Filter 8

An analogue voltage controlled filter in 12 HP, built on the classic OTA-style four-pole cascaded lowpass. Each of its four stages has an output of its own, and mixing them gives further responses, all available at the same time.

Key features

• Four lowpass outputs, one per pole, each with its own character, and an LED at every output
• Pole mixing: one-pole highpass, band boost and notch, phase shifter and four-pole bandpass
• Self-oscillates into an eight-phase sine VCO, tracking over at least five octaves; at low frequency, an eight-output slew modifier or an eight-phase LFO
• Exponential and linear FM at the same time, the linear input with an AC switch
• Hold input and switch freeze the outputs, by hand or under gate control
• A dedicated ping input turns it into a percussion voice