The Klee Sequencer.
- Linear Pattern Sequences
- +/- 15vVDC operation
- Three channel, programmable CV, Gate, trigger Outputs
- External, CV or random sample clock.
A few years ago, I heard about this amazing analog sequencer Scott Stites had designed. Scott was a regular in the online synth forums, and had offered sets of printed circuit boards for sale. I missed out on those early releases, but was fortunate enough to obtain a set though Synthcube. In fact you can buy complete kits, or this thing fully assembled in two different formats from Synthcube. So, my set of PCBs lay for about a year and then in the winter of 2018, I decided to build this fantastic machine.
This will possibly be one of the hardest sequencers anyone will build, it is also hard wrap your head around how it works. A ‘regular’ linear clock driven sequencer is fairly straight forward. Even my Quadratic Sequence Machine, is somewhat easy to understand and program as an analog computer of sorts. But this….. this is quite different. Unlike the step sequencer, which progresses one step at a time, this sequencer starts with a pattern and can change the pattern each step, depending on how additional sliders are set. Here is a really great explanation on Gregory Taylor’s website, Cycling 74 I am not going to paraphrase Greg or Scott’s explanations, they explain it much clearer. I will focus instead, on my experiences building the Klee, and showing how cool this thing really is.
The Build Concept
For this sequencer, I wanted the completed Klee to sit in my studio rack. So, I started deciding on a 19″ standard rack panel design. For those that don’t know, standard rack mounted equipment is 19″ wide, but various sizes in height. Each size occupies a ‘Rack Unit” or ‘U’. The sizing starts at 1U (1-3/4″) and progresses up for each 1-3/4″ in size. So 1U, 2U, 3U, 4U…..etc. I decided I could fit all of the controls for the Klee into a 3U panel size or 5-1/4″ high. I searched through the various synth portals, looking at the designs of others, and incorporated many of their designs into mine. I then laid out the panel in an application called “Front Panel Design” which is proprietary software supplied for free, by “Front Panel Express“. Of course….. Front Panel Express is the only people who can build your panel using the software output file. And, trust me… it is not cheap!
Choosing your own components means you can really use your brain in free-flow mode to come up with a design. Since I chose the switches, the potentiometers, knobs, LEDs, etc, meant I could close how they fit. I decided to use linear sliders instead of rotational potentiometers. Checking out the builds from others definitely showed me that it would be easier to read. If you buy the Euro-rack version, all the panel components are mounted onto a circuit board. This has two benefits, it cuts down on the point to point wiring, and it helps improve reliability when moving this around. But My PCB were not intended for Euro-rack, so I would have to solder everything to wire. To make it easier for the sliders though, I made small PCBs that hold each slider, and enable easier wiring connections.
Then basically, you start stuffing the components on the panel. Here is where you hope your design was triple checked to ensure everything fit properly
For this build, there are two PCBs, one analog and one digital. Here is the completed analog circuit built. Now, to start the arduous process of building small wiring harnesses with a connector at one end, and tined leads on the other that will connect to the components on the front panel.
The build guide found on the Muffwiggler forum really help you with this project. There are also some optional voices you need to determine first, before you lay your panel out or even solder components. There is a detailed test section which will assist it helping you make sure your Klee is also working effectively.
Here is my final Klee Sequencer being send to a pair of CV to MIDI boxes and out to a Deckard’s Dream Synthesizer and an Alesys SR18 drum module.