Tag: filter

Waveform Magazine PT2399 Delay – DIY Build

Waveform Magazine Project 1 - PT2399 Delay Module - DIY Build

When it was announced that there would be a magazine dedicated to modular synthesis, you can imagine the feedback from the modular community. Waveform Magazine was born in the summer of 2019 and upon its release it created a following.

To much of everyones surprise, not only was this a magazine that reviewed modules, manufacturers, artists, etc.. it also contained its very own DIY projects.

Project #1 was a upcycled karaoke reverb PCB that would be transformed into a eurorack delay. Otherwise known as the PT2399 Delay or Waveform Magazine Project #1, this little 5HP module inspired a whole new group of DIYers due to its new found glory of being published.

Waveform Magazine PT2399 Delay Module

PT23.. what?

At the heart of Waveform Magazine Project #1 is the PT2399 chip. The PT2399 is a CMOS echo/delay processor developed by Princeton Technology Corp.

This digital chip includes an ADC (Analog to Digital converter), 44Kb of RAM to store the samples and a DAC (Digital to Analog converter). This chip was created as a simple solution to add delay/reverb/echo to karaokes and set-up entertainment systems. Pretty rad eh?

The PT2399 is readily available and has a minimum delay of 30ms and a maximum of 340ms (that could be extended up to 1 second at the expense of sound quality) which makes it perfect for delay, echo and reverb effects.

Waveform logo yellow

Sound Study KONTACT Mic – DIY Build

Sound Study KONTACT Mic - DIY Build

Stylized KONTACT Mic

For this build, we take on the Sound Study Kontact Mic Eurorack module. This 4HP module is a unique way to interact with your system on multiple levels. It’s creative applications are endless: finger percussion/rubbing/scratching, guitar input (works surprisingly well with just a little lo-fi crunch), acoustic sources to CV, etc.

While this module has been out awhile now, we wanted to pick up another mic source to add to our racks. The modules rad skull design along with its small footprint made it the perfect candidate!

Study what? Sound?

Sound Study Modular only produces a few modules or stand alone utilities. Along with the Kontact Mic, they are responsible for the MIDI 2 CV (stand alone or eurorack format) which we also use in our racks. Their PCBs and panels are solid and are black with silver accents.

As the MIDI 2 CV is a clone of the famous CVPAL, the Sound Study Kontact Mic is a clone of the MTM Mikrophonie. With that being said, we have both of Sound Study’s modules and we wouldn’t leave home without them!

Enough of the descriptions, let’s get onto the build


Synthrotek DIRT – DIY Build

Synthrotek DIRT Eurorack Module - DIY Build

Completed DIRT Module
Completed DIRT Module

A classic Synthrotek filter, the DIRT is a 4HP module that is a necessity in any modular system. We actually have two of these and forgot to do a build video for the first… so guess what we did? You got it, a time lapse build of our second little module with grit.

What is the Synthrotek DIRT? It is described as a low-pass filter or effect module for eurorack modular systems. It has three knobs all which coinside with different variables of tone/sound. It can be used for filtering, ring mod effects, wave shaping and even harmonic distortion (which you can hear in our audio samples below).

Let’s get on with the build shall we?

How hard was the build?

The Synthrotek DIRT is a pretty simple build actually. It took about an hour to complete with a few stops along the way to change the tunes and grab some knobs for customization. 

One thing you want to make sure to pay attention to is the polarity of the caps (as usual) and the values of the potentiometers. There are only three pots, but all three have different values. The nice thing is that Synthrotek provides a great assembly guide and packed BOM for your reference. When referring to the assembly instructions, you will find that there are actually three different versions of the Synthrotek DIRT. A 9V standalone version (for pedals) and 2 eurorack versions are available. (At the time of this review, PCB version 2.2 is the current version). 


Synthrotek Octave Fuzz – Time Lapse Build

Synthrotek Octave Fuzz - Time Lapse Build

For our first build of 2019, we take on the Synthrotek Octave Fuzz module.  You ask why we chose this module? What attracted us to needing this module in our rack?  Well the answer is simple… that 1970’s fuzz sound that you rarely hear in music these days.

Combined with the ability to trim the octave and gain on the back of the module opens up a whole new slew of sounds. The 70s never sounded so good in a module!  Onto the build … 


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