Tag: envelope

FRUKU Evi – DIY Build

FRUKU Evi - DIY Build

One of our favorite manufacturers, FRUKU is at it again with the release of his Evi module. In only 2HP, the FRUKU Evi is an envelope follower and signal inverter, meaning that you can plug any audio signal into the module and you will output an inverted envelope. What can this do? 

Well, it can add some spice to your signal routing and bring some flare to those beats you oh so desire. As one of our first builds of the fall season, the Evi was a perfect module for us to get our hands on. Let’s get on with the build. 

Links and more links…

Below are a series of links that have been provided by FRUKU to help assist with the use, building and buying of the Evi.

Of course, we are here for you as well if you have any questions while building the module. Just hit us up on our Contact Page.

Let’s get on with the build…


Erica Synths Polivoks Envelope Generator – DIY Build

Erica Synths Polivoks Envelope Generator - DIY Build

With October coming to a close, we decided to take on one more build for the month. This time we took on the Erica Synths Polivoks Envelope Generator kit by Synthrotek. We were lucky enough to get our hands on one of these modules being that the recent supply chains have been challenged. 

Many of the DIY kits are either sold out or components have been scarce. Upon getting the kit, we took a moment to review the BOM and Assembly Guide provided by Erica Synths and dove right in upon receipt of the kit.  


Synthrotek Quadrangle – DIY Build

Synthrotek Quadrangle - DIY Build

The Synthrotek Quadrangle is a quad cascading triggered envelope generator with bipolar output attenuversion and is 20HP module with a lot of versatility. With 4 cascading envelope generators and user voltage control over attacks and decay/release, this module is in a class all to itself. 

As the fall season slowly began creeping in, we decided to go back and see what kits we had left to build for the year. To our surprise, we totally forgot that we had the mysterious Quadrangle from Synthrotek up on our build wall. This was partially due to the studio remodel and the continuous go go go of daily life. 

The Kit...

When we opened up the kit, the first thing we noticed was the size of the boards. This was a BIG module. 20HP to be exact. It consisted of 2 PCBs and one panel. We ordered the kit with the black panel but Synthrotek also offers a silver panel. As this kit was a big one, we knew we where in good hands with the amount of build data there would be available.

Included in the kit was a printed BOM as well as all the components you need to complete the kit.

Intermediate to advanced builders will not have an issue with this build, whereas novice builders could struggle due to tight soldering pads. 


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.