Category: DIY

This mixer I tend to use as my final mixer before sending it to a output module like the Erica Synths Output or my Expert Sleepers ES-9. The nice thing about this module is has a led indicator. The led turns on when there is to much signal going into the mixer. The mixer also has an inverted output and is DC couple so it can be used for audio and CV signals.

for panel gerbers: https://www.quinie.nl/panel-haraldswerks-dc-coupled-mixer-with-volume-indicator/

https://www.haraldswerk.de/Mixer/Mixer_Euro/Mixer_Euro.html

Difficulty to build: Easy

Many people use this as a master clock module. As I have a few LittleBens in my rack I tend to feed it a external clock and use it as a drum trigger sequencer. It show how many possibles this modules has for a eurorack setup. I was my first clock module before I build my own clock. The only part I didn’t like about this one when using it as a clock was that I could not read the BPM very well. You also need to do some menu diving to set all parameters. That’s just me complaining a little bit cause I would want to miss this in my rack. Overall a very very good module to have.

https://github.com/mxmxmx/temps_utile-

YouTube review (not my video)
https://youtu.be/YEXRavDMt2o

Difficulty to build:

Hard.
SMD parts

Another filter based on the LM13700 chip. A lot of filters use this chip and have similair designs. I have to double check the schematics on the skullandcircuits.com but this could be based on the MS 20 design by Korg (didn’t check yet when posting this). It has it’s own sound that’s one reason to put this in your rack. It has lox pass, band pass and high pass outputs that enable mixing them together with a mixer.

https://www.skullandcircuits.com/vcf-3/

Difficulty to build: Easy.
Not that many parts and well spaced.

This module I build a few months ago. I’m still experimenting with it. It makes great bassline’s. I don’t know yet if I have calibrated it enough but it sound awesome even without. When I have played enough with it I will surely update this post. But if you are looking for a module that can produce deep basslines, give this one a try.

https://www.skullandcircuits.com/big-bass-machine/

Difficulty to build: Hard, because it has a lot of parts.

After building the 3uShop Multiple in my reflow oven I went on a reflowed this module. It’s a dual LFO by ST modular. It’s small and compact with two LFO. It can go pretty fast. Everything depends on the values you choose for the capacitors driving the LFO’s. I like this one because it so small and I can fit it nearly anywhere in between in my rack.

The only thing I really hate is the support forum for this is on facebook. And I don’t/want to have facebook. For this module that wasn’t a big deal cause it worked straight out of the oven. But I do have two of ST modular modules in my repair box, waiting for repairs.

Difficulty to build: Hard, SMD parts

I was in need for a sequencer. Then I found this module by Extralife. It’s a nice step sequencer that I use a lot. Maybe also because at this moment it’s the only sequencer I have in my rack. I build two of these. You can but this module build but the files to DIY are available on Github also. As I figured I didn’t need more then two I traded the spare pcb’s and panel for other pcb’s. I still have to figure out all the function cause I think it can do more then I currently use it for.

https://store.extralifeinstruments.com/products/super-sixteen-eurorack-sequencer-module-complete

https://github.com/matthewcieplak/super-sixteen

Difficulty to build: Hard, Just because of the W25Q80DV chip that’s pretty small.

When I received my order from 3u Shop there was a extra module in the package. This multiple was one of the first modules I build with my reflow oven. It was small enough to test the oven and with me having to spend a lot of money on parts. Any multiple in your rack can be nice but this one is buffered. Meaning it can also be used for multipling pitch CV’s. I work straight out of the oven so pretty happy with the results. Thanks 3uShop for adding it to my order.

https://www.3u-shop.de/p/3u-shop-buffered-multiple-1to6

Difficulty to build: Hard /Medium
SMD, but this could be a good start for experimenting on SMD

This is a nice and small ASR module. Normally you would call this a ADSR module but Kassutronics left out the decay part and knob. He uses the ADSR in a way where the decay and release are often set the same. Therefor Kassutronics combined these two under one knob. The ASR can also loop and can be used as a sort of LFO. It’s a nifty little module. Again with the white panel made from wood. I have had to fix it once where the gate wouldn’t work anymore and the loop function did. I was a minor fix the bottom TL072 broke so have to keep a eye on that one.

https://kassu2000.blogspot.com/2018/10/asr-envelope.html

Difficulty to build: Easy / Medium

Just another 3340 VCO. This chip is used in a lot of VCO these day’s. The CEM3340 chip was achip used in a lot of older synths like the Roland SH-101, the Sequential Prophet 5 (Rev.3) and more. Electricdruid.net has some schematics and more background information on that online https://electricdruid.net/cem3340-vco-voltage-controlled-oscillator-designs/

The CEM3340 VCO chip has been re-released. It has also been cloned by CoolAudio as the V3340 and by Alfa as the AS3340. You can put any of these in the VCO 3340. I think I’ve put Alfa version in mine. But have to double check that.

It’s a nice and small VCO by Kassutronics and sounds pretty good.

https://kassu2000.blogspot.com/2018/06/vco-3340.html

Again would have liked it if Kassutronics would offer black panels. So If anyone knows where to find those please let me know.

Difficulty to build: Medium

This was one of my first filers. It’s based on the famous Korg MS 20 design. I believe it’s based on the late design by Korg. I’ve been looking into filter designs a lot lately and this one is really nice. A good description can be found on Kassutronics site: https://kassu2000.blogspot.com/2019/07/ks-20-filter.html

He based the filter on a design by René Schmitz. René did a lot of reverse engineering to find out how the filter in the Korg worked. Most of the MS20 filter design in eurorack are based of the schematics René posted. https://www.schmitzbits.de/ms20.html. There is a nice write up by Tim Stinchcombe about the korg filters. If your into some more background stories check out his website too https://www.timstinchcombe.co.uk/index.php?pge=korg

I enjoy this filter it can scream a lot. The only thing I didn’t like is the panel. I like to have had a black panel for this one but that doesn’t seem to be available. If anyone does know where to find a black panel for this please let me know. If you order this on Kassutronics site make sure to peel of the panel protector a lot of people have mailed him the text looks faded. The protector needs peeling off.

I do have a second one in my rack that is based of Kassutronics schematics and made by a good friend of mine. So there are a lot of MS 20 filters out there I think it might even be the most build filter in eurorack.

Difficulty to build: Medium, Good manual