AMSynths released AM8109SE, a replication of the Low Pass and High Pass Filters from the legendary Roland Jupiter 8 and 4. This is a 2 and 4 pole OTA design that Roland first used in the Jupiter 4 in 1980, replacing a discrete version of the filter which took up more PCB space.
This is a warm sounding filter with smooth frequency control and a resonance that gradually increases up to full resonance, just before self oscillation, a sound very reminiscent of the early 1980’s. The original Jupiter 8 filter did not self oscillate, and we have retained this configuration. However the customer can set the filter to self oscillate by adjusting a PCB trimmer on the rear of the module.
The difference between 2 and 4-pole modes is not dramatic, with the 2-pole mode providing a more gradual cutoff slope and silky sound. The high pass filter provides a gradual cutoff of low frequencies.
The AM8109SE is a new version of the 2010 AMSynths design, with slide potentiometers and a skiff friendly module depth of 35mm.
This module is an accurate reproduction of the Jupiter 8 low pass voltage controlled filter, using the AS3109 OTA chip in the filter core, as well as the high pass filter that uses an AS662 chip. The design has been updated to use modern components with high quality capacitors in the signal path. It delivers a very warm and smooth sound.
There are front panel sliders for adjusting the Cutoff Frequency and Resonance of the low pass filter, and level control of 3x control voltages (MOD, ENV and KYBD) and 2x audio signal inputs. The high pass cutoff frequency is adjusted using a rotary potentiometer with an original Boss coloured control knob.
More info here: AMSynths | AM8109SE