Dave Smith goes Modular: $179 Curtis Filter Module

I’m not a modular user, just thought it might interest the crowd:


I think the price is ok, considering the module type and brand.

Or maybe I had low expectations regarding the price thinking that they would slap a 100 usd “branding extra” on it.

Wether one likes the particular filter type is another issue altogether!

I guess it comes down to the quality of the filter, though i’ve never been a great fan of Curtis stuff…

Considering the number of cool and unusual Eurorack filters out there, this seems kinda blah, in a white bread with the crusts cut off sort of way.

Nicely said !

To those words I say: “classic”

There is more than enough “classic”, what i call noisy compromise with more or less character :wink:
Curtis is for me in the league “less”…

Some of my favorite synths like SH-101, Syrinx, Chroma (Polaris), Oberheim polys, DSI stuff and old Sequential gear use Curtis, heck I even have this awesome dual stereo 3379 thing in my big-ass “5U”/MIDIbox modular. That said, I’m not that keen on it in Yurp-rack format.

The reason the CEM stuff was/is great in poly synths is that it is very whitebread with little variance. That does not great modular stuff make. I wouldn’t write it off without a good listen, but the odds of me going for it are stacked against it.

I wouldn’t call the Curtis filters neutral. Their resonance is kind of “bulgy” and feels awkward at high values (I believe it’s a matter of signal levels - it can grow way too loud on top of the signal). With no resonance they sound fairly close to the theoretical behaviour.

SH-101’s filter is not Curtis (IR3109) - Roland used CEMs only for oscillators. The SH/Juno filters just have the perfect resonance behaviour to my tastes (in terms of roundness/purity, and in terms of level of the “ringing” with respect to the original signal level). This balance is achieved by level limiting circuitry external to the IR3109 - there’s certainly no magic in this IC itself. This is the same balance I have strived to achieve in Ripples.

Yeah, sorry about not being that clear on the CEM and Rolands. It was mostly a CEM3340 VCO tryst for the SH-101 and its MC-202 sibling and then we find them in some Jupiters and MKS-80. Then there’s the whole discussion on Prophet 5 with SSM chips versus Prophet 5 with CEMs. But, overall there’s stuff labelled CEM in some of the best loved synths out there so I’m feeling a bit odd about the opinion some have that Curtis is less than good.

The resonance volume compensation or rather the lack thereof is interesting in the Curtis designs. You can solve stuff with Kirchoff but at the end of the day you still have to breadboard something and do lab work. Then it turns out strange anyway.

That’s what I like about Ripples, there’s no ugly surprises, it just sounds classically sweet. Then it’s like that every possible odd or characteristic filter out there already exist in some Euro form or another, stuff like the Wasp filter, Korgasmatron, LPGs, Bionic Lesters, Arp, the Moog ladder, TB-303,…

The Curtis filters tend to suffer from factory calibration in my experience. I have an odd synth that uses CEMs that sounds great. I love the oscillators, but the filter starts to self oscillate at 50 percent resonance. There is no way to change that because the thing self-calibrates on start-up. Now, I actually like that, but that is very unusual. Not to mention the same synth also has snappy SSM envelop chips.

Theres nothing specially bad about the new curtis chips in DSI Machines. And theres nothing specially good in there. For my taste they are like the VW Golf of filters, designed to the total average taste so everybody can somehow like them - besides us individualist bastards :wink:

You can nowhere compare the DSI Chips with the good old CEM3379, these are totally different beasts, its a bit like with the classic Waldorf Synths and the Pussy Galore Type of Sound generating Devices they sell today.

Like the Golf, hate the DSI filter.