Tag: VCA

Synthrotek VCA – DIY Build

Synthrotek Crossfader (CF) and 2hp Buff Mult - DIY Builds

We all know that you can’t have enough VCA’s in a modular system. The gang over at Synthrotek recently released a new VCA module in their slider series and we had to pick one up. This kit is different from most of the other Synthrotek kits we have assembled in the past, in that it is an SMD kit. With that being said, this module and/or build is not for the novice builder. 

You will want to have a few hours of practice on SMD before jumping into this one. 

The slider series by Synthrotek looks great and along side the other slider modules, the VCA fits right in. As with most SMD builds, we generally use a digital microscope, but on this build we did not. We not only used our normal 60/40 solder but we also used solder paste on some of the build. Let’s get on with the build shall we?


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. 


Waveform Magazine Meow Mixer (Project 6) – DIY Build

Waveform Magazine Meow Mixer - DIY Build

Completed Meow Mixer - Front

Every quarter we receive a new issue of our favorite magazine… Waveform. In this issue (Summer 2021 – Issue 6), a small 2HP module called the “Meow Mixer” was featured alongside a new modular case kit (aka. The Mewsic Box) as the featured project. The Meow Mixer is a 3-channel powered Eurorack module that has 3 inputs with attenuation, and 1 summed main output with an output volume control.

As with every DIY project that Waveform Magazine releases, the Meow Mixer was unique in that it could be used in conjunction with other DIY projects that Waveform released. This sounds confusing we know … but stick with us on this build and we will explain everything in detail. So, without further ado, let’s jump right into the build of the Waveform Magazine Meow Mixer!


Waveform Magazine Catwalk LPG/VCA – DIY Build

Waveform Magazine Catwalk Cattenuator - DIY Build

As we tackled the Waveform Magazine Cattenuator, it was now time to tackle the new LPG/VCA. Like the previous build and the Mini Mult Catwalk, these modules take up about 12HP of space in your rack. Their footprint is small and their impact is huge. As previously stated, Waveform Magazine is on point with their Catwalk series. In case you have missed any of the previous builds or reviews, check out the quick links below to learn more.

Project #5 - Catwalk LPG and VCA

Let’s get onto the builds shall we? Building the Catwalk VCA or the Catwalk LPG is relatively easy. The most difficult part of this build is assembling the vactrol or optocoupler as its sometimes called. An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical signals between two isolated circuits by using light. 

You will be putting together 2 of the optocouplers for this set of Catwalks, so turn on your iron and get ready to dive right in. 

Quick Links: