Jürgen Haible – Tau Pipe Flanger

Jürgen Haible from Germany redesigned the Tau Pipe flanger and documented the test and build in great detail at his site http://www.jhaible.de.

His site has more information than you could ask for when it comes to synth and audio effects DIY.  He includes schematics, block diagrams, design and test notes, high resolution pictures, mp3s, external links to resources, formula calculators, spreadsheets, etc.   He does this for over 25 projects.  It’s truly impressive.  Take a look at the images of his Tau Flanger/Phaser redesign…

Tau Flanger/Phaser Redesign by Jurgen Haible

Tau flanger/phaser redesign by Jurgen Haible

Ryan BoCook – Synth DIY and A Victoreen Geiger Counter

I happened across Ryan’s excellent DIY synth and immediately recognized the housing he used for it.  It’s a Victoreen Radiological Survey meter.  You can find these in abundance on eBay for pretty cheap (which is exactly what I did).  Hats off to Ryan on this really cool modification.  You can find images and more about Ryan on his site Pickleinn.com

Ryan Bocook - Victoreen Synth

Audio Test & Development Box

I frequently work on projects in the living room in front of the TV while sitting on the couch soldering away hunched over a disarray of wires, parts, wires, speakers, cords, breadboards, and tools. Whenever I want to work from the couch I have to go into the studio and make 15 trips up and down the stairs, cables, toolbox, parts boxes, soldering iron, etc. It’s always a major hassle. Then, when I’ve finally completed mocking something up on the breadboard and I want to test it I need speakers, headphones, a sound source and I have to connect it all with alligator clips. It’s really inefficient and makes me less apt to start a project because all I can think about is the huge mess it’s going to make.

So I decided to put everything I need into one self contained box; an audio test and development box. Below is a description of the parts and procedure I used to put it together. If you’re in a similar situation hopefully this will give you some inspiration to come up with a solution that works for you.

If you want to see all the project photos in high resolution you can find them on Flickr here: Audio Test Box Images

Initially I needed to build a box. I looked through all my scrap wood and it was all ¾” plywood which would be way to heavy. The smaller pieces were odd shaped and unusable. I looked at everything from cookie tins to shoeboxes and didn’t like anything I was coming up with. I checked Wal-Mart for something I could get cheap and hack into what I needed but I didn’t find anything there. Then I went to Hobby Lobby because I remembered they had some project boxes for putting flower displays in. After looking through the whole store though I found the perfect box. It’s a miniature “child’s desk” with a top that lifts up. It was exactly what I was looking for, I just didn’t know it. Best of all, it was only $15. You can find them here: Wooden Child’s Lap Desk

What I wanted was a box which had a variable DC power supply, an AC jack, an amplifier, speakers, an audio source, an AC outlet for the soldering iron, a place to put some tools or parts, a quick way to hook up audio ins/outs and DC voltage, and room for multiple breadboards.

Most of it I was able to find around the house. Here are the guts from a pair of old busted up (but functional) computer speakers. These had been lying around for years. But even if I didn’t have them I see them all the time at Goodwill for a couple of bucks. It was a bit of a pain to crack these open. Most of them are manufactured so you can’t service them so you have to break the seal on the plastic to get to the guts. I just used a screwdriver and pried the crap out of it until it snapped. Dirty but easy.

The DC power supply I used was one I had purchased a couple of years ago for a project. It’s a Meanwell Switching Power Supply that I picked up at Fry’s. Fry’s is one of the last few national stores that still carry electronic components. It’s convenient if you need something right away… just hop in the car and get what you need… but be prepared to pay a premium. Anyway, this is the power supply:   Meanwell Switching DC power Supply I’ve used this power supply dozens of times and it’s great. AC in, DC V+ and V- out with a neutral earth ground. The voltage is adjustable from 10 to 15V DC which covers just about anything I’ll ever do.

