Tuesday, July 17, 2018

Introducing My 101-VCF Euroack Adaptation Roland SH-101 Filter

Today I am proud to show you my 101-VCF - my adaptation of the Roland SH-101 lowpass resonant filter in a slim 8HP Eurorack module. A filter described as somewhere between a Juno and a 303. Every effort has been taken to preseve the original analog circuit as much as possible. Be warned - some harsh resonance squealing ahead! Recorded direct via Mackie mixer to Tascam DR-05, no effects or post-processing.

Oscillators - Pittsburgh Synth Box Square, PWM, Sub Envelope Contours - 2xADSR dual envelope, Bastl Skis Sequencing - Arturia Beatstep Pro Pitch CV + gate

More details at https://www.modulargrid.net/e/other-unknown-101-vcf

Monday, June 18, 2018

Oberheim Matrix-12 Synthesizer Percussion Demo

OMG that Snare sounds familiar. No drum machines or samplers were used in this demo. No, today you're getting a full dose of Oberheim Matrix-12 percussion sounds. Watch as I corral a group of freshly programmed percussion sounds together using MIDI assignments in multi-mode. The Beatstep Pro is in full trigger control. Muting tracks is done on the M12 channel volume page. Recorded direct to Tascam DR-05 via Mackie mixer. No effects mucking about whatsoever. I should be making the patches available sometime soon. Thanks for watching!

Saturday, June 9, 2018


Today a follow-up demo of my Uniox Minikorg w/ a Pitch CV + Gate mod controlled by the Arturia Beatstep, this time sans the annoying percussion. This synth is one big continuous sweet spot! Some delay by Timefactor, a touch of Big Sky reverb, recorded directly via Mackie mixer to a Tascam DR-05. Press play, kick back and let it ride.

Monday, May 21, 2018

2xADSR Dual Envelope DIY Project

And here it is...a dual 4-Stage envelope generator 8HP Eurorack. 2xADSR is a dual envelope module in 8HP Eurorack format based on the Arturia Minibrute. The schematics are openly published on the internet, so it would seem reasonable to have adapted a fun DIY panel/pcb project for educational purposes under fair use. Each envelope is an independent Attack-Decay-Sustain-Release linear contour. Each envelope takes a gate input, puts out a positive-voltage contour and a buffered negative-voltage (DC inverted) contour.

This is a DIY project, just a pcb/panel only, with surface-mount soldering required. You supply the parts components (not included), but it uses all very affordable and easy-to-find parts. I would not recommend this as your very first SMT build, maybe your 2nd or 3rd SMT build though. The BOM and Schematics for this project can be found on muffwiggler
PCB/panel are available in my Reverb Store

Friday, May 11, 2018

Testing Univox Minikorg CV+Gate Analog Synthesizer Mod

Testing out a Pitch CV + Gate mod for the Univox Minikorg, AKA Korg 700/700S. The arpeggio gets faster and ends up sounding inspired by Pink Floyd On The Run. The circuit one the breadboard is from E-Labs, Japan as shared by Cykong.com. I added a buffer on the gate since the Beatstep Pro trigger did not push enough current to make it happen. Strangely, the gate does work w/ the original MS-20. Beatstep Pro can do Hz/Volt, this setting can be made in the Arturia Midi Control Center software. Recorded direct to Tascam DR-05, no additional processing. Here's the lowdown:
Synth - Minikorg
Percussion - Basilimus Iteritas Alter
Percussion Trigger - Varigate4
Delay - Timefactor
Reverb - Big Sky, Hall setting

Friday, April 27, 2018

Spring Tank Reverb Eurorack Prototype Module

Today I am showing my prototype Spring Tank Reverb module. It's a driver for old school spring tanks like those found in vintage mixers and guitar amplifiers. The driver module has controls for Drive, Tone brightness and darkness, wet/dry mix, and an input for sending CVs to control the wet/dry mix. I'm using an envelope for CV, Beatstep Pro for trigger sequencing, and beats are coming from the Future Retro Transient. I also run the signal through my dual channel compressor, using a trick where both channels are cascaded for additional compression. I also briefly punch in some delay from Timefactor. Audio was recorded direct to Tascam through a Mackie mixer. EDIT: I noticed some users are connecting this to things that are not eurorack systems. To assist you w/ your efforts here are the active pins on the power input.

