modified Stereo Memory Man with Hazarai

Last summer a friend of mine gave me an old Boss DD3 digital delay pedal. I’d been looking to add a delay module to my modular synth and this guitar pedal fit the need pretty well. After playing with it for a few weeks I was wishing that it had some way to synchronize the delays with the beat of the synth. If you’ve ever used delay plug-ins with a DAW you know what I’m talking about. Most plugs that I’ve used allow one to choose delay times in milliseconds or in times related to the beat: quarters, eighths, dotted sixteenths, triplets, etc. Having some beat-synched delay taps hopping around the track really can add a lot in the way of syncopation. Having any delay, synched or not, is great. But that extra thing is what I was looking for.

I noticed that the several pedals have a tap tempo switch, which gets close but isn’t quite right for the synth. Tapping tempo is perfect for a guitar player who can subtly change speed to keep time with tapping a pedal. But the timing of a synth is much more machine-like in nature and would work best with the same clock as what’s timing the entire patch. If you’re running a sequencer, LFO, and envelope from a clock trigger, that same trigger could drive the taps of a delay and keep everything in time.

In an email to Navs, a musician in Germany, I happened to mention that a pedal with a trigger input would be a great thing. He replied with a link to a post he’d made on his own site about a year earlier. In this post, he writes about a musician, Rechner7, also in Germany, who had modified an Electro-Harmonix Stereo Memory Man with Hazarai (Hazarai is a Yiddish term meaning something along the lines of “everything and the kitchen sink”). Rechner7 had not just added a trigger jack, but he’d added three of them with a switch to choose between the 2nd and 3rd inputs, as well as a on/off switch for the loop button which would make that particular function much easier. I’d never soldered a thing in my life but onto Craigslist I went and a week or two later had a SMMH pedal.

Aftr studying Rechner7’s photos and a few emails back and forth, I understood a bit more of what was going on. Trigger/Gate input C on his plans is always on, and there’s an on/off/on switch that chooses to add input B or A to the signal at C. This allows a steady beat into C with odd or random beats into the other two inputs, which can add a lot of fun/chaos to the delay signal. The SMMH doesn’t repitch when the delay is sped up or slowed down (its only weak link in my opinion) so having these two inputs is terrific for quickly adding new taps or off-beat taps. He also added a little high-pass filter circuit (found about a third of the way down on Doepfer’s website here) which keeps a slow gate from inadvertently engaging the loop function. On the SMMH, the tap-tempo switch engages the loop if pushed for more than a half-second. What this means is that a long gate (half second or more) would do the same. So the high-pass filter only allows gates that are shorter. The exact length is decided by a capacitor and some math. (I apparently didn’t do the math correctly because mine still slips into loop mode now and then. I need to fix this.) There’s a switch that bypasses this filter for inputs B and A in case one wants to throw the thing into loop mode. Lastly, Rechner7 also suggested I add a transistor to the input circuits, which keeps unwanted voltage from traveling back to the trigger source on the modular.

I wired this all up on a breadboard before doing any permanent damage to my new pedal, and was quite surprised when it worked. Confidence flowing, I took the step of drilling six new holes into the aluminum case of the SMMH. This was rather thrilling in a DIY sort of way. There was no going back now.

101114_smmh mod_022

It took the better part of the next day to get the wiring done and everything in place, and I’ll be the first to admit that my electronics work isn’t the prettiest. But the results are exactly what I wanted. The only change from Rechner7’s design was that I designanted the always-on jack as input ‘A’ rather than ‘C’ which just made more sense to me.

101115_smmh mod_035

Here’s a short track where the different delay timings are really apparent.

One thing I’d not considered was that when the delay lands exactly on the beat, it’s not that interesting. So I find that using the Rotating Clock Divider from 4ms is necessary. A typical patch would be using the /3 output from the RCD as the main clock, and running the /1 and /2 into the inputs of the SMMH gives me triggers on the eighth-notes and triplets. Then I might have something more unusual running to my input C for some chaos tossed in.

Edit: I should probably mention that on the video up there, the same rather boring eight-step sequence is spit out by the synth throughout the entire video. All the syncopations and funny beats and extra rhythms are created entirely by the Stereo Memory Man being clocked by the µStep, a little trigger sequencer from Intellijel. The dry signal is on the left channel and the wet is on the right, so you can listen to just one or the other and hear the differences.

Since completing this mod, I noticed that Rechner 7 had done a similar modification to an EHX Deluxe Memory Boy as well. I’d been thinking about adding an analog delay pedal to my arsenal, and found a used one a few weeks ago. About the same time, Pittsburgh Modular announced an analog delay module for Eurorack that may end up being more what I’m looking for, even without tap tempo, so I’m holding off drilling the holes into the DMMB in case I need to let it go.


Built a small breakout module for my 4ms Rotating Clock Divider over the weekend, and spent some time playing with it. It’s got six switches that allow one to change some counting and reset behaviors of the RCD which previously were only available via jumpers on the PCB. I spent an hour or so afterward making some music and recording. While I was very happy with the results, I realize now that it’s kind of hard to hear what the breakout is doing in these two tracks. So instead of going into the RCD/Breakout and explaining the results, I’ll just post these guys for your listening pleasure.
The description on Soundcloud is as follows: The e350 Morphing Terrarium on the bass with an Anti-Oscillator FM’d by an Unkle Oscillator on the higher pitches. Note CV is from a Noisering through a µScale quantizer with the scale notes and intervals shifting. Pressure Points is the modulation sequencer. The delay on the high pitched part is from an EHX Deluxe Memory Boy set to dotted eighths. I love that delay pedal.

