This is the latest nightmare of wires and microcontrollers, my MIDI pedalboard controller to route clock and program change round the two pedalboards. When (if) finished it will (should) allow me to use the RC-500 Loop Station as a master MIDI clock for all the pedals while receiving program change from the BOSS GP-10. Those program changes select a "super patch" from SD card on a LOLIN D32 Pro ESP32 MCU which selects different program changes for the three Eventide pedals.
I originally planned this with a web interface using ESPAsyncWebServer and JSON but that's been scaled back due to lack of available memory but it may just expand into a second ESP32 board to provide Wifi connectivity and web front end. A work in progress.
I've been taking a break from analogue circuits to investigate the world of DSP using an ESP32 microcontroller and the Faust DSP librares. This has been quite an adventure involving building my first dedicated Linux computer with PlatformIO running in Microsoft VS Code. So far I've got it running three sawtooth oscillators, a noise source, triangle LFO, amplitude and pitch envelopes and a simulated Moog resonant filter. The I2S interface produces impressive 24-bit sound quality at 48kHz sampling rate. Unfortunately the Faust delays and reverbs seem to make the processor brown out and it goes into a reboot cycle. More work required. Or possibly just a lot more memory. That couldn't hurt. The crackling noises are due to having the record level turned up too far rather than any problem with the synth.
Well, we're all confined to our homes while the COVID menace stalks the streets so here's a good old blast of insanely resonating modular synth with some 808 drums from Native Instruments Battery.
Just got this one completed and working. Uses the classic (reissued) CEM3340 chip as used in so many classic synths like the Sequential Prophet 5, Roland SH-101 and many others. The PCB wasn't quite right so I had to bodge wire a resistor and capacitor into the CV mixing section, not really worth fabricating a new PCB though as the finished module works very well.
What to do, what to do. I just can't decide.
I know. I'll make strage noises on the modular.
Made this today for a friend who's going to see Nile Rodgers in December, I thought it would be good to pre-empt the occasion by dusting off a few of my favourite guitars with one of my favourite riffs.
After several failed PCBs, we now have a working version that reads frequency from the modular! So far I've burned out four Arduino Nanos and a 20x4 LCD display module but we're getting closer to a working unit all the time. Next step is writing the rest of the firmware for the Nano to control the DAC and the 4066 switch.
Yes, it's another new (old) guitar. This one has been a "Holy Grail" guitar for me for a long time. I used one back in the 1990s in a studio in Newcastle and I always remembered it being a great guitar. Turns out they were built for Casio in the Japanese Fuji-gen Gakki plant that made the Japanese Fenders of the 1980s and the neck contour is exactly the same as my E-series MIJ Stratocaster.
Unfortunately, someone's done amateur repairs to this and soldered it up with jam and a hot spoon so the MIDI circuit is dead as a doornail and not coming back. No matter, I may even retrofit a Roland GK kit into this and have the world's coolest 90s tech guitar.
I stumbled across a video demo of a clone of the Buchla LPG on Youtube and was phenomenally impressed. So much so that I knew I had to build one. It's an ancient type of filter using Vactrols, a combination of an LED and a light-dependent resistor to effect a frequency response change. And it sounds wonderful.
The first PCBs aren't quite right, I managed to omit the two voltage tracks to the ICs so this first version is patched up with a couple of bodge wires to make it work. Only smoked one opamp making it, a new record.
Just arrived this week, an eBay special. The Novation Supernova has always been on my list of interesting virtual analogue synths so when I was looking for a Roland JP8080 and this popped up instead I didn't hesitate.
And it sounds bloody great. Absolutely pisses on the old MS2000, the filters sound really good (for digital filters that is) and it's got a really nasty clanky edge to it. Not figured out the arpeggiators yet but I've managed to get the LFO to sync to MIDI clock already. So that's good. And it would appear to be eight-part multitimbral. So I can can eight different programs playing in each performance patch. All with their own arpeggiator. No built-in sequencer but I never use those anyway. Brilliant piece of kit. genuinely dirty-sounding filter which reacts in a pleasantly surprising way as you crank the cutoff up.