This is a great interview of an awesome figure in electronic music, done just recently (2011) in Madrid by the Red Bull Music Academy:
Listen to a free stream of Silver Apples of the Moon on last.fm.
Here we go… I’ve optimized the way I’m using power, love the way the dual jfet opamps (TL082) sound, and have the mixing elements mostly decided.
To be done on this prototype:
- use either capacitor switching or a simple 4017 sequencer to change up the textural possibilities of the oscillator
- add switches to the voice modulator to allow for “skipping around” pitches instead of only up or down changes
- CV input
I went through quite a few opamps before finally deciding on the dual jfets, and now I really dig how they’re working with the complex waveform of the four NAND gates (NTE4093)… I use it first as a multipole low-pass filter to shape the sound of the chained oscillators.
Because of the nature of the sounds I don’t find much use for the vibrato section of the voice modulator (HT8950), but don’t mind at all because it reduces the component count and I’m finding an incredible amount of possibilities already. You’ll also notice I’m using my fingers on a couple of resistors to change the pitch… I discovered this by accident, but really like the gestural aspect of it so much that I’m planning on building a touch interface into the final design.
The whole thing is finally mixed into another dual opamp, with a follower/buffer and a high-gain resonant Q notch filter to add some harmonics and really cool sweep possibilities.
Excited to have this core design done, LOVE playing with it! Now it’s just a matter tweaking and expansion.
Here’s something I thought I’d never see myself do in my own lifetime: build a synthesizer from scratch.
Actually it’s a simple design: 2 555 timers in astable configuration producing square-waves. This means it’s a burst of sound every interval, pretty annoying and not very useful except for maybe starting earthquakes. So to give it a little flavor, I put a low-pass, 2-pole filter on the output of each oscillator, using a traditional operational amplifier.
A bit over a year ago it started out as a learning experience for me, I had never gotten into building things with analog circuitry – although I dated a chick in college who was an EE, so I was vaguely familiar with a breadboard. As a result, my design is über simple, and in reality was the design I could “get to work” from the opamp (a weird beast in itself, I will be tackling it again soon enough).
After a lot of experimentation and research on the web (these days a DIY’ers first reference), I came up with a 2-rail power design that provided 9V for the oscillators and 4.5V for the bipolar opamp (just left of the battery in the schematic). Moving left, the 741 opamp (NTE941) provides a low-pass, 2-pole filter to the signal from the 555 timer (NTE955).
The cutoff frequency of the filter is controlled with a potentiometer, as is the pitch of the oscillator. You can also see my modification in the lower left for a “range” switch, which wasn’t on the breadboard prototype, but made it onto my final PCB because I think it adds a lot more interest and possibilities.
This was an intense project, no doubt. I got some training on soldering little kits that got made into sculpture, and I am a proud builder and owner of a bleep labs thingamakit, and have recently built the wave sheild for my new arduino board (which I haven’t quite gotten to work yet, so I hope it’s my programming skills and not my soldering skills).
As much as I tried to plan out wire distribution inside the chassis where the pots and switches would not interfere too much with the PCB, sure enough I drilled the holes sort of on the wrong end of the enclosure, so the edges don’t match unless I flipped it, and of course I only discover this after everything is screwed into the front. So, fixing it meant pulling all the knobs and switches back out, and removing the PCB from its mount on the inside and flipping it 180 degrees, then re-attaching everything.
In the end it really didn’t make that much of a difference and the whole thing came together fairly perfectly anyway. What I haven’t really done is add any decoration or labels, which I do want to do… inspiration will strike when I least expect it, perhaps it will not only get illustration but also a name, and it will evolve!
I’m excited to be waiting on the arrival of my new Bleep Labs ThingamaKIT.
Not unlike the simple improvising synth I’ve been working on with VCOs and 2-pole filters, this is a DIY version of their photo-sensitive thingamagoop, described on their website as simply:
“The Thingamagoops have oscillators just like any synth. On analog synths the oscillator that creates the actual tone you hear is called a VCO or voltage controlled oscillator. The Bleeps work a little differently so we’ll just call it the main oscillator. Instead of using a keyboard, the main oscillator in the Thingamas is controlled by a photocell.”
It’s basic, it’s clean, and best of all it’s amazingly well priced for the stuff included – as long as you’re in it for the soldering, of course, like nuts like me. There’s some good pics up on the thingamakit flickr group.
Looking forward to a good learning experience and possibly some ideas on how I can improve my homebuilt oddities.