DrooOone Circuits

[PHOBoS]

Recently egasimus asked how to make a common detune control for
multiple 40106 oscillators. One obvious thing that came to mind was
using vactrols. Of course the oscillators won't detune exactly the same
which can be very useful for creating droney sounds.

My initial idea was to take a PWM controlled 10mm LED and place 6 LDR's
around them controlling 6 oscillators (40106). I did some experiments and
eventually ended up with using only 2 vactrol controlled (or is that vactrolled ?!)
oscillators.

So here's the first circuit: "3240106 Droner"
- It has 2 oscillators to set a base drone one of which is slowly and slighty
modulated by a triangle wave provided by a third oscillator.

- Then there are the 2 vactrolled oscillators. The vactrols are driven by
a PWM controller which in turn is also modulated by a triangle wave.
Modulation depth and speed can be adjusted. The 100k trimpot is to set
the offset to get a nice vactrol responce. I made mine from a ordinary
5mm red LED, a LDR and a piece of heat-shrink tubing.

- The oscillators are passively mixed together using resistors and I added
a small cap to make the sound less harsh.

The enclosure is probably temporary as I'm planning to build a couple of
drone ciruits and put them together in a box with a mixer, delay, filter and
what else might be useful to create some nice drones (tips are welcome!)
I'm thinking of adding a cheap circuit bent keyboard aswell.

here's the schematic, a photo and some demos:

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PHOBoS - 3240106 Droner Demo - hands off (Jun. 11, 2011).mp3
Description:	Letting it drone on it's own
Filesize:	2.48 MB
Duration:	2:43
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PHOBoS - 3240106 Droner Demo - pots (Jun. 11, 2011).mp3
Description:	Turning some knobs
Filesize:	5.39 MB
Duration:	5:53
Viewed:	4092 Time(s)
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PHOBoS - 3240106 Droner Demo - delay (Jun. 11, 2011).mp3
Description:	delay added
Filesize:	2.14 MB
Duration:	2:20
Viewed:	3914 Time(s)
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3240106 Droner.gif
Description:	PHOBoS - 3240106 Droner schematic
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3240106 Droner.jpg
Description:	PHOBoS - 3240106 Droner build
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[PHOBoS]

For the second droner I experimented with a XOR ringmod, which resulted
in the following circuit: "XOR Stereo Droner"
- as with the previous circuit this one also has 2 oscillators to set a base
drone, but this time both are slowly and slighty modulated by a triangle
wave. The outputs are attached to an XOR. What I didnt know before is
that if you add an LED to the output it will fade in and out in sync with the
frequency shifting produced by the 2 oscillators. So this is also very
usefull to use in future drone circuits as an indicator.

- I used this fading effect to modulate a third oscillator which is also XOR'd (?)
with the other 2 oscillators.

- with so many outputs and a spare inverter I decided to make a stereo
version. Mixing is done in the same way as the previous circuit but I did
use different resistor values for the XOR outputs and the direct oscillator
outputs.

schematic, a photo and some demos:

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PHOBoS - XOR Stereo Droner Demo - hands off (Jun. 11, 2011).mp3
Description:	Letting it drone on it's own
Filesize:	5.02 MB
Duration:	5:29
Viewed:	4026 Time(s)
▶ Play   ⇩ Download

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PHOBoS - XOR Stereo Droner Demo - pots (Jun. 11, 2011).mp3
Description:	Turning some knobs
Filesize:	3.66 MB
Duration:	4:00
Viewed:	3969 Time(s)
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PHOBoS - XOR Stereo Droner Demo - delay (Jun. 11, 2011).mp3
Description:	Delay added
Filesize:	6.36 MB
Duration:	6:56
Viewed:	3945 Time(s)
▶ Play   ⇩ Download

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XOR Stereo Droner.gif
Description:	PHOBoS - XOR Stereo Droner schematic
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XOR Stereo Droner.jpg
Description:	PHOBoS - XOR Stereo Droner build
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[PHOBoS]

If anybody has some nice drone circuits please post them.
here's some that are probably well known:
beavisaudio Heterodyne Space Explorers
Casper Electronics Drone Lab V2

[tjookum]

Awesome stuff Phobos!

Almost missed this one since I rarely venture outside the lunetta forum...

I really like your ideas and your schematics look great, definately going on my backlist. And about controlling the offset, have you seen this?
http://electro-music.com/forum/topic-48083.html
I think that is a beatifull way of making a drone with minimal controls.


I've also been heavily focussed on Drones lately and they are just endless fun. Im working on the second version of my Organ Dronor and Im really learning a lot about filters and mixing. One of my favorites is to mix the oscillators together with diodes instead of resistors, really adds more flavour.

I don't have a finished schematic but I added a little taste of the dronor. Im using some very old diodes from a power supply wich tends to sustain the drone longer but any diode will do. The little added circuitry in grey changes the output from ramp to triangle to saw. You can also add diodes across the variable resistors on the oscillators with the same effect.

here are some of my drone explorations:


and a lot of recordings, some more succesfull then others:
the Organ Dronor by Tropical Benny

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organ dronor V2.1.png
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[v-un-v]

Thanks very much for posting these Phobos. I've been lusting after a nice drone box ever since I clapped ears on the Drone Commander. I'd love one of those, but not at that price

[madtextureenvy]

Thanks for posting PHOBoS.
Amazing, as always and your sharing is much appreciated.

