Olivella Modular - Olivella Modular - Furia

Furia is a filter and a VCA in one module. The low-pass side is a discrete four-pole ladder inspired by the E-mu Modular 2100 LPF, built entirely from transistors — no chips in the audio path, right down to the output op amps. That gives it a thick, clearly analog character with a quite a bit of grit.

There's plenty of gain on tap. The INPUT LEVEL knob starts distorting around nine o'clock and interacts with the resonance, so you get dirt without another module in the chain. The VCA adds to that with an X10 switch that drops its input impedance, letting you push filtered sounds into overdriven, acid-y basslines.

The two sections connect in useful ways, the AMP CV input is normalled to the filter's FREQ CV, so one envelope can move cutoff and volume together — much like a low-pass gate. A curve control sets the VCA response from linear to exponential, and AMP IN mixes a second signal into the amp after the filter.
Very nice for acid lines, gnarly leads, or as a characterful filter-and-amp pairing behind a single oscillator.

Features:

• Discrete 4-pole (-24 dB/oct) ladder low-pass filter with transistor VCA
• Filter based on the E-mu Modular 2100 low-pass filter
• Fully discrete audio path — no ICs, transistor-based output op amps in both the VCF and VCA
• Filter CV input with attenuverter
• VCA CV input with attenuverter
• Pre-filter saturation via the INPUT LEVEL knob (distorts from around 9 o'clock, interacts with resonance)
• AMP CV variable response curve, linear to exponential
• X10 switch lowers VCA input impedance tenfold for distortion or pre-amplifying external sources
• AMP IN mixes a signal into the VCA after the filter
• AMP CV normalled to FREQ CV for low-pass-gate-style patching
• DC-coupled ladder filter — passes control voltages as well as audio
• Rear DIP switch for AC-coupling of inputs/outputs and re-routing the VCF → VCA normalling (series, parallel or independent)
• All CV inputs allow audio-rate modulation
• Reverse power polarity protection