ESP32 DAC Envelope Generator – Part 2

Following on the back of my ESP32 DAC Envelope Generator and in particular my note at the start that it was essentially the code algorithm and none of the electronics that might make it useful, I started to try to find the simplest possible circuit that Just Might Work as a voltage controlled amplifier (VCA) for …

PICO2/AFPOC

February saw another momentous step in the ambitious John Cage Organ Art Project at Halberstadt when the playing chord changed for the first time in two years. The resultant chord will now continue to play for another two years before the next change. The project is a performance of John Cage's ORGAN2/ASLSP, generally known by …

Diagnosing and attempting to fix a Yamaha DX100 – Part 2

At the end of part 1, I've established that the basics all seem ok (PCB, interconnections, power) and that basic digital logic stuff is happening. I rounded off my write-up with the following ideas for what to investigate next: Get some proper triggering from the chip enables to check for valid data signals. Check out …

CD Rack Format Zynthian – Part 2

I've recently updated my "CD Rack" box to a horizontal black box, still shaped for my "CD Rack" format modules. But as it is black, and I've a black TX816, I've rebuilt my CD Rack format Zynthian with a black, PCB front panel too. Original Design Notes: CD Rack Format Zynthian. Warning! I strongly recommend using …

Raspberry Pi Pico Synth_Dexed? – Part 6

One last thing I definitely wanted for my PicoDexed was the option for PWM output. This post is by way of a short coda detailing how to do PWM on a Raspberry Pi Pico. Part 1 where I work out how to build Synth_Dexed using the Pico SDK and get some sounds coming out. Part …

Raspberry Pi Pico Synth_Dexed? – Part 5

Ok, ignore my last comment about Part 4 being my last post on this topic. I thought I ought to pull together all the hardware notes on how to build one as I haven't really written that down anywhere. So this shows the connections required between the Pico, I2S DAC and MIDI IN. Part 1 …

Raspberry Pi Pico Synth_Dexed? – Part 4

I was going to leave things at Part 3 blog-wise, and just get on with filling in the gaps in code now, but I've come back to add a few more notes. But this is likely to be the final part now. Recall so far, I have: Part 1 where I work out how to …

Raspberry Pi Pico Synth_Dexed? – Part 3

The story so far... In Part 1 I work out how to build Synth_Dexed using the Pico SDK and get some sounds coming out. In Part 2 I take a detailed look at the performance with a diversion into the workings of the pico_audio library and floating point maths on the pico, on the way. …

Arduino EEPROM Reader PCB Build Guide

Here are the build notes for my Arduino EEPROM Reader PCB Design. Warning! I strongly recommend using old or second hand equipment for your experiments.  I am not responsible for any damage to expensive instruments! If you are new to Arduino, see the Getting Started pages. Bill of Materials Arduino EEPROM Reader PCB (GitHub link below). 2x …

Arduino EEPROM Reader PCB Design

This is a PCB version of the Arduino EEPROM Reader/Writer as described here: https://github.com/beneater/eeprom-programmer but with slight adjustments to support reading of 27Cxxx style ROMs often found in vintage equipment. Build Guide here: Arduino EEPROM Reader PCB Build Guide. Warning! I strongly recommend using old or second hand equipment for your experiments.  I am not responsible …