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

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