Ironically, since I’ve spent so much time working on this project, I have not posted about it much—but I’ve spent a huge amount of my free time in the past two years or so building a complete analog synthesizer. From scratch. And now it’s really starting to come together!
I developed this automatic gain control (AGC) circuit to compensate for the -3 dB gain after each filter stage in a 2-stage, 4-pole voltage-controlled filter (VCF). I’m posting this because it was surprisingly difficult (rather, impossible) to find a low-distortion operational transconductance amplifier (OTA) driven AGC schematic I could use directly.
In Part 2 of the Precision Current Reference build, I assembled and calibrated the instrument and tested it out.
A precision current source like you’d find in an SMU would be a very helpful tool for some of my other projects. But an SMU costs an arm and a leg… my needs were not so great. Could I make what I needed without breaking the bank?
Over the past year I’ve gotten into building modular synth components. There’s a lot more to share on that front; I’ve put together several modules and have a plan for several more to go into an integrated system. The relative complexity means there’s a lot to write about, though, which has made me keep putting it off…
In the meantime, I completed a smaller project this weekend—a breakout board that makes it easier to develop audio circuitry on a breadboard.
I built my own circuit to handle conversion of 6 VDC power from the batteries to the 2 KHz AC power required by EL-wire.
I recently designed a custom case to fit a Raspberry Pi 4 and a 7″ LCD screen. I wanted a small tablet-like computer I could set up to look at while seated at a table, or standing at a counter in the kitchen.
Time to wrap this up… I was, in fact, able to get this successfully wired up and mounted on the boat! All in all, I had a great time making this project and learned a lot.
All the pieces have come together. It’s time to hook this up on the boat and see how it works!
Now it’s time to put it all together! Mechanical fabrication is one of my weaker skills and this is where having handy friends really helped pay off.
