Tone... In.... SPAAAACCCE!!! Cloning the EQD Space Spiral

Looking at the pantheon of available DIY effects pedals, you'll see a lot of distortion and overdrive pedals, a large number of boost and fuzz pedals, but then there tends to be a drop off as you get into modulation effects like chorus, delay, and flangers. Part of the reason for this is a lot of the classic analog modulation effects rely on long out of production integrated circuits, so even if you recreate the board exactly, you're missing critical components to actually make the effect work. There are, however, clones of many more modern pedals with modern integrated circuits, such as digital delay effects based on the PT2399 chip. One of these is the Earthquaker Devices Space Spiral - which can do anything from slapback delay, to a reel to real chorus, to absolutely psychedelic reverb and delay. It's not an incredibly expensive pedal, only about $199 new, but as there's a dearth of Steggo modulation pedals at this point, I thought it would be a good one to try out!

For this build I started with the PedalPCB Dark Rift Delay board. As with most of the PedalPCB builds, the board is tightly laid out with all of the components in rows. Generally I love this sort of layout because it makes soldering groups of resistors and capacitors much easier. This one even has ICs between the major passive component rows, which normally makes assembly even easier, but there is one glaring issue with the layout of this particular board - the spaces for several of the film capacitors are smaller than they should be.

Most commonly used box film capacitors with values of <100nF are 2.5mm wide, but as you start going to larger values, the width of the capacitor rapidly increases. As you can see from the board above, the Dark Rift board calls for several 1μF capacitors and one 330nF capacitors. All of these are commonly 3.5mm wide, not 2.5mm wide. On a loosely packed board, or if the component is at the end of a row, the 1mm difference in width wouldn't have mattered, but being tightly packed as they were, it made actually fitting the capacitors on the board difficult without having them extend above the height of the neighboring capacitors. 

So, to make everything work I first had to bend all of the legs of the 1μF caps to get them to into their allotted portions of the board. For the run of four capacitors on the left hand side of the board, I ended up using Panasonic 100nF capacitors (which are raised above the level of the PCB on their leads) so everything would fit. The 100μF electrolytic capacitors I had available were a bit large in diameter as well, but one fit fine as there was plenty of room to accommodate the larger footprint, and the other one I could just bend over the resistors.

Apart from the challenge fitting the capacitors onto the board, the rest of the build was very straightforward. The resistors are all 1/4W 1% metal film (a mix of Yageo and KOA Speer), the film capacitors are all WIMA and KEMET, the electrolytic capacitors are Nichicon. The ICs came from a variety of sources, but all of them are socketed. For the wiring, I'm following my more recent practice of having separate ground wires from the board to the jacks, and as this is a delay pedal, I wanted to make sure that the input and output wires could run along the edges of the enclosure. I also moved the location of the LED so there would be more room for art on the front of the enclosure.

As to the art, it's been a while, but this is another awesome dinosaur painted by my lovely wife ADK! According to Wikipedia:

"Styracosaurus is a genus of herbivorous ceratopsian dinosaur from the Cretaceous Period (Campanian stage), about 75.5 to 74.5 million years ago. It had four to six long parietal spikes extending from its neck frill, a smaller jugal horn on each of its cheeks, and a single horn protruding from its nose, which may have been up to 60 centimeters (2 feet) long and 15 centimeters (6 inches) wide."

I carried the blue from the dinosaur through to the top of the enclosure. Because there are six controls, I decided to go with smaller knobs as otherwise they'd completely overwhelm the design.

With all of the knobs, it is possible to get an extremely wide array of sounds from this effect. I've managed to match the sounds from the EQD site using their settings, so I know the pedal is functioning properly. If the repeats knob goes past around 3:00, the pedal will self oscillate. Ultimately this pedal does several modulation effects well, but getting it dialed in takes a bit of trial and error. Of course, that's half the fun!