noise embedded.

Modular Drum Machine? It was yet another boring afternoon at work. I ended up searching for some interesting DIY eurorack kits. I had never considered adding any drum stuff to my modular synth. I have the not so perfect Akai Howling Wolf drum machine in my setup and have been somewhat disappointed with the kick drum of the unit. So when I found the cheap  Sound Force 808 kick diy kit  I just couldn't resist. They also have 808 snare kit available so of course I had to get both. Weird-Valued Vertical Resistors I usually start all pcb builds by soldering the resistors. They are easy to install and are the lowest components. Unfortunately these boards are designed for smaller resistor components. They can be built with normal through-hole resistors but everything needs to be installed vertically. This makes soldering much slower and more painful. I have plenty of resistors and capacitors around and these boards don't use any exotic ICs so I thought I could build th...

The Very Beginning of the Signal Chain Voltage controller oscillators, or VCO's, are the root of everything in subtractive synthesis. That's the place where the sound is born and everything after that is just modifying it. VCO really creates the sound. It is also the component that defines pitch and thus makes melody and harmony possible. Rest of the signal path is mostly about timbre. (And rhythm of course.) I started my modular synth by building a Doeper DIY Synth so I only had one VCO. It really limited things so I had to get more. Things got a bit better when I added another Doepfer DIY Synth to the rack but 2 oscillators is still not that much. There's two reasons to add more oscillators. First one is to be able to play multiple notes at the same time to generate harmony. The second one is to configure multiple oscillators to play the same note to generate more complex sounds. Analog VCO's are always more or less out of tune so the sound will get thick...

Getting Rid of the Empty Panel Half As already mentioned in my earlier post , I started my modular synth with a Doepfer DIY Synth kit. It happened to take exactly one half of the 3 unit rack panel. It was clear that sooner or later I would need to add something there because the half empty panel looked somewhat silly. "Must fill panel! Must fill panel!" You might have noticed that Doepfer gives a rather nice discount promise in the DIY synth webpage : If you build one and send some photos to be added to the page you will get 50% discount for another diy synth board! (Or possibly an extension board in the future). After I had documented my modular synth beginnings into this blog I sent a link and some photos to Doepfer. Pretty soon I got a reply from Dieter Doepfer himself! You can spot my synth in the page now. At this point it was pretty clear that I would build another DIY synth to fill the panel. I had already been missing another oscillator and ADSR and thi...

More Modulation, Please! After I got the Doepfer DIY synth up and running I immediately realized I needed more than one low frequency oscillator to modulate things. In the current setup I can modulate oscillator frequency, pulse width, filter frequency, filter resonance, another filter frequency, amplitude of the VCA etc... So one LFO simply isn't enough! The Schematic Because of my "quantity over quality" synth building philosophy I started looking for a really simple and cheap LFO circuit that I could easily multiply. I finally ended to the ASM-1 DIY synth page.  That's actually one of the pages I spent a lot of time in ten years ago when planning to build a modular synth for the first time. ASM-1 is a complete modular synth but not exactly compatible with the current Eurorack format as it uses -15V/+15V voltage. After studying the LFO schematics it turned out that the LFO is really simple. The circuit is pretty much as simple as it can get. A Schmitt tr...

The Ultimate Form of Sound Synthesis I have been dreaming of a modular synthesizer for quite some time. All those photos of the early synthesizer studios with walls full of potentiometers and billions of patch cables running wildly everywhere have such a lovely mad scientist vibe that you just got to love those machines! Buying a ready-made modular synth has never been an option for me. Soldering everything together is part of the charm. I even started building one about 10 years ago and bought the components for a DIY oscillator and filter. I managed to build the oscillator on a vero board but it never oscillated and I somewhat lost the interest on the project. The biggest problem is that you have to build quite a list of modules before you have a synthesizer. Yes, you get sound from an oscillator right away but it's quite boring and useless until you add a filter, vca, envelopes and some modulation. Even if I had managed to get the oscillator working it would have requir...