Sunday, April 15, 2018

Spring Tank Reverb Breadboard Eurorack Demo

Try not to let your heads explode when this sickness fondles your eardrums. Got my hands on an O.C. Electronics Spring Tank Reverb. On the breadboard I've built a driver circuit with voltage control of the wet/dry crossfader. Who does that???!!....

I do that. And today's demo shows you why. The Future Retro Transient+ is going through the spring tank. The mix is set mostly dry, but I'm using a short envelope to send a burst of reverb wet mix when the snare hits. Using the Beatstep Pro for that. That's what I'm talking about. That. Is what it's all about.

How did I do this? I've frankenstein'd a couple of circuits/ideas together to make this happen. At its core is a Tombolas DIY Spring Reverb Circuit w/ EQ and Drive Control to accommodate a wide variety of tanks. It worked very well, but I was not yet satisfied. For the Voltage Control, I've slapped away the final amp mix stage and replaced it w/ the VC Crossfader circuit by Thomas Henry. I dumped his VCA control, that's another project for another day, and to made some minor changes so it would play nice w/ the Tombolas circuit.

Tuesday, April 10, 2018

My DC571 Dual Compressor for Eurorack is Now Available

My DC571 Dual Compressor for Eurorack is now available in my Reverb Store. To operate the DC571:
1) plug in the audio input and output, making sure some sounds are present
2) set the switch up (compress) to activate the effect
3) turn the input knob until you hear clicks/pops (clipping) and then back it down a little
4) set the switch down (bypass) to compare the volume of the original signal
5) set the switch back up and turn the output make-up gain knob until the volume is the same as when you started. You may need to repeat steps 4 & 5, and it’s definitely ok to increase the output a little bit more if so desired! For even more compression, the channels can be cascaded in series. Do this by patching the output of channel 1 into the input of channel 2.

Sunday, April 8, 2018

RM&S Ring Mod + Sub-Octave Generator now available

My Ring Modulation + Sub-Octave Generator module is now available at Reverb dot com!

RM&S is a 4HP Ring Modulator and Sub-Octave generator. The Ring Modulator is an active, CMOS-based circuit adapted from the ARP Odyssey. Ring Mod is usually generated from inserting square wave VCOs to Input 1 & 2. But that shouldn't stop you from sending sawtooth, wavetables and noise sources through this.

The Sub-Octave Generator circuit is derived from the Roland SH-101 and provides -1 and -2 octaves from a square wave plugged into Input 1. Many VCOs put out varying degrees of signal amplitude, a trim pot is provided to adjust input impedance of VCOs for the Sub-Octave Generator circuit.

Output jacks include: Ring Mod, summed Ring Mod + Sub-1, Sub-1, and Sub-2. The RM&S is hand-crafted in the USA.

Measured Current Draw: 2mA on -12V, 5mA on +12V, 5V not used

Monday, April 2, 2018

Three Machines = MS-20 + Juno-1 + Eurorack Synthesizers

Feelin' a good 100-bpm chill vibe today. Three Machines are: Korg MS-20, Roland Alpha Juno-1, and the Eurorack system. Future Retro Transient+ is swinging a nice CR-78 groove thanks to mapping some CVs from the Beatstep Pro, running through the Delta VCF to take the edge off the highs. The CEM3340 VCO doing the arpeggio thing using quantization from Ornament & Crime, running through the Tonus VCF. Euclidian triggers from Temps Utile. Bass from the Synthesizer Box. Playing a delightfully mindless riff on the MS-20. Some Timefactor Delay, some Big Sky Reverb. Recorded in one shot, some post-work done in Cubase.