KX77FREE's KX-MODULAD is a pretty cool FREE analog modular synth for Windows.
Features:
Full parameters controls to make Additive Waveforms with no aliasing.
Full 32 bit High Quality Waveforms.
Same quality for all clock frequencies: 44.1 khz to 192 khz.
independent WaveTracer engine: KxWaveTracer.exe.
Stereo routing.
All modulations are pre-connected, no cables on the GUI.
3 Polyphonic EGs with for each segment: curves, velocity and Kbd controls.
1 Monophonic EG with for each segment: curves, velocity and Kbd controls.
Multiple trigger sources and sync for the EGs and the LFOs.
2 Oscillators with 2 waveforms and 2 outputs with Phase modulation and Sync.
2 independent Sub Oscillators.
2 Monophonic LFOs with 2 Rates and ASR EG.
2 Mulitmode VCFs.
Mixer with 6 sources: Noise, Vco1 1-2, Vco 2 1-2, Ring, Vco1 Width, Vco2 Width and 3 outputs: VCF1, VCF2, VCA.
Each mixer voice can be modulated by different sources.
Noise Generator with an EQ.
Sample&Hold.
Ring Modulator.
6 host sync clocks.
2 Midi inputs.
1 Distortion.
2 Delays with sync, multimode filter and modulation oscillator with sync.
Full NRPN implementation: More 500 parameters.
128 presets
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"Analog Modular Synthesizer with an Additive Synthesis WaveTracer to build high quality waveforms. 128 KX presets (70's and 80's...)" Via