Friday, 28 May 2021

Passive Modules

Finished guys
It looks like it has been a year since I built my last DIY module.
Time for some passive modules I guess.

I ordered two 2-hp blank.  I needed another multiple to fill the rack and I decided to experiment with some passive functions.

A passive multiple is very basic.  You simple connect the tip and ground of each jack.  In practice the ground connection is established via the aluminium panel.  No need to use wire.

The main difficulty here is at 2-hp, or a bit more than 1 cm width, you do not have a lot of margin to drill your holes.  You do not want the body of the jack to go over the edge.
Not perfect but good enough.
I used mostly very cheap jacks I got a long time ago, except for the one with the switch as the switch on the cheaper ones is really terrible.

Behind the scene

Bob at work with the panel
I also experimented with some minimal panel marking by using my Dremel to carve some traces and fill them with a permanent marker.  This should not age very well. Time will tell.

The second module is the combination of a passive OR and a half-wave rectifier, ideal to combine gates and manipulate control voltages or distord audio.  You’ll find  the layout for both of them at the end of the article.  I got the schematics from unrecordings! blog

In the rack

In the following piece, the Korg SQ-1 produces two tracks of gates and CV for the kick and hi-hat.
I used the multiple to distribute the gates everywhere in the synth and I used the OR function to build a third melodic track from the first one and the output of the Turing Machine,  clocked by the second track.  I know it sounds complicated.  Patch schematics is at the end of the article.
The half-wave rectifier produces some overtones to spice up the sounds.
The variations in the piece is me playing with the sequencer.

Connection layout

Patch of the day

Sunday, 11 April 2021

Emilie's Last Stand

So I got Beads.

Not the decorative string of pearls, the Eurorack Module from Mutable Instruments.

To be more specific, Beads is the last design from Emilie Gillet, founder of Mutable Instruments.

Just unboxed

Powered by ARM

Beads is a revisit of Clouds, maybe the most successful Mutable module.

I always thought I'd get one one day.   Alas Emilie discontinued it more than 3 years ago.  Beads development took more time than expected, which created frustration and anticipation among Eurorack aficionados.

Beads, as Clouds, is dubbed a "granular texture synthesizer".
Basically, Beads samples its input continuously and creates tiny bits of sound or grains.
Up to 30 grains can be created and processed.  


From the manual :
One way of picturing how Beads operates is to imagine a tape loop, on which incoming audio is continuously recorded.

Every time you request a grain to be played (in reaction to a trigger, a button press, periodically, or randomly), a new replay head positions itself along the tape.

If this replay head doesn’t move, the audio will be played back at the original pitch and speed, but if it moves closer to, or further away from the record head, the signal will be replayed at a different speed and pitch. This replay head has its own amplitude envelope, and it will leave the tape once the envelope has reached a null amplitude.

Now imagine up to 30 replay heads flying along the tape. Imagine you can stop the incoming audio from being record- ed on the tape so that all these little replay heads can freely move along and gather sounds. And there’s a reverb…

Bob unscrews previous module

The module manipulates the density, size and shape of grains, as well as the time and pitch of the replay.  In certain modes, this is a reverb, or a delay, or both.
Grain density can go up to audio rate, creating new sounds in the process.

I thought it would make a great addition on my most ambient patches.  And with 14HP, it perfectly replaces my home made phaser effect module.

In place

Here is a small example of a drum loop made with the synth going through Beads in the Sunny Tape audio quality.
First you hear the sound unaltered.  Then Beads comes in progressively.   Grain seed is in sync with the drum sequencer.  You first notice the reverb as grain density start from very low. Then the grain density increases.  With small grains and low density, you hear the individual grains.  
I play a little bit with some settings and go up to 100% wet on Beads.
Finally, I select the random mode for grain seeding and I slowly bring back the unaltered sound in the mix.

Here is the full patch :