A thorough and nice no input mixing tutorial by Sarah Belle Reid (2019).
Build a perf-board unit of the a Simple EQ / Baxandall EQ module (the Tilt channel is still in the making). The build was an ordeal. I did how ever learn that the reverse polarity protection of the circuit works well (it even saved an IC I popped in the wrong way) and that my noisy DC 5-24v to Dual Power 12v -12v 5v -5v 3.3v supply is robust. I attempted to plan the build using various board design tools (Fritzing worked best for me) but ended up just soldering components down following the schematic.
I added two switches to my build, which can be used to bypass the capacitors controlling the bass response (27nf) and/or the treble (1nf). Changing the 27pf didn’t have much effect. I added female pin headers which can be used to insert different capacitors in their place. My first water capacitor (using faux s.pellegrino) shows a value of ~35pf and it has an effect on the sound. Next I’ll build more water capacitors, which hopefully will have higher values for more distinct effects. I’ll also have to design a front panel, which can used to mount the bulky capacitors (The one I have has ~20ml of water in it).
During my tests I’ve discovered that the electrical resistance of sparkling mineral water drops slowly (as the water loses its bubbles). I believe that this property could be used as vca of sorts. I plant to make a simple signal divider, which uses sparkling mineral water as a conductor. This signal multiplier would be useful for one-shot slowly amplifying ramps (for example adding volume). Water and electronics is a beautiful combination.