AM8071 Snow Fall VCF

via AMSynths

"This module is a traditional diode ladder low pass filter similar to that in the EMS VCS3, Roland SH-3, System 100 and the PE Minisonic 2. The filter has a 4-pole ladder with an 18dB like response, thanks to the characteristics of diodes. A fifth pole can be switched in to give a steeper 24dB response using the Slope switch. The control voltages can be smoothed out using the Lag switch, to give a more fluid modulation.

The filter has adjustable Cutoff Frequency and Resonance, along with a resonance CV input, 2x Signal inputs and 2x Frequency Cutoff CV inputs. The panel design is a mix of rotary and slide potentiometers. The filter was developed during the heavy snowfalls across the UK in February 2010, hence the name."


via the AMSynths blog: "Back in the late Winter of 2009/2010 there were heavy snow falls in south east England for the first time in many years. During this "white out" I designed a diode ladder voltage controlled filter similar to the ones that appeared in a number of analog synths in the 1970's, and named this new module "Snow Fall". In 2009 I had already built a number of prototype 4-pole diode filters from the EMS VCS3, Roland SH-3 and the Practical Electronics Minisonic 2. I improved the designs with modern components and added a fifth pole and slew delay on the CV input. This AM8071 protptype was very sucessful and delivered a great sounding and flexible VCF.

During Summer of 2011 the prototype was worked up into a production design using the new AMSynths panel design which has a mix of rotary and slide pots, with momentary push buttons. The production units were launched on 20 September 2011 and this EuorRack module is available to purchase from AMSynths web site."