Wyatt & I went to the Nashville SC match with Memphis 901 FC tonight. We attended with his Cub Scout Pack and got to sit in one of the field level suites. The game was rain delayed an hour and there was rain on-and-off during the game, but we stuck it out. Mostly because, as part of the suite package the group got, we got to go out on the field and shoot a few goals after the game. Most of the families & kids had left due to how late it had gotten, but we stuck it out. Wyatt got 2/3 shots and I missed my one shot (trying to shoot for the corner). Still, was a really fun experience and glad he & I got to do it.
This project has been “in the works” for a while. I’ve had the pedal working for sometime but finally got around making the modifications to make it a modern pedal.
Let’s start with a bit of backstory: Last summer, my wife and I were helping to clean out my late father-in-laws tool shed. He had a lot of stuff and a lot of that stuff was entirely random. One such item was a late 70’s Electo-Harmonix Small Stone phase shifter. It was in decent shape, but upon opening it, the 9v battery corroded and ruined the battery snap. So it was unusable as-is. There’s not a definitive way to date it, but the pot is labeled 1377825, which means it was manufactured the week of June 19th (25th week) of 1978 by CTS (manufacturer’s code 137). So the pedal was likely build and sold in late 1978 or 1979.
The Small Stone is the other phaser sound from the late 70’s, where as the MXR Phase 90 is the one that Eddie Van Halen made famous (I have some theories on why that might have been, too.). That being said, it’s a great sounding phaser. I’m not a fan of the color switch on, personally1. But with the switch off, the effect has got a rich, space-y sound. This particular pedal just needed a bit of love.
The first thing was to put in a new battery snap to power the pedal. This pedal had a 1/8″ audio jack-style power jack. There are adapters for using this with a modern, Boss-style (2.1 mm barrel) DC power plug. However, it was a pretty simple operation to just drill out the case a bit larger and install a modern power jack. That got the pedal working again and how it stayed for about a year. And it sounded great.
Well, except for one issue and it’s why I think this pedal was never nearly as popular as the MXR or, for that matter, many of EH’s other pedals such as the Big Muff π. That is there is a serious volume drop when the effect is on. Imagine Eddie Van Halen turning the effect on for the drop-C# chug in “Unchained” and then back off for the chord progression. The riff would be ruined! 2. So I really wanted to fix that. Fortunately, 40+ years of history with this design and folks have figured out ways to address the issue. There are two resistor values that can be changed that dramatically improve the volume drop. I swapped out R11 and R42 and a quick test (outside of the case) saw the issue improve dramatically.
The bypassing mechanism on this pedal was fairly transparent. I personally can’t tell much of a difference when it’s in my signal chain or not. However, I did decide to make it a true bypass pedal along with the other mod, mainly just to add an indicator LED. Though I’m not a serious guitar player and never actually play live (or record), I do like having indicator lights on effects. If nothing else, it just reminds me to turn them all off when I’m done playing for a bit as a break during work hours! The updated switch, even just a cheaper “Taiwan blue” is still a lot less of a “ka-chunk!” than the old switch, too.
The last step was to drill out the hole for the LED bezel. Drilling steel is a bit harder than aluminum. I used a step bit as usual, but cutting fluid is a must in this case. Unfortunately, a couple of steel shavings scratched rings around the opening as I was drilling. I can probably buff them out, but a simple piece of painters tape would have protected the surface when drilling (and I usually think of that when it’s a powder-coated enclosure!). I boxed up the effect, plugged it in, and SQUEAL-EEE-OOO-EEAAA! Turns out, the output jack can rotate just a bit and short out on the color switch connectors. A small piece of black electrical tape fixed that, though.
Reverb has these vintage v7 Small Stone pedals going from between about $150 to $200, depending on their condition (they retailed for around $80 back in the 70’s). Even non-functioning, this one could have sold for $75-$100 (which would have easily covered the cost of a modern “Nano” re-issue model). So did I reduce its value? Maybe. Maybe not. There are some modded Small Stones also sold on Reverb going for even more. Many of those have additional controls added or the ability to attach expression pedals or other more significant modifications.
However, none of that is really the point for me. I think it’s really cool that this particular one belonged to someone in Angela’s family (most likely her late uncle, John, who played guitar some). I think of all the effects in my collection, this would be one I’d never really want to part with anyway. It’s got some real history; used by people I knew. And it’s been fun to take it and make it hopefully even better than before. It sounds great and though it may not have been the phaser I would have bought otherwise, it’s even better to me.
Some notes on that demo: first of all, it’s just recorded from my iPhone X on a tripod (as if the leg wasn’t the giveaway). The iPhone attempts to level out sound, so trying to show that the volume doesn’t drop when the pedal is engaged in this recording isn’t too useful. Next, even though you can clearly hear the switch clicking, it’s truly just because the amp volume is relatively low. There’s no pop through the amp. Lastly, I’m barely passable at playing this riff and trying to coordinate the pedal on-and-off with it was a particularly challenge for me.
The color switch seems to add second layer of phasing at a slower rate than the first so there’s a weirder change amplitude. I think this was more popular with organ and electric piano players than guitarists. I certainly can’t think of any recordings where I may have heard that color switch effect. [↩]
I’m not saying EVH ever actually even used one of these… In fact, after about 5 min of research, EVH actually used a flanger rather than a phaser for that particular song; but he did and does famously use a phaser for other songs such as Ain’t Talkin’ Bout Love), but for anyone who did they surely would have noticed the volume drop. [↩]
For the moment, CNN’s headline is about grad student Katie Bouman who helped accomplish something extraordinary because she’s really brilliant. The world’s pretty messed up, but for its great to see smart people get famous for awesome things.
[Addendum: Dr. Bouman gave a TedX Talk a couple of years ago on how a computer scientist such as herself ended up working on a globe-spanning astrophysics project and how the her imaging algorithm would eventually help make the image possible.]
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. [↩]
Our nephew, Keith, invited us to one of the The Escape Game adventures. These are really popular and I can see why. Anyone who was a fan of point-and-click puzzle computer games (like me) would love getting to be inside the game and that’s exactly what this feels like. My older brother, Stephen, and Keith’s fiancé, Jamie, joined us and we had a great team. We were able to divide up for different tasks and finished with over 11 minutes to spare for our Mission to Mars adventure. The entire facility is really nicely done and it’s easy to get caught up in the fun and pressure of trying to solve the puzzles together in under 60 minutes.