This is a basic element of many electronics projects: how to wire up an LED with a current limiting resistor. Most effects have a 5 mm LED and many wiring diagrams show a 4k7Ω resistor. There’s a fairly wide range of values you can use, depending on how bright you want the LED (and what the LED’s specs are). You can calculate out the exact value to use if you have the specs for an LED, but using a 4k7Ω works well enough for most situations.
What’s a bit less obvious is how to solder a resistor’s legs to an LED leg and the connecting wires. Here’s my method:
Using a pair of craft tweezers, I roll up the positive leg of the LED.
Then take the resistor leg and bend it through this loop, then twist it around once. This forms a chain-like connection.
Solder this connection and then trim the resistor leg back.
Curl up the outstanding leg of the resistor in a similar fashion.
Bend the tinned tip of your hookup wire at a 90° and hook around this loop to solder just like you would a jack connection.
Curl up the negative leg and solder a 90° bend from another hookup wire to this end.
Apply heat-shrink tubing over both connections. I picked up using the barrel of soldering iron from Collin of CS Guitars.
You could do NASA-spec solder joints if you want, but this is typically more than strong enough for connections. As for the resistor, it doesn’t really matter which leg you attach it (that is, before or after the LED in the circuit) as it will have the same effect. However, by definition, current will only flow through a diode in one direct, so it does matter that you have the LED leads clearly identified. That’s why I try to be consistent with using red as the positive (and typically black for the negative, but I was out of black hook-up wire during this particular project).
My garage is sort of organized, but it’s covered in dust. I knew it was getting bad and so I ordered a relatively inexpensive air filter for shop spaces. I’d had my eye on the WEN 3410 3‑speed air filter for a while. Home Depot has the best price for this item, but it’s routinely out-of-stock. It came back in stock in February so I ordered one then. It arrived, I plugged it up just to make sure it worked, and then it sat on my workbench for the past 6 weeks or so.
I had purchased the necessary hanging hardware a couple of weeks later, but still didn’t get around to hanging it up. You see, our garage has really high ceilings (12′-6″) and the dinky 12″ chains that are packed in the box weren’t going to cut it. The instructions state to hang it at least 7′ above the floor, but I’m pretty sure 11′ in the air isn’t going to capture a lot of dust. I purchased some pre-punched angle and about 20′ of 300lb chain. But still, this all sat on the workbench (ok, so maybe my garage is less organized than I’d like…).
So, today I finally decided it would the be the day to install this thing. And apparently none too soon. My son wanted to go over to his friend’s house but told me he didn’t want to ride his bike because it was covered in dust (he’s not wrong, but we got it down and aired the tires anyway).
So the angle I purchases was a 4′ section, and I needed to cut it in half. I also bought a cutting wheel for my angle grinder. This was actually the first time I’d ever cut steel with an angle grinder. I did wear a full face shield but didn’t cover my arms. The sparks were minimal, but I wouldn’t wanted to have cut several that way. I could have uses the same cutting wheel to cut the chains to length, but my bolt cutter was faster.
After that, it was just a matter of getting the angles lag screwed into the ceiling joists. I used some threaded quick links to attach the chains, just in case the unit started swinging around. That proved to not be a problem. Frankly, this was probably all overkill to hang a 31 lb unit, but it’s room to grow if I need something bigger.
I had to add an extension cord to get it plugged into the same outlet as my garage door opener and my retractable extension cordBy the way, the retractable extension cord is one of the single best items I’ve gotten for my shop. Between that and my rolling workbench, it feels like having a whole new shop area.. Then it was ready to test. Admittedly, this isn’t a very powerful air filter. At full speed, it’s 400 cfm. Fortunately, that’s not enough to get it moving hanging from hose 4′-6″ chains.
I don’t yet have much of a sense of how well it works, but it gets pretty good reviews. I’ll put it to the test soon enough by taking my air compressor to start blowing dust off of everything.
Most amps have the ability to use an external footswitch to change between a clean and distortion channel. Of course, some have more sophisticated options than this, but the channel switch is a pretty common feature. My older brother recently got an awesome-looking, orange Fender Duo-Sonic and a small Fender practice amp to play it through. This little Mustang amp has a lot of presets and he can use a footswitch to select between a pair of them. Of course, it being an affordable practice amp, the footswitch is sold separately.
But a footswitch is a pretty easy thing to make yourself. In my case, I had the double pole single throw (DPST) footswitch taken out of my Dunlop Wah pedal when I modded it (post to come someday!) and an old stereo audio jack. That, a bit of wire, and something to put it in is all you need! In fact, the fact that it was a double pole switch and a stereo jack made them both overkill for this small project! But why not recycle the parts for a good cause?
I purchased a powder-coated 1590LB enclosure from Mammoth Electronics. At 2″ by 2″ by 1″ tall, this is about as small an enclosure as you can get, but plenty big for a small switch and a jack. I got the orange to match his guitar (well, as close as I can get with stock powder coat colors, anyway). I laid out the switch and jack to ensure I could arrange them how I wanted; though I could have also just had the jack on the “side” of the enclosure. The circuit soldering here is super-simple: just solder the “tip” lug of the jack to the center lug of one of the poles (three of the lugs in a line make a pole). Then solder the “sleeve” lug of the jack to either the left or right lug on the same poll of the switch. That’s it! Did you mess up and wire the sleeve to the center lug on the switch? It’s still fine! All this does is connect the tip to the sleeve when the switch is “on” and then breaks the circuit between the two when it’s off.
