Camber - Three Pole VC Filter

An ultra-compact 10HP VC filter with bags of personality. Camber can be treated as a subtle, non-intrusive sound design tool, or something much more lively.

Overview

Camber is designed to be a fun, tactile filter with a small footprint. It’s sound is neutral enough for basic filtering without a fuss, with a much more aggressive tone available using high resonance settings in three-pole mode.

Filter Core
The core of the filter is based on a state variable topology using 2164 VCAs and 1% tolerance integrating capacitors. Resonance and feedback control is provided by the fantastic circuit design originally by Neil Johnson “Voltage Controlled 3-Pole State Variable Filter” recently made available in Sound Semiconductor documentation.

Operation
Camber is switchable between low pass and high pass responses with one pole (6dB) and three pole (18dB) flavours of each. It has full CV control of both cutoff frequency and resonance amount. The input is DC-coupled allowing LFO and CV signals to be routed through the filter. The filter will also act as a simple oscillator producing a clean sinusoidal signal with the resonance control turned *almost fully clockwise, and no signal at the audio input. Dialling in the resonance so that it is just under the point of self-oscillation allows the filter to be “Pinged” by sending gate signals to the audio input. This is useful for tuned percussion sounds and FX.

Specifications and downloads

• Intellijel 1u format
• Width 10HP
• Depth 33mm
• Power requirements ~40mA +12V/~40mA -12V
• Control voltage range 0-8V
• Impedance Input 100K / Output 1K

• Latest user manual
• Quick start guide
• Modular Grid

User Interface

Typical Response Graphs

Signal Flow Diagram

Audio Examples

Drums into Camber. Low pass 18dB slope, Resonance at 65%, CV controlled.

Joranalogue Generate 3 Oscillator into Camber 3-pole low-pass then switched to 1-pole (at 0:35). Resonance is high, sitting at the self-scillation threshold.