Elektrosluch!

Hey everyone! With the release of my electromagnetic sound library on the horizon, I wanted to share some of the process of building an Elektrosluch and recording the sounds. For those of you who don't know, an Elektrosluch is a type of induction coil pickup. These devices pick up electromagnetic fields emitted by electronic devices, if it's got power it probably sounds cool.

The most common version of this device that I've seen is produced by LOM. They have various versions and a DIY kit. I'm not sure about you, but I have never been lucky enough to see the store page with an 'in stock' label on it. Some lucky colleagues have snagged one or two in passing but I could never seem to find the window. Fed up with waiting I discovered that the schematic is open source! LOM even links Makezine.com in their FAQ, parts list and instructions included. I have decided to draw my own diagram that labels each part so you don't get lost referencing back and forth of what capacitor goes where. I'll include the schematic for polarity reference, I'm not very adept at reading those kinds of diagrams so the placement diagram helped a ton.

So to start off you're going to need some tools; soldering iron (solder+solder wick), wire stripper and wire cutter, voltage meter (not 100% required but helpful to find faults in your soldering) and finally some sort of drill to drill out some of the PCB board holes. Some components wont sit or fit through the pre-drilled holes so some modification is needed depending on what components you buy.

As for parts, I tried my local electronic supply shop and they only had a portion of the parts that I needed. I found everything on Mouser.com  and they'll ship any quantity to you of any part. I ordered some electronic project housing from Amazon to throw it all in.

PARTS LIST:

1. PCB Board
2. 1kΩ 1% metal Resistor x2
3. 100kΩ 1 % metal Resistor x2
4. 390kΩ 1 % metal Resistor x2
5. 2.2µF 10V Capacitor x4
6. 100µF 10V Capacitor x2
7. 2.2mH Vertical type Inductor x2
8. IC Socket, 8 pin DIL x1
9. Op-Amp IC chip (OPA2134) x1 
10. Stereo Jack
11. 9v battery and battery connector
12. hookup wire

I won't go step by step as Makezine does a great job going over it. I personally didn't follow each step and just followed the diagram. To the right is the reworked diagram from Makezine but with labeled components. Black lines connecting each part is solder lines. My build included a on off switch and a LED light to show me it was powered, these can be placed between the 9V battery and the rest of the circuit. I used a 3 pin switch so just connect the red and black cables to the side you want to be on and nothing to the one you want off. The LED gets soldered to the same points. I also have a 9V holder that is mounted inside the case, you can get these from Mouser as well. The red, blue and green wires are jumper wires so take a bit of wire from your wire spool to make those connections. As far as the housing goes, I custom drilled holes for the inductors at the end, the side LED and the switch to be fit snuggly to the case. You don't need any of this but I wanted it to be portable and did not want to risk getting components caught and ripped apart.

Here is the original diagram included on Makezine.

Some things to be mindful of; even though I have an on/off switch leaving the 9V battery in the circuit sucks it dry of power. I have yet to understand why or how this happens but I just end up popping it out when not in use. I plan on getting rechargeable 9Vs cause man are they expensive! The stereo jack is a 3.5mm connector so youll need an adapter to plug into your interface/recorder. You could use a 1/4 inch mono jack but the room it takes up would make you rethink the enclosure. Take your time, step away for a bit, it'll help you focus.


If I were to do this build again I would probably etch my own PCB board as soldering on a generic board requires some time to make all those connections. It would keep it cleaner and less of a prototyped mess. I'd also like to have some sort of enclosure that's a little more ergonomic. Maybe even had a quick release 9V holder akin to those for active guitar pickups. I would also add a volume knob (you can see where I drilled a hole in this build) but I ran into trouble with the entire circuit and decided to get the thing working and just abandoned the Potentiometer. Next time for sure. Also would add a mic stand nut on the bottom to be hands free.

Here are some audio examples and quick video I threw on Twitter the other day! Thanks for taking the time to read this and I'd love to see what other people come up with for designs!

I love this little rig, can't seem to get enough of the chatter! Unedited recording of some computer hardware #alwaysberecording #sounddesign #gameaudio pic.twitter.com/CGNkdc8SNW

— Derek Brown ➡️ GDC (@SubwooferSub) February 19, 2018