I’ve started building filters again! As you’ll know if you’ve read this blog, I’m a huge fan of filters (who isn’t?). I had planned to build a few more and I’ve acquired PCBs for a couple that are waiting in the backlog, but this was an unexpected addition!
I’d spoken to a nice guy called Jens about some lightpipes for a build I have in my backlog and when he sent them, in the box was a mystery PCB and a handful of ICs and other components. A quick google later, I realised that this was a board for the AMS AM8109 filter – a Jupiter 8 LPF clone. The components were the “hard to find” parts kit that AMS supply, including some vintage op amps. I spoke to Jens and he told me this was a gift! Huge thanks Jens, you absolute legend!
I checked my spares box and found that I had everything I needed for the build already, aside from the Roland IR3109 IC, which is pretty much unobtainium.
I made a start on the build, while I tried to track down the IR3109.
AMS make a panel for the module, but it’s 14hp. I thought that, if the build worked out, I’d like to use it in my live case and logically it would replace the ST Modular Franz filter. There’s nothing wrong with Franz, I just had a feeling this would be better! So, as Franz is 10hp, I designed a panel layout that fit into 10hp.
I wired up the panel and connected the board. In the meantime, I’d managed to track down a vintage IR3109 from an old Roland synth.
I slotted it in, gave it a test and calibrated it. It sounds amazing. Exactly like the Jupiter filter because that’s basically exactly what it is!
Slots very nicely into my “tribute” filter section along with the MS-20, Moog and Wasp filters.