Tag: Erica Synths

Erica Synths Polivoks VCO – DIY Build

Erica Synths Polivoks VCO - DIY Build

ES VCO - Boards 1

Erica Synths have been around for awhile and while most of their previous offerings in the modular world were fully built modules, they do have some DIY kits. The Erica Synths Polivoks VCO or Voltage Controlled Oscillator is one of those modules. 

The core of this VCO is borrowed from the famous Russian synth Polivoks VCO, and original matched transistor IC is the same of that was used in Polivoks. These two things give this VCO a very well rounded and beefy sound. (We liked it so much we have 2 of these). 

The gang over at Synthrotek have made these kits available in all their entirety. They have several options available to purchase (links below), including a fully assembled module if you do not feel like building anything. We opted for the full DIY Kit as usual and began warming up or irons!


Erica Synths SWAMP – DIY Build

Erica Synths SWAMP - DIY Build

The Erica Synths SWAMP is a random CV and audio generator inspired by the famous Wiard Wogglebug module; it’s often the heart of self-generating patches and brings controllable randomness to any modular system.

Synthrotek did the world of DIY builders a solid by putting together these hard to find discontinued kits, and we have been wanting to get our hands on the SWAMP for a long time…and now you can too!

Purchase Quick Links: 

Erica Synths SWAMP – DIY KIT

Erica Synths SWAMP – Fully Assembled

Erica Synths SWAMP – Panel/PCB/IC

Before hoping straight into the build, let’s take a step back and highlight what separates this module from the original Wobblebug. 

The Erica Synths SWAMP module introduced numerous modifications and improvements to extend the potentiometer range. It added an audio input, which, when connected, replaced the internal Tone oscillator, and the expensive dual vactrol.

The S&H (sample and hold) circuit was build around the Riga S&H IC (AS1100CK2) and ES added audio waveform selection switches, CV output configuration jumpers and much more. All of these are reasons to have just one in your rack!

To sum everything up, the Erica Synths SWAMP is an advanced multi-level kit that can pose a few challenges for even the experienced builder. Packed and distributed by Synthrotek, the entire DIY line of modules is now available for you to take on! (so we had to)


Erica Synths Dual VCA II – DIY Build

Erica Synths Dual VCA II - DIY Build

Completed Rear - Dual VCA II

On with the build....

Fresh off the build table comes Erica Synths Dual VCA II. The module itself is apart of the open source DIY kits that are available via the Erica Synths Github.

Our friends over at Synthrotek have painstakingly taken it upon themselves to part out these kits and package them up to make them accessible by all DIY enthusiasts. VCA’s or voltage controlled amplifiers are modules that every rack contains.

This module is a Polivoks-inspired VCA that is 35mm deep, skiff friendly, has solid mechanical construction and doesn’t require wiring.  Who could pass this one up? We couldn’t! 

In the end, the Erica Synths Dual VCA II is like all other kits in that the BOM is comprised of the basics … resistors, diodes, capacitors, pots and jacks. There might be a few other surprise components in there, but all in all, these are what make up the kit.

Start by laying out all of the components and the x3 boards. This kit contains a control board and a logic board so you will be going back and forth between the two boards when placing components. Resistors, diodes and ferrite beads are first up.

Diodes have polarity so prior to tacking these down, you have to make sure they are placed in the correct orientation. We used top down soldering to make quick work of these. 


Erica Synths Output – DIY Build

Erica Synths Output - DIY Build

As the world of modular continues to grow, there is one module that is a must for any rack or system…. the output module. How else are you going to get your amazing performance to your speakers or interface to record? 

Erica Synths have been around a long time and their eurorack kits give DIY enthusiasts a chance to build their amazing modules. Their open source modules were previously discontinued and hard to come by until recently.

Packed and distributed by Synthrotek  the entire DIY line of modules is now available for you to take on! The Erica Synths Output module is a quick and easy build and is an essential module for any system. 

Before we jump right in...

Erica Synths Output - Completed Front

Since you are dealing with two PCBs on this build, we highly recommend reading the assembly guide when you are putting this module together. Things can get tricky because there are multiple things going on here.