AM8109SE JP-8 FIlters
14 HP | AM8109SE JP-8 Filters | User Manual (PDF) | ModularGrid | You Tube
OVERVIEW This module is replication of the Low Pass and High Pass Filters from the legendary Roland Jupiter 8. This is an OTA design that Roland first used in the Jupiter 4 in 1980, and then added Q compensation for the Jupiter 8.
DESCRIPTION This is a warm sounding filter with smooth frequency control and a resonance that gradually increases up to self oscillation - a sound very reminiscent of the early 1980's. The original Jupiter 8 filter did not self oscillate because it could distort, but we have trimmed the filter so it does just go into self oscillation. You may need to back off the level of resonance if you do get some distortion.
The difference between 2 and 4-pole modes is subtle, 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 Q compensation ensures the audio signal is retained as the resonance increases, rather than dipping down.
This module uses the AS3109 OTA chip in the low pass filter and the AS662 is the high pass filter and resonance circuit. The original design has been updated to use modern components with high quality capacitors in the signal path and filter core.
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 a Roland 100M control knob.
CONNECTIONS There are five 3.5mm jack sockets at the base of the black powder coated 2mm thick front panel .
- Two audio inputs
- Three control voltage inputs
- Audio output (at the top right of the module)
The slope of the filter can be switched between 2 and 4 poles using a small slide switch, and the envelope CV signal can be inverted using a second slide switch.
The module comes with a set of M3 mounting screws and washers, and a standard Doepfer power cable.
PRODUCT STATUS: PRODUCTION
