AMSynths AM8109SE JP-8 Filters ()
That buttery, breathing filter sweep from the Roland Jupiter-8 — now in a 14 HP Eurorack module that doesn’t need a time machine.
Overview
If you’ve ever chased that lush, organic filter character of the Roland Jupiter-8 — the one that makes pads bloom like sunrise and basslines throb with life — you know most clones either miss the mark or cost a fortune. Enter the AMSynths AM8109SE JP-8 FILTERS. This isn’t some vague approximation; it’s a dedicated replication of the actual low pass and high pass filters from the Jupiter-8 and Jupiter-4, distilled into a Eurorack module that fits in even the most crowded skiff. And while it doesn’t scream “vintage” with wood panels or oversized knobs, it speaks in the only language that matters: tone.
Built around the same OTA (Operational Transconductance Amplifier) design Roland first deployed in the Jupiter-4 back in 1980, this module captures the DNA of that era’s analog warmth. The low pass filter is the star — a 24dB/octave beast with Q compensation, just like the original, giving it that smooth resonance rise without the harshness that plagues lesser designs. But AMSynths didn’t stop there. They included the 6dB high pass filter too, which lets you gently shape the bottom end with that same vintage character. It’s not just a filter; it’s a portal.
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 — and built for today’s modular rigs. The 35 mm depth makes it skiff-friendly, and the black anodised 2mm front panel gives it a clean, professional look that won’t clash with your case aesthetic. It ships with everything you need: M3 mounting screws, washers, and a standard Doepfer power cable. No surprises, no extra shopping — just plug it in and start sculpting.
Owners report a sound that’s immediately familiar: warm, smooth, and deeply musical. The frequency control glides like silk, and the resonance builds gradually, peaking just before self-oscillation in the default configuration. That said, if you want it to howl, there’s a PCB trimmer on the back to enable self-oscillation — a nice nod to purists who want the full original behavior, and tinkerers who want more. The 2-pole mode offers a gentler slope and a silkier character, perfect for subtle shaping, while the 4-pole delivers that classic, decisive cutoff we all know from 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’re not just visually striking — they offer precise, intuitive control that’s easy to tweak mid-performance. The MOD, ENV, and KYBD CV level controls are also sliders, giving the module a cohesive, performance-ready layout. The high pass filter’s cutoff, meanwhile, is adjusted via a rotary pot with an original Boss-style colored knob — a small but charming detail that adds a touch of retro flair.
All controls are front-panel mounted, and the jacks are thoughtfully placed: five 3.5mm jacks 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 — not the kind to flip accidentally, but easy to adjust when needed.
Authentic Circuitry, Modern Build
At its core, this 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. That’s not just marketing speak; it’s a deliberate choice to preserve the sonic character. The OTA-based design, with its inherent non-linearities and soft saturation, is what gives the filter that “living” quality — it breathes, it reacts, it feels alive in a way that digital filters often don’t.
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, making it more musical and predictable. This detail alone separates the AM8109SE from simpler clones that skip the nuance.
While the circuit is faithful, the build is modern. High-quality capacitors in the signal path help preserve clarity and longevity, and the 35 mm depth ensures compatibility with shallow cases — a real win for desktop or travel setups. It’s a balance of vintage soul and contemporary practicality.
Flexible Filter Modes
The ability to switch between 2-pole (12dB/octave) and 4-pole (24dB/octave) low pass modes is more than just a technical option — it’s a tonal shift. In 2-pole mode, the filter rolls off more gradually, giving a softer, more open sound that’s great for vintage-style strings or gentle sweeps. It’s less aggressive, more “silky,” as one reviewer put it. Flip to 4-pole, and you get the full Jupiter-8 character: punchy, present, and capable of dramatic, resonant peaks. It’s the difference between a whisper and a shout — and having both in one module is a serious advantage.
The high pass filter, while less flashy, is equally important. 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’s a character tool, with 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. While some European retailers list it around €170 or £150, the $176 figure from ModularGrid is the most consistently cited. Given its niche appeal and faithful replication of a legendary circuit, 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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