Skipping ahead, I started drilling and cutting openings for the parts. Depending on what you’re using for parts and a box you might have to do something different but this worked well for what I was doing. The two speakers in the bac and the AC cord jack on the front right corner so I could comfortably plug it in. I used two tools to cut the holes. The circles were cut with a Dremel tool and the rectangular hole I used a chisel. The wood on this Hobby Lobby box was really soft so chiseling out a hole only took about 10 minutes. One word on chisels… never use them for anything other than wood, store them safely, and keep them oiled. Nothing worse than a fucked up chisel.

The speakers fit perfectly in the back corners of the box. I really couldn’t have built something better than what I bought at Hobby Lobby. And like I said, the wood was really soft so I was able to screw in the speakers directly into the wood using the screws used in the original plastic enclosure. This was much easier than sifting through bins of spare parts finding something to fit. Screwing in the AC jack was equally simple.

Next I installed the amplifier section of the computer speakers. I wanted to use the original DC power supply that came with the speakers so I wasn’t running it off of the supply I’d be using for a project. I simply screwed in the transformer directly into the wood. Now, this probably isn’t the safest way to go about this. The wires are exposed, and there’s no heat sink so do this at your own risk. Next I needed to attach the amplifier to the box. I didn’t have any standoffs that were the right size and the mounting holes were in awkward positions. I decided to make my own brackets. I frequently make brackets for projects using ½” brass strips. You can find these at pretty much any art supply store or train/model hobby store. They’re cheap, really strong, easy to bend, and easy to cut with a Dremel. A couple cuts, bends, and holes drilled and I was set up. I used mounting screws and nuts to adjust the height and stabilize the front of the circuit board

So when soldering it’s important to keep a wet sponge near by to occasionally wipe the tip. I made my own little portable holder that I’ve used for years now. I love Pillsbury’s Flaky Supreme cinnamon buns. When you’re done baking them you slather on that super sugary frosting and they’re delicious. I keep the plastic containers that the frosting comes in and wash it out, cut two plain old sponges in circles and plop them in the plastic container. Add water. It’s just the right size and stays wet for a day or so. Only problem is that it slips and slides all over the place which can be a hassle.

So, to keep the sponge from sliding all over the place and keep it at arms length I chiseled out a circular depression in the top of the box which the plastic container can rest in. Again, the wood is soft on these boxes so it didn’t take long at all. Just took a little patience so that I didn’t slip and chisel out a huge piece of wood.

Next I wanted a built in outlet for my soldering iron so I didn’t need to keep an extra power strip handy just to use one outlet. I went to home depot and bought a wall jack with only one outlet. In this instance I bought a safety outlet. I figured since I’m mounting the outlet directly to wood, with no switch, or fuse the least I could do is get a safety outlet. I’d suggest putting in a power switch and fuse if you try this. Chiseling out this hole took a bit longer and the wood needed to be notched out so the outlet would sit correctly. Also, because of limited space on the side panel I had to trim off the ends of the mounting brackets (not shown in this picture). The Dremel saves the day again.

Skipping ahead, here’s the AC wired up. I stripped out the heavy gauge wire from an old busted power strip and trimmed it to size. I added some heat shrink tube for color coding. The wires on the end of the AC input jack needed to be soldered but on the other ends I crimped on some spade tongues so I could connect/disconnect the wires quickly and easily if needed. I did this for all the AC lines. The wiring is pretty simple. White and black or the power inputs and the center is ground. I go from the input to the outlet to the power supply. Not visible in this picture is the AC power going to the amplifier in a similar fashion.

I had to drill a number of holes on the lid of the box so I could mount binding posts, switches, and jacks. Because the wood was ½” thick I needed a small hole on one side and a large hole on the other to fit the body of the component. Drilling the small hole is easy. Just choose the size that matches the width of the threaded mount on the component. To make a larger hole that sinks in to the correct depth I use an old trick. Measure the depth you need up the drill bit from the tip and then wrap a bunch of masking tape around the drill. Now drill your larger hole over the smaller hole and only go as deep as the tape. I tend to add a lot of tape so in case I push to hard the tape actually stops the drill so I don’t go all the way through the wood and ruin the hole.

