Erica Synths Modulator II - DIY Build

Following our last build of the Erica Synths Mixer II module, we decided to go back to back by taking on the Erica Synths Modulator II. This DIY module is essentially an LFO with simultaneous triangle and square wave outputs. It is a clockable S&H module with external CV input and noise source. It is also one of the new kits currently being offered by the gang over at Synthrotek.
Apart of the DIY series from Erica Synths, the Modulator II is unique in that it not only has one noise source, but two. Noise sources come in the form of “backpack” PCBs that one can swap for different tones of noise. You have the choice of transistor-based or Zener diode-based noise generator for massive, full spectrum white noise.
As you start this build, it can easily feel overwhelming upon cracking open the kit being that there are multiple PCBs and a bunch of components. Synthrotek did a great job on this kit by providing a clear BOM which we have scanned and linked below. They also separated all of the components for each backpack PCB so that the parts could be located quickly and partnered with the correct board.
IMPORTANT: Before we jump into the build, take note that this is not a build for novice builders. This is due to the very tight soldering pads, poor layout of the silkscreen and one’s ability to read a BOM. You do not want to go into this build not knowing how to read or build from a BOM, being that there is little to no step by step assembly instructions.
The Erica Synths assembly guide is really generalized compared to most DIY build guides we have seen from other companies (but hey, thats why we are writing this up and recording our videos).