actually a lot of nice furniture and cabinetry is made and it’s a pretty amazing transformation. Of course, it’s also how a lot of cheap furniture is made, too, but that’s often a plastic veneer rather than actual hardwood. I couldn’t find maple veneer at my big box store, so I took a trip to my local Woodcraft shop. There, I also got a self-centering drill bit. I’d always considered one of those to be for someone who makes a lot of furniture or cabinetry, but it’s worth it to buy some even for DIY’ers like me. It’s a huge timesaver for mounting hardware and really makes the process more accurate.

Using a self-centering bit made mounting the hardware a breeze

So, I ripped down the nearly full sheet of plywood on my little band saw. Again, I should have had the store cut this down, because it’s just not easy for one person to do this on even a high-end cabinetry saw, let alone a my small Ryobi2. It resulted in some not-so-straight cuts, but they were good enough for this as I wasn’t jointing anything. I straightened out some of the bend metal slat supports in my machine vice and then got all the screw holes drilled out.

I did a small test piece with the edge banding and tried using one of those spring loaded edge banding trimmers. The banding went on easy, but the trimmer was not so great. It ended up tearing the banding in a lot of places. I still tried using it one the first rail, which was a mistake. When trying to sand everything, the orbital sander grabbed one of those tears and ripped off a huge chunk of the banding. Fortunately, I was able to cut out that piece by re-heating the glue and Angela helped me put on a patch. It ended up looking just fine for our kid’s bed, but I learned my lesson. For the second rail, I simply flipped the piece over and cut along the edge with a box-cutter blade. I then lightly sanded over the corner with a sanding block.

I used a single (though pretty heavy) coat of wipe-on polyurethane for the finish. The final step was to stamp the work and then it was ready for assembly this afternoon. The final clip sliding in to place was so satisfying! The maple matches the furniture, but of course it will have to darken over time with exposure to light to fully match. But, I’m pleased with the final result and I’m confident this will last longer than the original.

Stamped and in place
Like new again!
  1. If you want to know more about edge banding, Bob of ILTMS made an excellent “Bits” video on the subject late last year. []
  2. It’s actually my older brother’s table saw. He just needed a place to keep it and I needed one to use, so that worked out for us. []

Learning to Weld

Something I had wanted to learn for many years is basic welding. I’m not planning on switching careers or anythingThough you can make an excellent living as a welder and I would encourage any young person interested to learn about that trade.; I just wanted to try it myself. As a structural engineer, I’ve spec’d countless welds on paper. I’ve only ever done very limited metal work (mostly just cutting, drilling, & bolting), and I wanted to get a feel for what it’s like to join metal with welds. I’ve learned from some of my engineering friends, as well as watching Grady at Practical Engineering, that I’m not alone in this interest.

But it’s not necessarily easy to find a teacher for a curious person rather as opposed to a student who is seeking a career. I don’t have a lot of friends that weld, either. But, maker spaces often have introductory courses. So, I found a great “Intro to Metals” course at Fort Houston here in Nashville.

For better or worse, I was the only person who signed up that Saturday, so I got a three hour, one-on-one course from Courtney Daily, who is a local artist who happens to work & teach at Fort Houston. I really recommend checking out Fort Houston for all sorts of classes. Courtney, especially is a great teacher (and, from what I saw of her work, a talented artist and damn fine welder).

Welder (noun): a person who fixes or makes shit you can’t 😋❤️🔥

A post shared by Courtney Daily (@courtdaily) on

Fort Houston Metal Shop

I first made a bunch of really ugly test welds to practice on some scrap. We also practiced cutting & drilling, which though not new to me was (is) still something I had a lot to learn about.

Ugly welds

My little beginner project was to make a frame. I made a rectangle out of 1″ angles. Since we had the extra time, I also got to spend some time grinding it down (which probably took longer than actually welding did, given my work). It ended up looking better than I would have expected for the my first project. I’ll probably find a way to mount some art in it (or maybe use it for a guitar pedal board, though it weighs a lot for that).

Ready to grind

Finished frame

Ground to the core

So, as I was finishing up grinding I made the comment that it looked shiny now, but it’d probably rust over by the next day. Courtney corrected me that the steel would stay fairly polished where I ground it for a long time. Well, it’s over three months later and it hasn’t rusted a bit.

  • Smart welder lady: 1
  • Know-it-all dude: 0

Reminds me I always need to listen & learn.

My First Stomp Box Project

For my birthday, I decided to work a completely new project: build a guitar effects pedal. I purchased the “Confidence Boost” project kit from BuildYourOwnClone.com (as in clones of popular guitar stomp boxes). It’s a great project for about $15 which comes with detailed instructions and makes a pretty decent little boost effect. The kit itself only comes with the printed circuit board, electronic components, and off-board wiring such as jacks and potentiometer.

PCB components and initial off-board wiring

I soldered up the components and off-board wiring and plugged-it up. And nothing. It didn’t make any sound! I posted a couple of photos to the discussion board and quickly got a response: the input jack was wired backward. In other words, the signal from my guitar was just going to ground and nothing was going on to the effect (or amp). I quickly re-worked the input jack and it worked. The tiny potentiometer (blue screw driver knob in the photo above) was a bit tough to use.

I decided it would be fun to go ahead and wire this up as an actual stomp box, so I ordered a few more components and an enclosure. I spent some time painting and finishing the enclosure. I just used a white pen to draw out the labeling, but it turned out just fine for this project. I read up on how to wire a footswitch for true bypass (when it’s off, it doesn’t affect the signal at all) and with an LED indicator light.

Enclosure design
Fully wired effect in the enclosure
Wired up and turned on

But of course, it only really matters how it sounds. I’m far from a capable guitar player and even worse when trying to film my playing, but here’s a small sample.