Here I mounted three binding posts across the top of the box for DC power. I simply drill holes and screwed the plastic posts into the holes. The wood is soft so they took really well. I did have to tweak the size a bit with a round wood file but that was minimal. Because you can’t get in under the top of the box it’s necessary to solder the connection wire to the bottom of the binding post before you screw it in. I made sure to use heat shrink given the proximity to the DC & AC power wires.

Here are all the binding posts jacks, and switches installed followed by an image of the underside of the lid. All jacks were wrapped in heat shrink tubing. I tidied up the wire using staples from a staple gun. Instead of using the staple gun though I gently pushed the staples in with needle nose pliers so as not to knick the wires. After I had put this all together and tested it I was having a hell of a time getting the audio out to work right. The wiring wasn’t at all complicated so I had no idea what was wrong. I should have known though… one of my switches I bought at Radio Shack. So besides being completely ripped off by having to pay $3.99 for a $0.20 switch, I also got totally hosed because their parts are worthless shit.

These last two are the finished box (for now). You can clearly see I can fit around four or five breadboards vertically on the top of the lid if need be and all my ins and outs are in easy reach. The lid opens up and provides enough extra space to keep the AC power cable, a soldering iron, the sponges, some solder, needle nose, a pencil, or whatever. On the second picture if you look inside you’ll see a little RCA .mp3 player. I bought this at Wal-Mart for 30 bucks. It’s 2GB mp3 player/flash drive that runs on 1AAA battery. What I’ve done is load up 25 clips of various types of instruments or sounds. Guitars, vocals, drums, bass, synths, full songs, etc. This way when I’m testing an audio circuit I’m working on I can listen to how instrumentation actually sounds running through it. And when I’m done I can grab it and go. I used to have an iPod and lost it… which I was OK with because iTunes irritated the crap out of me. This thing was super cheap, has plenty of storage for what I need, and all you need to do to add .mp3s is drag and drop.

And last but not least, here’s a poorly drawn diagram of the entire operation. I’ve set it up so that either an internal or external audio source can feed the development circuit via the internal .mp3 player or an auxiliary stereo ¼” jack. Just connect the input binding posts to the circuit you’re working on (left, right, gnd). If your not working on a stereo set up I’ve added a mono/stereo switch which merges left and right and sends it to the ‘left’ binding post. Second you can easily hear the impact your circuit has on audio I’ve added a bypass switch so you can toggle between your circuit and direct audio out. Third, when the audio exits your development circuit it feeds into the binding posts on the right which subsequently feed the internal amplifier and speakers. Should you prefer to send the signal out to an external amp (or whatever) you can do so via a second stereo ¼” output jack. If the signal from your development circuit is mono, there is a stereo mono switch that sends the mono signal (connected at the L binding post) and feeds it to both the L & R inputs of the internal amplifier. I’ve tried to draw it out so it makes more sense than I’ve written it here. Of course, if you have questions just leave a comment or email me.

Click for Hi Res

PAIA Theremax Theremin

Because of a lack of new content I’ve resorted to posting old projects. This is one of the first builds I completed somewhere around 1995, a PAIA Theremax Theremin. PAIA has been around since 1959 and has been making DIY kits for musicians for decades. In addition to several analog modular synthesizers, Reverbs, EQs, a vocoder they also have their twist on the Theremin, the Theremax.

From PAIA’s website:

…In addition to the traditional mellow sine-like tone, Theremax’s Timbre control can mix in a harmonic rich square wave to produce a signal that’s ideal for use with external filters and processors. And to control outboard units, there are Pitch and Volume Control Voltage outputs.

