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