Synthrotek DS-M

I built the Synthrotek Dirt and Echo kits a few months ago. I love em both. The echo is used in almost ever patch I make. 

I got the DS-M kit in and quickly built it up. Had some trouble tuning it at first. I used my Minibrute set to arpeggiator hold in 4 octaves with middle C. I had it looping while tuning until the tuning was near perfect. Tracks really well now. 

The DS-M obviously makes great percussion sounds, but it sounds really cool as a VCO too.

The Cheater's way of Syncing When Circuit Bending

There come times in circuit bending when I just don't feel like putzing around and finding the clock's source for proper syncing. Sometimes, I feel like it just doesn't exist outside the silicone of those random NEC chips. 

Let's take my Casio MT400V which mysteriously sat unopened for 5+ years ($1 garage sale find). Popped it open Sunday, and spent the better part of the day tracing around and trying to find the sync signal. 

I've done this in the past and it always worked and I should just do it from here on out: LED. Thats right, tie into the LED that is showing you the tempo! Toss in a simple transistor circuit there and bam! Clocked gate for your Eurorack.  I used the PEG to multiply it up and the MT-400V was synced up with my modules.

Let me know if you have any questions.

Also, check out PartSim. It is a super easy to use online SPICE simulator. Should help you dial in your transistor circuit for the gate. 
PartSim - Online Circuit Simulator with SPICE | PartSim

The Internet Of Synths

For years, I've wanted to be able to make music with the help of real world data like weather. Using weather, bus patterns, stock data, oceanographic data, ect., you'd be able to make real "live" music that will never repeat again and reflects something happening in the world. I've tried to implement this using software like Max/MSP, Pure Data, and others, but I was never able to properly interface with the various APIs. While working at Quirky, I've learned a lot about how the internet works and that it really isn't such a scary beast; it is actually quite simple. 

Since my modular synth has been the focus of my attention over the past few months, I decided to build a piece of hardware that will interface with the internet to pull real time data from APIs. 
The hardware of choice was the Electric Imp. Using the Imp, you can connect to your WiFi network and program it to both pull and send data to the internet. 

It took me about an hour to get the Imp set up with an API from a weather website in JSON format. The website was free, so I was only able to pull in temperature data and it refreshed every few minutes; it was by no means real time. I set up the Imp to output analog voltages via one of it's two DAC pins and eagerly plugged it into my Euorack's Pittsburg Modular Waveforms. Not sure what I was expecting; nothing exciting happened. 

I then stayed up till 5AM learning Javascript and I came up with this:

What you see there is the Imp plugged into the synth. USB is only plugged into the Imp to power it, not for data. The computer has a simple slider webpage that sends the slider values to Firebase, a great free data syncing website with an easy API. The Imp then reads the values from Firebase in the Agent code, sends it to the device code, then outputs the float out of the DAC. 
Nothing too exciting, but it is still a synth being controlled over WiFi from a website.

The next day, I got set up with the iOS developer program at work, so when I got home, I eagerly made a quick iPhone app to control the synth. 
I broke out the rest of the pins on the Imp and mounted them to my Quirky Business card since I didn't have any project boxes handy. 

With all the Electric Imp Pins broken out, I had 2 pins set up as analog outs, and 4 digital pins that can output PWM. I really wish the Imp had more than 6 pins. There are other Imp modules in existence, but this is the only one with DACs at the moment. 

I also have to mention that the Imp only puts out a maximum of 3.3V, so amplification is needed to make this work properly with my Eurorack. I plan to do this in the coming week with a TL072 for the analog and TL04s for the digital. This way, I can swing the signals from 0-10 volts and properly trigger the Eurorack and get a longer range of CV control.

I made an iPhone app with 2 pages. The first has 2 sliders to change the analog outputs from 0-1.

The second page controls the digital pins. Each pin has an option to set it high (1), low (0), or turn on the PWM to use it as a clock/square wave with 50% duty cycle.  This was especially fun with the Make Noise Pressure Points where I can control the clock speed, direction, and run on/off with the iPhone. 

In the coming week, I hope to settle the analog amplification of the Imp's pins.

I also hope to find free APIs I can use to start triggering the Eurorack with real time data. 

I will hopefully have an update in the coming weeks along with source code. 

More Modular Silliness

The eurorack is coming together beautifully. Just waiting on an Expert Sleepers Disting and I'll be done for a while. 

