A free, open-source stereo variable-mu tube compressor plug-in modelled after the circuit topology of the classic Fairchild 670 levelling amplifier.
Available as VST3 (Windows, macOS, Linux) and AU (macOS).
| Document | Audience | Contents |
|---|---|---|
| User Guide | End users | Installation, parameters & controls, how it works, further reading |
| Building & Contributing | Developers | Build prerequisites, clone & build instructions, running tests, project structure, contributing guidelines, license |
| Tools & Scripts | Developers | phu_calibrate offline calibration tool, plot_timing.py, plot_transfer.py, install-linux-deps.sh |
Additional reference documents in docs/:
- Offline Calibration Workflow — step-by-step guide for timing and transfer measurements
- Fairchild 670 Spec Traceability — mapping from hardware specs to DSP parameters
- Performance Analysis — CPU and latency benchmarks
Install the plug-in — download the latest release from the Releases page and follow the platform instructions in the User Guide.
Build from source — see Building & Contributing. The short version:
git clone --recurse-submodules https://github.com/huberp/phu-fair-kid-67.git
cd phu-fair-kid-67
cmake --preset linux-release # or the preset for your platform
cmake --build --preset linux-buildRun the tests:
cmake -B build -DPHU_BUILD_PLUGIN=OFF
cmake --build build
cd build && ctest --output-on-failureMIT — see LICENSE for the full text.
Third-party: JUCE (dual-licensed), phu-audio-lib (see phu-audio-lib/LICENSE).