I’ll record something later this week, maybe, that better shows off the abilities of the RCD and the breakout.

science fair box

My daughter decided that she wanted to make something out of electronics for her fourth-grade science fair. For the project, the kids have to come up with a question for which an answer can be hypothesized, and then proven or disproven with an experiment. Elliot, on her own, came up with the question “how does electricity move in a circuit?” This is a rather big question for our limited knowledge of electronics-building in this house, and I wasn’t sure whether we could actually answer the question with a few resistors and some stranded wire. ALas, her teacher approved it. Furthermore, the job was made even more complicated when Elliot’s answer was “I think it is heat.”

I gave Elliot a few books to read, and she took to the Make:Electronics book by Charles Platt. I had bought and/or read a few books before ordering this one and it’s by far the best I’ve found. Apparently, Elliot agrees as she pretty much memorized the first few chapters. I can’t tell you how much fun it is to sit there with a ten-year-old girl and have her thumb through a pile of resistors looking for the 220ohm one as she studies the color codes of the resistor’s stripes. I showed her how to read a multimeter (something I just learned a few weeks ago), and she was off. She built a few simple circuits using the experiments in the book, trying out different values of resistors, various colored LEDs (it was cool when we burned one out and the room smelled like an electrical fire), and four AA batteries.

"Crazy Labs"

It wasn’t long before she was working out ways to have a switch to flip between different colored LEDs, and she asked how to add a knob (potentiometer) to dim the LED. For the science fair experiment, she merely recorded the volts and amps of the circuit with various resistors, and deduced the wattage produced with these numbers. I think she realized what I was worried about with her hypothesis, which was that “I think it is heat” isn’t really an answer to her initial question. The answer has to do with electrons and conductivity and positive/negative forces, but that’s a little deeper than we were able to go with a Radio Shack breadboard.

I wasn’t comfortable sending her to her science fair with the breadboard and all these wires and things (fourth grade boys can be jerks you know), so using one of the circuits she’d worked up, we got a small plastic box from Staples and I soldered the circuit together using a bigger battery (9v) and a stronger potentiometer (50k), along with a huge switch.

Elliot's science fair circuit

(This is the circuit before soldering it to a circuit board and putting it the little clear box to the left. The big switch flips the red or green LED on and off, and the knob thing dims the red LED.)

the science fair box

the science fair box

I was pretty excited when I turned it on last night and it worked. So excited, in fact, that I made a little movie with music from the modular synth.

Now I’m really starting to make plans for odd little projects for myself. For instance, I would like to have a small module for my synth with two clock sources, each voltage-controlled, and have a switch which can sync them or let them run free. I found some plans online for one that uses a basic 555 timer chip, so I think that might be my holiday project…


When I went down this modular synth hole about a year ago, I distinctly remember thinking to myself that while I’m okay with the modular nature of modular synths, I’m not okay wit the Do It Yourself aspect of electronics and I had no interest at all in any of that. i didn’t care what was a resistor, I didn’t plan to learn to solder, and it didn’t bother me that I didn’t understand the difference between hertz and amps and volts and ohms.
Now, if you know me, you know that these kinds of thoughts can be accurately put in the “famous last words” category. For the last several months I’ve been planning all kinds of soldering and circuit mayhem, starting with a build-it-yourself control-voltage joystick kit that I bought, that needs a minimal amount of soldering, but lots of planning to go into a metal box correctly (picture of the kit here). I also have a few books now that describe various interesting handmade musical instrument projects. And (oh yeah) several years ago, I had the kids collect all their funny electronic musical toys and we’ve had them sitting in a box here at my studio, waiting to be bent (including a complete set of Speak & Spell, Speak & Math, and a Speak & Reads).
So this last Sunday, I dragged the childrens up to New York City to Culturefix, a small bar/studio/gallery on Clinton Street, just below Houston. Create Digital Music was throwing a little Handmade Music fest there, and they were having a workshop where one can learn to build a very simple, seven-component theremin-type device. Since I’ve had these books and the soldering gear for several months, I’d yet turned it on and still wasn’t sure what to do when I did. So I signed up and took the kids.

Handmade Music: Phototheremin workshop
Handmade Music: Phototheremin workshop
Handmade Music: Phototheremin chorus performs

Here’s a not-great little movie of the theremin chorus, after we built the things.

It was a real nice time. Peter and Cole made space for us, everyone was friendly, and Wilson and Elliot were interested. We built two kits, one of which had its transistors reversed and needed some desoldering (so I learned to do that too!). But in the end, we got two working teensy theremins (sounds and video to come soon).

tiny little handmade theremins

And, of course, I think this is just the coolest thing. Now I’m thinking of all kinds of crap I want to make, and when a friend of mine asked me how he might put some push-button sound sources in some space-ship sculptures he’s putting together, I immediately decided that this will be something worth figuring out. It won’t be too hard to build small circuits with buttons and potentiometers that make spacey sounds, will it?