EarthQuaker Devices Hummingbird Tremolo On Stripboard

If you take a look at the list of all the guitar pedal stripboard layouts I’ve made for this site, you’ll notice that there are quite a few distortions, fuzzes, and overdrives. I like building dirt boxes, and I’m always fascinated at how different they sound, even with similar circuits. But recently I’ve done something different: a tremolo pedal! This specific tremolo pedal is the Hummingbird by EarthQuaker Devices.

I chose EarthQuaker Devices’ Hummingbird because it looked like a good no frills tremolo pedal, it sounded good, and I’ve liked other EarthQuaker Devices builds I’ve made. So why not make the Hummingbird?

I don’t have a lot of experience with modulation style guitar pedals outside of kits, so I also figured starting with a more basic circuit would be a good idea. Sure, that building process is the same, but I wasn’t sure if building something different from what I’m used to would be less forgiving. This was a pretty cruisy build though.

Before I launch into the usual breakdown of the schematic and the stripboard layout for this pedal, for those less familiar with effects pedals, I think it’s worthwhile talking about what a tremolo is and what is does. As the name would suggest, a tremolo pedal makes a tremolo effect. This effect is a rapid change of volume giving a kind of shimmering sound to the notes being played. Think sounds you here in Surf Rock, especially something like Misirlou by Dick Dale. A tremolo is different from a vibrato pedal in that vibrato changes pitch rapidly. Both great and interesting effects, but they’re different to one another!

If you want to learn more about the circuit for the this tremolo pedal, read on, otherwise just skip ahead to the stripboard layout.

Jump to stripboard layout.

EarthQuaker Devices Hummingbird Wiring Schematic

EarthQuaker Devices based their Hummingbird on the Vox Repeat Percussion tremolo system with, according to them, some updates to reduce noise and increase control. Although I’m less familiar with tremolo circuits, I’d hazard a guess that this is a pretty classic/basic tremolo circuit if they’re basing it on something old.

The basis of a tremolo circuit relies on the principles of building a low frequency oscillator (LFO). I’ll do a separate article on LFO’s in the future – I need to do some more research in order to adequately explain them – but the basic explanation is the circuit changes the voltage output, and therefore the volume, of the signal. Do this quickly and you get a tremolo sound. And of course you can adjust how quickly the voltage changes to adjust how quickly the tremolo is done. If you’re unsure about why voltage controls volume, take a look at my article on how volume knobs work. That will explain it.

So, unless you want to read further on LFO’s, just accept that that’s what the circuit is doing. When you adjust the “rate” potentiometer, you’re adjusting how quickly the change in voltage (and therefore volume) happens.

Here’s the wiring diagram:

Click on the schematic to enlarge it.

And here’s the bill of materials.