Juanito's Sweat Factory

 Hey everybody, this is basically a placeholder.

I'm developing a CV sequencer module! Four inputs with knobs, for parameters. Eight CV knobs for, like, setting the CV of each step. One button in the middle. Oh yeah, two buttons under the top left and right pots, y'know, like HorseDebt. Eight outputs, one Pure DAC analog, three PWM analog, four digital but there's spots on the PCB to add a capacitor for smoothing if you wanna write firmware that can put out more PWM signals.

EXCITING THING: this is a radically flexible module. At its heart is a AVR128DB64 chip, which can be coded in the approachable Arduino IDE, and there's even gonna be a USB jack right on the PCB so all  you need is this module, a USB cable, and a computer, and you'll set to program this little guy??????

I haven't even started writing code for this, but it's gonna be flashy, it's gonna be flexible, and it's gonna have TWELVE JuanitoPots with addressable LEDs under them. BlinkyFlashyBloopyFun

FZilter featuring a MB87186 chip

 

A mysterious forest wizard shot an arrow into a nearby tree trunk with a message wrapped around the shaft. It said "Wouldst thou deign to design a PCB for an exotic precious gem of a microchyppe which one canst obtaineth not except by exxtraction from a Casio FZ-1 or symilar keyboarde?" so I stuffed a message in a bottle saying "heck yes" and threw it on the water.

I had never heard of this chip or the fact that you can build it into a Eurorack module, but it's quite a unique thing. The chip is a "digitally" controlled filter and amplifier, which garnered some praise back when it was new for sounding analog. Turns out it IS more-or-less analog, with a switched-capacitor filter and hmm, I'm not sure how the audio amplifier is managed.

What is a switched-capacitor filter?????? Glad you asked. A filter is almost always a capacitor-resistor situation. A resistor reduces how much current can flow, and a capacitor can be thought of as a kind of balloon which "fills up" when a current flows into or out of it. Most synthesizers vary the resistance (sort of) to adjust the frequency at which a filter takes effect. You can do this with a potentiometer, which you need to turn with your hand like a cave man (ugh) or you can use a voltage-controlled resistive part like a Vactrol or an OTA which stands for operational transconductance amplifier obviously but just understand that it's MUCH easier to use a voltage to adjust the "resistance" section of a resistor/capacitor filter than adjusting the capacitor.