My rack is a mix of Eurorack Modular and Korg Volcas. It's always changing but usually looks something like this.
This is a crappy but functional VCA I built. While VCA does technically stand for Voltage Controlled Amplifier, it doesn't actually amplify anything.
This Voltage Controlled Filter isn't great, but it does work and I learned a lot from building it.
Diagram for my VCF
This is a dual Low Frequency Oscillator built around a 556 timer chip. While it is a bit crude it does the job just fine.
I built this to allow me to route audio signals in and out of my modular rack. Eurorack uses a much hotter line signal than most other gear like my Korg Volcas, so it's important to shift the levels when going in or out of the rack. A signal put into an input can then be taken out in either a boosted (going into the rack) or attenuated (coming out of the rack) level.
These are some early custom modules I built. The Gates of Moria is a VCA, although I didn't know what those were when I built it. I just needed something to stop the signal from my oscillator when I let of the key and I felt like it should have a wizard on it.
Synthesizers
I enjoy both playing and building Synthesizers.