Now, this particular build relies on an instrument cable to connect the footswitch to your amp. But you don’t have to use a shielded cable for this as the guitar signal itself isn’t passing through that cable; just a relatively low voltage (around 4–5v1) is flowing through to tell the amp the gain channel should be on. So you could actually skip the jack and just use any old wire (speaker cable, a lamp cord, etc.) and wire that into a 1/4″ audio cable end. I was just using as many spare parts as I could. In fact, I finished the bottom by cutting up a kitchen jar grip pad and gluing it to the bottom with spray adhesive (it won’t slide on his hardwood floor!).
Given that the Fender single footswitch costs around $15, this probably is not much of a cheaper alternative. But it was a fun gift for my brother and if you’re interested in practicing some soldering, this is a great and practical project to start with!
So, amazingly enough, there’s a video in which YouTube channel MerwinMusic makes the exact same footswitch as mine — down to the orange color! Check it out! He also does a great job of explaining how to test out that this sort of switch works with your amp before you go to the trouble of building one, which is a good idea as some amps may vary (but all good amps just copy Leo’s original!).
The voltage is low enough that my Blackstar head’s footswitch doesn’t even have a resistor on the LED. [↩]
With each new pedal build, I try to focus on some aspect that makes it a new challenge or something new to learn. My first pedal build ever (about 18 months ago) was a boost pedal. I decided I’d build another boost: this one using the MXR MicroAmp circuit. I used the General Guitar Gadgets MAMP PCB, which in addition to selling the PCB sells entire kits and has excellent documentation1. Since it’s a relatively simple circuit and, therefore a fairly small PCB, I wanted to try to fit it into a “mini” enclosure (i.e., a 1590A format). This means having to really think ahead about aspects of the build so that everything can squeeze into such a relatively small enclosure.
The first thing is that this pedal format can’t utilize a battery for power; the pedal will be AC powered only. That’s fine as I don’t use batteries in any pedal anyway and only ever added a battery snap to that first pedal build. Secondly, the height of the components really matters. The taller components (generally, the capacitors) had to be bent over. For the electrolytic capacitors, I had to remove and replace a couple in order to facilitate this (I had planned ahead otherwise — as my sketched notes on the wiring diagram shows below, but I am just so in the habit of soldering the completely vertical I forgot!). In the end, the tallest component off the PCB was the integrated circuit (IC), as it was mounted in a socket. This way I can potentially swap out ICs in the future. Speaking of ICs, I went with a low-noise TL071 op-amp (in place of the original pedal’s TLo61 — which consumes less current but, again, I’m not using a battery so I don’t really care about that). The only other modification I made to the GGG circuit was that I swapped out a 10MΩ in place of the 22MΩ pull-down resistor (R1). Really, any fairly large (<1MΩ) resistor value will do here and 22MΩ are a little harder to find.
Lastly, the arrangement of the larger off-board components such as the footswitch, jacks, LED bezel, and pot really came down to millimeters. I had to use calipers to measure every last item and meticulous sketch it out on a printout of the enclosure. I still managed to mess up drilling one of the jack holes (I located it 1/2 the diameter off, which s about the worst place to mess it up!). I was able to re-drill the hole thanks to having a drill press and some clamping blocks. It’s a bit ugly and the jack’s nut is a bit crooked, but it worked out fine.
The pedal works great. I mean, it’s about as simple an effect as you can get. It simply takes the guitar signal and makes it a lot louder (probably around the order of 20–25db). I’m pretty pleased with how clean the wiring worked out, as well.
My build cost around $27 for the parts I had to purchase. That’s not including resistors, capacitors, diode, and LED (nor hookup wire and solder), all of which I already had in my parts bins but would run you around $3 in total. I also had to pay around $9 in shipping. The PCB from GGG for was about $3.50 to ship. I bought parts for several builds at once in a large order from Mammoth Electronics (my parts supplier of choice), but smaller orders from there tend to ship for around $5. They have high-quality powder-coated enclosures for really great prices, along with generally good prices on other parts and kits. So, in total, this build is roughy around $39 in cost (and I still haven’t added any artwork, so consider what slide decal or other format might cost).
That being said, unless you really want to build your own, I would not recommend this build to anyone else. You can purchase a TC Electronic Spark for about $35 used on Reverb.com (plus shipping) right now. It has the exact same size as my build, but has their amazing non-latching (relay) footswitch and essentially the same amount of clean boost. If you don’t care about size, you can purchase a used MXR MicroAmp for around $49 on Reverb (plus shipping). Both of those are solid choices if you really just want a boost pedal and are less interested in practicing your soldering skills or learning how to layout a small pedal form factor. And honestly, as much as I think this pedal sounds great so far, those probably sound even better and have less noise at full gain.
But overall, I’m pleased with this build. On the clean channel, it just gets louder without adding anything else noticeable. Best of all: with the knob set to about 3 o’clock, it makes my Blackstar HT-5R head’s gain channel absolutely breathe fire!
I think I could have pretty easily build this circuit on perfboard, but probably not to fit in the this small of an enclosure. So for a bit more cost I opted for the PCB, which has a fairly small footprint. [↩]
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.
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 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!
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. [↩]
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.
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 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.
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.
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.
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.
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).
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.
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).
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.
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.
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.
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.