After experimenting with digital sound generation, I wanted to go fully analog again — this time with the Doepfer DIY Synth project. The goal was to create a single PCB and front panel that integrates all the core analog blocks — VCO, LFO, VCA, ADSR, and Slew Limiter — into one compact and fully patchable module.
Concept
The original Doepfer DIY Synth is an excellent foundation: high-quality analog circuits with great flexibility.
However, it normally requires lots of external wiring — patch cables, front-panel routing, and connections between modules. I wanted to simplify this by designing a custom PCB that combines everything neatly in one place, ready to power up and play.
PCB Design
I designed the board from scratch, keeping the official Doepfer schematics as a base.
The PCB includes:
- VCO (Voltage-Controlled Oscillator) for generating rich analog waveforms
- LFO (Low-Frequency Oscillator) for modulation
- VCA (Voltage-Controlled Amplifier) for shaping volume dynamically
- ADSR Envelope Generator for expressive control
- Slew Limiter for smooth pitch and modulation transitions
All modules are routed on a single double-layer PCB, which eliminates the messy wiring and ensures clean signal paths with minimal noise. I also added pin headers for optional external patching if someone still wants modular flexibility.
Front Panel Design
To complement the PCB, I designed a custom aluminum front panel with laser-engraved labels for each section.
Every control — knobs, switches, and jacks — lines up perfectly with the board below, making assembly fast and reliable. The layout follows a logical signal flow from left to right, just like a traditional modular synth voice.
Integration
With this design, the Doepfer DIY Synth can be used as a stand-alone analog synth voice or integrated into a Eurorack system with the right power connections. No more spaghetti wiring — just plug in, patch a few CV signals, and start creating.
Sound & Performance
The sound is everything you expect from a Doepfer core: warm, analog, and responsive.
The oscillator tracks beautifully, the envelopes snap with precision, and the overall noise floor is extremely low thanks to the short internal routing. The module can produce anything from smooth basslines to glitchy modular textures.
Future Plans
I’m planning to add CV normalization options and maybe an onboard mixer for future revisions.
For now, this single-PCB version is exactly what I wanted — a clean, portable, and fully analog synthesizer voice that captures the Doepfer sound with modern convenience.
I have print spare boards if anyone likes to build — ican share the schematics private — to avoid chinese to get it :>