The Doepfer A-120 VCF1 is a voltage controlled lowpass filter (VCF) for the Eurorack A-100 system. A great choice for the beginner modular system builder as the filter section is one of the most important sound modifiers. The A-120 features control for frequency cut-off range which can be controlled manually or by control voltage (CV). The level control lets you tailor how much sound enters the filter and can be driven for warm harmonics or distortion tones. The resonance control determines the size of the peak at the filter cutoff frequency.