Doepfer Dark Energy II is a fully analog monophonic synthesizer in a very compact yet sturdy desktop module. In addition to a sawtooth wave-producing VCO, Dark Energy II features a versatile filter section with low-pass, notch, high-pass, and bandpass modes. The lower row of the instrument also includes a handful of 3.5 mm connectors for signal modulation, such as VCO F, PW, VCF F, VCA, and Gate.