Tag: DIY

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!).

1. 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!

1. 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!

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. [↩]

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.

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.