Haraldswerk ADSR

I have build a few of these and use them quite a lot. I have some spare pcb’s and panels in my drawers to build even more of these. (If you looking for a set contact me). The ADSR does what it should do and like most of Haralds design it very well designed. Harald based his ADSR on an Elektor Formant ADSR schematic. It has pretty good spec’s, if you want to know more about this one be sure to check out Harald’s website.


Difficulty to build: Easy

Haraldswerk Mixer

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/


Difficulty to build: Easy

MXMXMX Temps Utile

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.


YouTube review (not my video)

Difficulty to build:

SMD parts

Skull and Circuits VCF-3

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.


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

Skull and Circuits The big Bass Machine

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.


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

ST Modular Dual LFO

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

Extralife SuperSixteen Sequencer

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.



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

3uShop Multiple

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.


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

Kassutronics ASR

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.


Difficulty to build: Easy / Medium

Kassutronics VCO 3340

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.


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