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Knowledge base of ~80+ markdown files across 14 domains (00-13), Logseq graph, hardware design files (KiCAD), infrastructure configs, and talas-wiki static site. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> |
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Talas One — Open Hardware Condenser Microphone
A large-diaphragm condenser microphone designed for professional audio recording. Fully open hardware: schematics, PCB layouts, BOM, and assembly documentation published under CERN-OHL-W-2.0.
Overview
Talas One is a dual-PCB condenser microphone based on the Alice OPA circuit topology by DJJules:
- Preamp board — OPA1642 low-noise operational amplifier, balanced XLR output
- Hex inverter board — TC4584BF-based voltage multiplier providing bias voltage for the condenser capsule
The dual-PCB architecture means if one component fails, you replace that component — not the whole microphone.
Project Status
Prototype assembled — debugging in progress.
Both PCBs have been fabricated (PCBWay) and hand-assembled with SMD and through-hole components. The prototype does not produce audio yet — first-revision debugging is underway. This is documented openly as part of the design process.
The hex inverter KiCAD project in this repository is a partial reconstruction. The complete design files from the fabricated board are being recovered and will be uploaded shortly. The fabricated board photos and gerber files are included.
Repository Structure
hardware/
preamp/ # OPA1642 preamp — complete KiCAD project
hex-inverter/ # Hex inverter PSU — KiCAD project (WIP, see note above)
components/ # Custom KiCAD symbols and footprints
gerbers/ # Production files (as sent to PCBWay)
bom/ # Bill of materials with sourcing links
docs/
assembly-guide.md # Step-by-step build instructions (in progress)
photos/ # Prototype and PCB photos
LICENSE # CERN-OHL-W-2.0
Photos
| Preamp PCB | Hex Inverter PCB | Assembled Mic | Body + Capsule |
|---|---|---|---|
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Circuit Design
Based on the Alice OPA topology (DJJules, published on Instructables and GroupDIY forums):
- Capsule: t.bone SC-600 large-diaphragm condenser (34mm, gold-sputtered)
- Preamp: OPA1642AIDR — ultra-low noise, low distortion JFET-input op-amp
- Bias supply: TC4584BF hex Schmitt-trigger inverter configured as charge pump, generating ~60V DC bias from 48V phantom power
- Output: Balanced, transformer-less, via standard XLR connector
Bill of Materials
See bom/ for the complete BOM with component values, part numbers, and sourcing links.
Key components:
| Component | Part | Role |
|---|---|---|
| Op-amp | OPA1642AIDR | Low-noise preamp |
| Hex inverter | TC4584BF | Bias voltage generation |
| Capsule | t.bone SC-600 | Large-diaphragm condenser |
| Resistors | MFS series (metal film) | Signal path |
| Capacitors | Nichicon / Vishay | Filtering, charge pump |
Tools Required
- Soldering station with fine tip (for SMD work)
- Stereo microscope or magnifying lamp
- Multimeter
- Oscilloscope (for debugging — recommended)
- Standard screwdrivers (body assembly)
Design Software
All electronic design files use KiCAD (open source EDA).
License
Hardware design files are licensed under CERN Open Hardware Licence Version 2 — Weakly Reciprocal (CERN-OHL-W-2.0).
See LICENSE for the full text.
Acknowledgments
- DJJules — Alice OPA circuit topology (Instructables, GroupDIY, JLI Electronics)
- DIYPerks — inspiration for the "build a studio mic for cheap" approach
- The GroupDIY and micbuilders.com communities
Author
Nikola Milovanovic — Talas Group