AMSynths AM8109SE JP-8 Filters ()
The Roland Jupiter-8 filter sweep in a 14 HP Eurorack module.
Overview
Most Jupiter-8 filter clones either miss the mark or cost a fortune. The AMSynths AM8109SE JP-8 FILTERS is a dedicated replication of the low pass and high pass filters from the Jupiter-8 and Jupiter-4, built as a Eurorack module that fits in even the most crowded skiff. It has no wood panels or oversized knobs. It's all about tone.
It's built around the same OTA (Operational Transconductance Amplifier) design Roland first used in the Jupiter-4 back in 1980. The low pass filter is the main event: 24dB/octave with Q compensation, just like the original. That gives a smooth resonance rise without harshness. AMSynths also included the 6dB high pass filter, which lets you gently shape the bottom end with the same vintage character.
This is a refined version of a design that first surfaced in 2010, now updated with modern components, including high-quality capacitors in the signal path. The module is 35 mm deep, so it's skiff-friendly, and the front panel is black anodised 2mm. It ships with M3 mounting screws, washers, and a standard Doepfer power cable.
Owners report a sound that's immediately familiar: warm, smooth, and deeply musical. The frequency control glides, and the resonance builds gradually, peaking just before self-oscillation in the default configuration. If you want it to howl, there's a PCB trimmer on the back to enable self-oscillation. That suits purists who want the full original behavior, and tinkerers who want more. The 2-pole mode offers a gentler slope and a silkier character, while the 4-pole delivers the classic, decisive cutoff of 1980s polysynths.
Specifications
| Manufacturer | AMSynths |
| Product Code | AM8109SE |
| Dimensions | 14 HP wide, 35 mm deep |
| Weight | 300g |
| Front panel | black anodised 2mm front panel |
| Filter types | 24dB Low Pass and 6dB High Pass Filters |
| Filter design | OTA design |
| Filter features | Q compensation |
Key Features
Slide Pots and Smart Layout
One of the most noticeable upgrades from the original 2010 design is the use of vertical slide potentiometers for cutoff frequency and resonance on the low pass filter. They give precise, intuitive control that's easy to tweak mid-performance. The MOD, ENV, and KYBD CV level controls are also sliders. The high pass filter's cutoff is adjusted with a rotary pot and an original Boss-style colored knob.
All controls are front-panel mounted. Five 3.5mm jacks sit at the base for two audio inputs, three CV inputs (MOD, ENV, KYBD), and one audio output. There's an additional audio output at the top right, handy for patching without cable clutter. The slide switches for selecting between 2-pole and 4-pole modes, and for inverting the envelope CV, are small but positive in action. They're not the kind to flip accidentally, but they're easy to adjust when needed.
Authentic Circuitry, Modern Build
The module uses the AS3109 OTA chip for the low pass filter, the same type used in the original Jupiter-8, and the AS662 chip for the high pass filter. The OTA-based design has inherent non-linearities and soft saturation. That's what gives the filter its "living" quality, one that digital filters often lack.
The design includes Q compensation, a refinement Roland added between the Jupiter-4 and Jupiter-8 to keep resonance consistent across the frequency range. Without it, filters tend to lose level as resonance increases. With it, the resonance swells evenly, which makes it more musical and predictable. Simpler clones skip this.
The circuit is faithful, but the build is modern. High-quality capacitors in the signal path help preserve clarity and longevity, and the 35 mm depth makes it compatible with shallow cases, handy for desktop or travel setups.
Flexible Filter Modes
You can switch between 2-pole (12dB/octave) and 4-pole (24dB/octave) low pass modes. In 2-pole mode, the filter rolls off more gradually, giving a softer, more open sound that suits vintage-style strings or gentle sweeps. It's less aggressive, more "silky," as one reviewer put it. In 4-pole you get the full Jupiter-8 character: punchy, present, and capable of dramatic, resonant peaks.
The high pass filter is less flashy. It provides a 6dB/octave roll-off of low frequencies, letting you gently remove mud or tighten up a mix without the phase issues of a high-cut EQ. It's not a surgical tool. It has the same warm, rounded response as the low pass side.
Collectibility & Value
The AMSynths AM8109SE JP-8 FILTERS is currently in production and available new, with a market price listed at $176. Some European retailers list it around €170 or £150, but the $176 figure from ModularGrid is the most consistently cited. It's reasonably priced for what it offers, especially compared to full Jupiter-8 restorations or boutique filter modules with similar specs.
There is no data on common failures or maintenance requirements, and current draw specifications (mA for +12V, -12V, 5V) are not available in the fact sheet. However, the module’s use of standard Doepfer power connectivity suggests compatibility with most Eurorack power systems. As it’s still in production, secondhand pricing and long-term collectibility trends aren’t well established — but for players chasing that 1980s Roland sound in modular form, it’s already considered a solid, no-nonsense choice.
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