But the features that really set Tmax apart as a gestural controller are it’s Velocity Control Voltage (proportional to how fast you increase the Volume) and Gate/Trigger outputs. A convenient foot switch input allows muting the internal tone source without disabling the CVs…

Panel controls:

  • Pitch & Volume Trim – these control provide a vernier null of the reference and variable heterodyneing oscillators in the Pitch and Volume control circuitry.
  • Pitch CV – controls the range of control voltage produced in response to hand proximity to the vertical pitch antenna on the right side of the instrument. Clockwise rotation increases range up to a maximum of 6 Volts. This control does not effect the sensitivity of the internal pitch circuitry.
  • Timbre – controls the brightness of the internal tone generator. At full counter-clockwise rotation the output is pure sine wave. At full clockwise rotation the output is a square wave. Intermediate settings produce a mix of the two.
  • Velocity – controls sensitivity to rate of change of volume level. At min, there will be no velocity response no matter how fast volume is changed. Rotation toward max produces increasing response. At max, the Velocity Control Voltage output will produce a 4 Volt change in response to the quickest possible hand gestures. This CV is a transient with a time constant on the order of a second. Internally, this CV biases the VCA for asymmetrical distortion, with no distortion at the min setting.(asymmetrical, transient distortions are responsible for some of the perceived “punch” in natural instrument) This control also sets Gate/Trigger sensitivity, at max sensitivity the gate will respond to very slow movements of the Volume hand.
  • Volume – adjusts the sensitivity of both the internal VCA and external Volume CV output to hand movement relative to the Volume antenna. Output level is adjusted here, but more importantly this control is capable of driving the VCA into symmetrical distortion. (symmetrical distortions are responsible for much of the “loudness” of instrument when played fortissimo)


  • Mute – a foot switch, or S-trigger to this jack mutes the internal pitch producing circuitry. CVs are not effected.
  • Pitch CV – Control Voltage proportional to hand proximity to the Pitch antenna as ranged by Pitch CV control.
  • Volume CV – Control Voltage proportional to hand proximity to the Volume antenna as ranged by Volume CV control.
  • Velo. CV – Control Voltage proportional to how fast a hand is moved in proximity to the Volume antenna as ranged by Pitch CV control.
  • Gate/Trigger – This TRS jack provides a 5 V. gate signal at the “tip” when Velocity exceeds a threshold. The “ring” connection is an S-Trigger compatible closure to ground. The LED lights to indicate a triggered condition. (note that the gate responds to change in volume, i.e. how quickly the volume control hand is moved, not the static location of the hand)
  • Audio Out – Output level is adjustable with the volume control but is nominally -10 dB.

I didn’t have the cash for the nice wooden desktop enclosure so I built my own out of spare wood and used metal shish kabob skewers for the antennae (not pictured). The Theremin still works well to this day although I’ve always had a little bit of a problem with the volume control. The 9v DC power supply is hard wired into the unit which was a poor decision on my part. An easy fix if I ever get to it. I’ve used the gate output to trigger an old Alesis D4 with good effect. The voltage control outputs are perfect for controlling various parameters of an analog modular synth.

If you’re comfortable around a soldering iron this is a great kit, an easy build, and for just the electronic kit it’s only $115. Money well spent considering what you’re getting.

16 Step Sequncer & Synth: An Update

This is a follow up to my original post on the 16 step sequencer/synth that I posted several months ago. It’s taken some time to get moving on this but I finally ordered up 32 pots to test my design and make sure everything was working. The overall concept is to have a 16 step sequencer where each step allows you the flexibility to adjust the VCO, LFO, envelope, noise generator, and filter on each step. The sequencer will allow you to switch, for example, the VCO from individual control on each step to a global setting. This would hold true for all parameters. The sequencer will step forwards, backwards, and allow you to select how many steps to make (1-16). Each step will have an optional output that bypasses the main output when used. Finally, the sequencer section will have a speed or rate control. I’m still debating if I want to figure out how to make this sync to a midi clock or display a BPM reading. When it’s all finished it will have over 80 dials, 50 switches, and plenty of flashing LEDs for those late evening explorations. Video to follow soon…

Also, I’m getting to the point now where I need to consider what type of enclosure all this will go into. I’m looking for carpenters, machinists, and artists to talk about unique ideas and options. If you interested shoot me an email.

