RK EVENT Eurorack Modular Build

Rat King Modular - EVENT DIY KIT

For the final build of June 2019 we took on the Rat King Modular EVENT, which to our surprise was a hidden gem for our eurorack system. The EVENT is the first eurorack module by Rat King Modular and we have to say, it’s a little beast. The panel is beautifully designed and the layout of the knobs and the jacks makes the EVENT easy to maneuver while recording or performing.

The matte black design with gold highlights is backed by a mustard yellow PCB who’s layout is easy and concise to follow. The dual sided PCB accepts solder like a sponge which makes this build a hassle free and not to mention fun build. So lets get onto the build…

Time Lapse and Build Notes

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For this build we used several different helping hands so that we could maneuver effectively throughout the build. The resistors and diodes were soldered top-down so that we could easily trim the legs.

We used the BOM as a guide and double checked the resistors in our handy dandy tester so that we ensured that each resistor was placed accordingly. Upon completing the resistors and diodes, we jumped into the ICs, power header, caps and transistors.

Pay special attention to the transistors and make sure they are oriented in the correct way. One flipped transistor or a transistor that is not where it was designed to be will cause some unwanted results. 

The scale knob was next which takes us to the other side of the PCB. Make sure to follow the assembly instructions and mount it in the correct position. If you mess up on this step, the panel will not fit the module correctly and you will find yourself desoldering before you know it. 

After the scale know, it was onto the jacks and potentiometers. You can place them on the board, but DO NOT SOLDER immediately. The pots have different resistance values so it’s important to not get these out of line. Just refer to our photo if you need guidance or you question your build.  Drop in the two LEDs and make sure you get their polarity correct. 

After placing the panel on the jacks, LEDs and pots, use the supplied nuts to tighten down a few of jacks/pots and then flip the board over to solder everything into place. Trim the legs off the LEDs after soldering and then you are almost done. Tighten everything down and place the ribbon cable correctly into the power header. The black Davies knobs are next, which complete the module and prepare it for use. 

That’s it … the EVENT is complete and you are now ready to plug it in and experience what a wonder it is.  So now that you have it completed … what is the Rat King Modular EVENT and what does it do? 

It’s a VCO, envelope, slew limiter (portamento), waveshaper, LFO, and envelope follower all in one! That’s what we said… all in one module. Kits are 65$ and fully assembled EVENTs can be purchased for 115$ over on the Synthrotek store page. (links are below)

EVENT Promotional Flyer

Controls and Specifications


  • ONSET: Controls the positive rate (time) of change in voltage. It has a bipolar CV input jack.
  • DURATION: Controls the negative rate (time) of change in voltage. It has a bipolar CV input jack.
  • HEIGHT: Controls the held voltage level when a continuous gate is applied.
  • TRACK: 1v/oct input. It is particularly useful when patching the EVENT as a VCO.
  • START: A simple gate/trigger/pulse input that initiates a cycle when the EVENT is patched as a voltage controlled envelope.
  • SIGNAL input: Can be a constant or fluctuating voltage. This input is particularly useful for mangling CVs.
  • SIG OUT: The main output, the result of the gate/trigger/pulse input or SIGNAL input.
  • PLS DLY: A short pulse used for triggering other events as pulse delay (or as self trigger when patching the EVENT back into itself).

Power and Specs:

  • Module width: 8HP
  • Module depth: 22mm
  • Current draw:
    • +12V: 50mA
    • -12V: 43mA

RK EVENT - Audio Sample

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Purchasing Information

Panel and PCB Combo

  • Black Matte Panel 
  • Mustard/Gold Dual Sided PCB
  • List Price: $25.00 USD
  • Click on the image to be redirected to the Synthrotek Store Page


  • Includes all components, PCB and Panel for assembly
  • List Price: $65.00 USD
  • Click on image to be redirected to the Synthrotek Store Page

Assembled EVENT Module

  • Fully assembled and calibrated 
  • List Price: $115.00 USD
  • Click on image to be redirected to the Synthrotek Store Page

Rat King Modular EVENT - The Final Word

Overall Rating:

In the end, this was a fun kit to assemble and upon patching into the EVENT. Simply put we need another one or two.  (Did we mention you can patch one EVENT into another?) For the price, features and aesthetics of this module, there is no reason not to have more than one. Hands down, this is a badass module. 

If you have questions or comments about the Rat King Modular EVENT, please feel free to reach out to us via our Contact page. If you would like to pick up the EVENT, click on the links below to head on over to Synthrotek (it’s exclusive) and let them know that we sent ya!

Until the next build … 

~ f i N

Completed EVENT build