Made this fun little thing tonnight:

The Beginnings of the Eurorack

I decided to take the plunge and dive into Modular with a Eurorack setup. I figure that all I do is modify my equipment for control signals and chain them up, why not add in some equipment that is made to do that.
The case is a 9U rack case with 2 Tip Top Happy Ending rack ears with 2X uZeus power supplies.
The top 3U is just a blank panel. I used velcro secure the Volca Beats and Bass. The sync in/out on the Volcas plays really well with the modular's gating. The Beats has very usable White and Pink noise thanks to my earlier mods. The Bass (not pictured) is currently taken apart for investigation. I am determined to get the CV and gate outs for each of the 3 voices so I can make the Volca Bass a seriously badass sequencer for my modular. I've found a few points and am investing additional circuitry to make it happen. I've found the gate points, but the voltage needs to be bumped up from the 3.3V that the Volcas run off. Details to come.

Here are my current modules:
Pittsburgh Modular Synthesizer Box
Pittsburgh Modular Waveforms
Pittsburgh Modular Passive Multiplier
Make Noise Brains
Make Noise Pressure Points
TipTop Audio MixZ
Pittsburgh Modular Outs
Synthrotek Dirt Filter
Malekko VCA
4ms Rotating Clock Divider
4ms RCD Breakout
4ms Pingable Envelope Generator
Synthrotek Echo

I've already had a lot of chaotic fun with these guys, I have a DSI Curtis Filter on order and a Mutable Instruments Braids on the way.

Eventually, I want a Make Noise Wogglebug and René. We'll see about that.

I really like getting this guys going with the Arturia Minibrute and Korg MS-20 Mini. There is a lot of fun to be had with all 3. I use my Minibrute as a MIDI>CV converter too, along with being a great arpeggiator.

There is much more to come! Including new Eurorack module designs.

Simple Sequencer Schematic. Used in MS-20 mini mods.

I've had a lot of requests for the schematic of the sequencer I used in my MS-20 mini mods. I've been very busy, but I finally drew them up all nice and perdy. 
The circuit is a super simple one based off the 4017 decade counter IC. The clock input can be from anything with a pulse like the MS-20's square LFO, Volcas, drum machines, ect. I didn't hook up the reset due to lack of space on the MS-20 mini's chassis. This circuit gives you a gate and CV output for fun step sequencing. 
The 4017 is powered by the 9 volts inside the MS-20. 
Here is a Larger Image.
I admit that this circuit is very rudimentary and additions can be made to add more features. You can add jacks to each step so you can change the length of the sequence using the reset line. So many possibilities. 
I added switches on mine so you can choose to engage or disengage the gate for individual steps for fun rhythms. 
I also want to add a portamento switch that engages a portamento between steps. I'll document this when it's done.
If you want to get really fancy, you can throw a microcontroller into the MS-20 and read off the MIDI from the MIDI port and get clock signals to MIDI sync you sequencer. Leave a comment with any fun additions you do. 

In other news, I have resigned from Ernie Ball / Music Man and accepted a job in San Francisco with Quirky. I want to get involved in the synth scene here. I am pretty sure it has to be bigger than SLO's. Let me know if you life in SF and want to make music or need repairs or anything. 

Moog Circuit Bending Challenge 2014 Entry

The competition rules stated that the bend had to cost less than $70 dollars, run off 9V batteries, and be repeatable. Source code and schematics will be available via GitHub in the coming weeks (once I clean it all up)

I bent a Yamaha DD6 to mash up drum samples using an iPad.

I used an Atmel XmegaA3BU Xplain board as the brain along with an Intersil crosspoint switching matrix IC. The Xmega communicates with an iPad via USB by functioning as a class compliant USB MIDI device. There are 3 buttons on the board; an up, down, and enter button. When the device first powers up, it is in the "HOME" screen. The "HOME" screen also acts as a way of clearing a preset so the DD6 can go back to stock when using the device, by pressing enter when "HOME". Any of the 10 presets can be recalled by scrolling to them and pressing enter. The last position in the menu is a "RANDOM" setting which creates a random preset. 

The app on the iPad allows you to make connections on an 8X16 grid, which creates 3.4e38(!!!) possibilities. Using the iPad, you can save your preset to one of the 10 available preset locations on the device. With the iPad, you can also clear all the connections or make them all. 

I also added a sync out from the DD6. This sync allows me to clock an external sequencer or even a Korg Volca. 

Here are some of the videos:

This video is actually the last video, but it includes a discussion of the overall project and sound demos at the end. 

Going over the hardware.

The iPad app and it's code

XMega firmware code