Synth - Sequencer

Here we have 32 pots temporarily wired up on a piece of cardboard. This was the cheapest and most reasonable way to wire up the amount of pots for just a test circuit. I do this frequently when I need a quick mock up for controls. These are 1M linear taper pots and they’re all wired with a common ground and then each one is individually wired to a multiplexer input. I should be able to just take these out of the cardboard and drop them into the finished control panel when it’s completed.

Synth - Sequencer

This is full shot of the prototype prior to some sequencing enhancements. You can clearly see the leads from the pots coming into the 4067 multiplexer. It’s only necessary to run one set of 16 leads to the multiplexer, each additional row of pots can be wired to the previous with only the addition of one unique lead to the control input of the sn76477. A 555 timer is wired as an astable multivibrator for the clock and is sufficiently stable for my purposes. Although difficult to see in the image the sn76477 has a regulated 5V DC output to drive your logic ICs regardless of what your power supply voltage is. The group of black leads with green shrink wrap brings over the 4 bit binary count to the second multiplexer. In this image the binary counter is a 4520B dual binary counter. The original plan was to utilize both counters and a comparator to set the sequence length from 1 to 16 steps. The three switches at the top of the rightmost breadboard are for selecting the mix channels of the sn76477. through a combination of these switches you can include a VCO, LFO, decay, noise generator, and filter as well as bypass the sound completely. Like the pots these will be added for every step in the sequence for tailored sounds on every step of the sequence.

Synth - Sequencer

In this photo you can see some changes have been made. I swapped out the 4520B dual binary counter for two SN74LS193N pre-settable up/down 4 bit binary counters. The output of one counter is wired to the multiplexers and controls the sequence and then flows into the 4063B 4 bit comparator. The second counter is manually stepped manually with a push button switch and also feeds the comparator. Count A > count B a high signal is sent to the master reset of the sequencer counter and the sequence starts over at the beginning (0). The two switches off the side of the leftmost breadboard are required to allow for running the sequence in reverse. They serve two functions 1) to switch both counters from up to down counting and 2) to send a preset to the sequence counter on reset. Normally the counters reset to 0, but when going in reverse you want it to reset to 15 otherwise your sequence gets stuck on 0 indefinitely (due to the comparator condition always being met). Make sense?

Synth - Sequencer

This is just a close up of the hectic wiring going on. I only have yellow and white wire so it makes for a confusing time tracking down and correcting problems. In the left-middle you can see the 555 timer obscured by a couple yellow wires. Currently the frequency of the clock is variable with a duty cycle of 50%. One of the next steps is to include another timer so I can retain adjustable frequency and adjust the duty cycle to something much higher like 90%. This won’t impact the sound but it will make the LEDs flow from step to step smoothly… a totally superficial enhancement. On the lower right is a 3 input multiplexer to handle sending the reset number to the sequencer clock when running in count down mode. Another next step is to add an analog switch to replace my two toggles to switch from count up to count down mode.

Jakob Lysgaard and the Dub Siren


Jacob Lysgaard recently contacted me while he was working on building the Dub Siren I posted here and on Flickr. His documentation and description of the required parts, where he bought them, his findings, troubles, and experience while building it is far more informative than my images and flagrant plug for Bastard Jazz.

I’m happy to see someone has not only successfully built the dub siren but is finding use for it in their performance. All the best to Jacob.  You can find the post on his blog here:  DYI Dub Siren – the complete rubdown.

RLM – Wildlife


Somewhere around 2000, shortly after I broke the lease on the worst apartment ever at 148 Degraw Street in Brooklyn I moved in with my best childhood friend Jamie and his roommate Dan on 7th Ave.  A railroad apartment, that was far too small for two people, let alone three, was my home for a couple months before I finally moved out into the amazing but nearly deadly ‘4th & Garfield’.

During that time I was working on a number of projects, drinking more beer than was healthy, and had set up shop in the dining room of their apartment.  Jamie and his friend Steve were both DJing down-tempo music at the time and thought a collaboration on a mix blending exceptional vinyl selections with the advancements in software based synthesis and tracking was overdue.  Tracks were selected, reselected, mixed, remixed and stitched into a seamless blend of great down-tempo of the time.