Any other electro-music denizens built these yet? So much fun to play a bit, then nap while it just drooooooooones.

[PHOBoS]

The only build I know of is the PharaohDrone by RingMad which uses the XOR Stereo Droner.

https://www.youtube.com/watch?v=jg4Acgn6kGM

[madtextureenvy]

Here is a very short video of the final product punched through a DiYstortion.

https://youtu.be/MwYxM-nXQ5w

Thanks again PHOBoS!!!

[PHOBoS]

awesome!

(btw I did add values to the perf layout but it wasn't really great to begin with,. looks like you didn't need it anyway )

[Schläfer]

Hey hey,
First post here, lurking in the shadows since a while though

Just wanted to share my build of one of the Phobos droner design (thanks for the schematics !)

I took the 3240106 Droner and added the filter section of the Casper Electronics Drone Labs (low pass into distortion into 2x resonant band pass filters, with audio input)

Nice textures are going out of this thing !

Here a sound example, with just a delay added, feedbacking into the audio input: https://soundcloud.com/user-624222268/otoro-drone-02

And a pic of the thing (etching of the panel in process)

So, thanks again Phobos, and Casper, for the inspiration, much apreciated

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[PHOBoS]

Looks great! and sounds good too, pretty agressive I guess the distortion might be responsible for that.
It brings me a lot of joy to see that the circuit is useful to you and nice to see it combined with some circuitry by
Casper Electronics, who has made some awesome things (the Drone lab being one of them). I hope you'll have a
lot of fun with it.

[L´Andratté]

That´s heavy stuff, schläfer, and a very nice build, also thanks for resurrecting this thread which had escaped me!

[PHOBoS]

Now that I looked at the circuit again I think you could replace the 100K mix resistors with different values which would
result in a waveform with more steps. You could go a step further and replace them with potentiometers. A simple output
buffer might not be a bad idea either.

[Schläfer]

Thanks!

I added an output buffer already, was thinking to add potentiometers for the volume of each oscillators, but the panel was getting a bit full already, and i like it like it is i think

Another track with it, same setup, dronebox -> delay -> feedbacking into its audio input, less noisy this time.

https://soundcloud.com/user-624222268/otoro-drone-01

[Grumble]

Originally I designed this module for Calculating chord progression with an Arduino and though the idea isn't dead yet, I reprogrammed this module trying to create a drone.
Have no recording but will add that soon.

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triades schema.pdf
Description:	The schematics have changed a little: The LED's are substituted by 3 color leds.	Download (listen)
Filename:	triades schema.pdf
Filesize:	174.88 KB
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[Grumble]

This is a drone made with the previous schematics.

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drone02.mp3
Description:	MP3
Filesize:	6.96 MB
Duration:	5:04
Viewed:	3310 Time(s)
▶ Play   ⇩ Download

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[gasboss775]

PHOBoS It is possible to modulate all six of the 40106 oscillators by modulating the power supply to the chip, the only problem is that this also varies the amplitude, although it is possible to correct that if desired.

The frequency of the oscillations is inversely proportional to supply voltage, that is increasing voltage causes decreasing frequency and vice versa.

[PHOBoS]

I haven't tested it, but yes that should work. They probably won't stay in tune though if you change the voltage
(in relation to each other that is). However, if you're planning to built the XOR Stereo Droner and you only
adjust the supply voltage for the 40106 gates their outputs might not be high enough to trigger the XORs
but it shouldn't be a problem to just lower the total supply voltage. hmm, U1b probably won't be very happy either
if it gets a higher voltage on the input coming from U2d. The 3240106 Droner has the output of the opamp optically
isolated from the 40106 gates so that one should work fine with adjusting only the supply for those gates. Power
starving might give interesting results too but it will definitely reduce the output level.

(hmm, I still haven listened to the sounds posted by Grumble eventhough I have this thread open in a tab since
they were posted )

[gasboss775]

I made a complex waveform generator using a 40106 as six oscillators combined in an inverting mixer with diode clipping that in addition to producing complex intermodulation products ( creating a sound almost like noise ) ensured a more or less constant output amplitude even though the 40106 was fed a wide range of supply voltage ( in order to provide overall tuning ) by the opamp mixer. The inverting characteristic of the mixer corrects the inverse frequency voltage characteristic of the 40106.

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t_complex_waveform_generator_131_1_873.png
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[Schläfer]

looks really nice, but the picture is just too small to be able to read (at least for my eyes )

[gasboss775]

[gasboss775]

OK this one is larger and easier to read:

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complex_waveform_generator_131_1_873.png
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[gasboss775]

Here is the general idea and another method of normalising the output amplitude :

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Schmitt VCO.jpg
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[Schläfer]

Thanks, way better !

[PHOBoS]

I thought about using a comparator myself as a transistor inverts but for audiofrequencies that doesn't matter much of course.