RLM was formed, and the Wildlife Mix was forged.  Roberts, Langolf, and Marchese: an original formula for a name without doubt.  This was a brief collaboration that resulted in the release of one full length mix on CD for circulation to whoever would have it.  After all this time I still have a number of CDs in my studio that are collecting dust.  Want one?  Email me and it’s yours.  Or, you can download the .mp3 below.  I recently uncovered the track listing…. These are surely out of order but credit is necessary for the original artists.

  • At Jazz
  • Certain Peace
  • Drifting
  • Eclipse
  • Eric Kupper
  • Ginger & Fred – Voom Voom
  • Lagente Urbana
  • London Elektricity
  • Pepper Digs
  • Chattanooga Nugget
  • Yoruba
  • Que Domingo
  • Restless Soul
  • Root Down
  • Slow Supreme
  • T-Kolai – exodus, andulu vocal mix on ibadan
  • When I Fall Weekender mix – A:Xus on Guidance.
  • Welcome Home
  • Two t’seven

You can find another copy on Steve’s critically reviewed music blog Scissorkick here.  It’s important to add that through this project I was able to get to know Steve much better; a man with astounding knowledge of all walks of music and immense passion for his friends, family, wife, and son.  All would be a better person by knowing him.

Alpo Can Ring Modulator

This is a ‘ring modulator’ similar to the one used in an ARP Odyssey… this version operates by the input of two square waves into a 4011 quad NAND gate. I didn’t have a 4011 available so in this version I use a 4001 quad 2-input NOR with two inputs wired to ground (low) instead of wiring the 4011 with two inputs wired to Vcc. If I did my logic correctly the 4001 works the same when wired this way. I included the logic tables on the schematic.

Ring Modulator Schematic

The two square wave tones passing into the gates are compliments of a simple op-amp square wave generator circuit. Information on how to wire one of these up is widely available on the web. Here’s one good resource. The original schematic and idea was found on simple-answer.com here. A brief reference to the ARP Odyssey and this ring modulator is mentioned on Wiki here.

Alpo Can Ring Modulator board top

Obviously this is in an Alpo Can. The circuit board can be viewed on Flickr (see link below) but it was pretty small so it had no trouble squeezing in there. The knobs were found on eBay for dirt cheap. The hardest part about modifying this can was getting the sharp edges off the holes drilled into the can. To get the top off without cracking open the dog food… and to be able to take the top on and off the can you’ll need one of these: Kuhn Rikon Safety Lid Lifter

More photos and comments can be found on Flickr here:

4001 Ring Modulator in an Alpo Can

Sound Samples:

Dry, without Effects

Wet, with effects

Crash Sync

The Crash Sync is a John Hollis design who’s schematic can be found here. There are dozens of examples of these on the web.  They’re pretty popular among DIY enthusiasts and not terribly difficult to throw together.  John’s site has a number of great projects that center around Op Amps and are very affordable to complete.

I typically use whatever components I have available, either bought or raided from old gear, so when putting a project together there are some inevitable changes.  In this project I used different Op Amps and added in a bypass switch (with lights of course) to pass the original signal.  As far as I can tell using a different op amp hasn’t had a noticeable impact on the sound of this awesome little box. Lastly, like all of my boxes so far, I haven’t wired them up for use with a 9V… which is fine for me, but others might find it an inconvenience.   See the full flickr set for detailed photos.

Many more photos and comments on this build can be found on Flickr here:

The Crash Sync

Sound Samples:
Before #1
After #1

Before #2
After #2


This is a follow up to previous works of a similar grain by members of Master Mosquito, this track brings forward similar sounds of past tracks. Smooth and melodic synths backed with down tempo rhythms and crisp layered guitars which create an ethereal soundscape suitable for any listener. This is one of my favorites which compliments the similar track named ‘Tallboy’ nicely.  Much thanks to Aaron Schultz (DJ DRM) founder of Bastard Jazz, and Jamie Roberts for making this complete.

Master Mosquito – Regalt