Daughter Cards: Mutator, MS-20 Filterbank

Hi Isla fam -

This is my first post on the forum, so please bear with me. I have some ideas re: daughter cards, and not sure where to post about it.

Will Isla produce all future daughter cards, or is there an avenue for 3rd party cards?

I ask because I may be interested in producing a card or two as a 3rd party. I am based in Shenzhen and have connections to chip design houses, electronics manufacturing, etc.

I also have tremendous enthusiasm for some specific filters, namely the chips from the Mutronics Mutator and OG MS-20, the “screaming” filters from the original MS-20.

What daughter cards are planned? Any classic filter cards? My vote would 100% go towards a Mutronics Mutator reissue card, and/or an OG MS-20 filterbank card.

Either or both of these filters, dual channel / unison / stereo, with envelope followers, and LFO, with trigger in from the user’s choice of S2400 voice / output, and trigger in via CV and MIDI, with MIDI CC for cutoff, resonance, ADSR, LFO depth, rate, and delay. Something like “the ultimate filterbank” on a daughter card or two.

For me, this would transform the already incredible S2400 into a truly next level device.

Thoughts? Suggestions?

I would love to hear more about Isla’s plans for whatever daughter cards Brad has in mind.

Cheers from China


@CineLenses whats your IG ? Brodie salute


Thanks for joining us over here @CineLenses. I’m the reddit mod. 3rd party is a consideration I hadn’t contemplated but as I said before I’m very interested in the SSI 2045 (or would it be the SSI 2145?) mutronic mutator filters. I’ve seen a shot of the PCB of the Mutronics and it seems to show the SSM2045.

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welcome @CineLenses

we all know they will become a great addition, i too would love an ms20 clone set, as a long time user/owner/lover of all things ms20

we wait until isla are ready and we cross our fingers - brad has said he will use 3rd party and has some cool ideas, the details who knows… it will become clear in time when they can breathe again at isla

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Hi CineLenses,

Agree about the mutator, thick smooth sounding filter - think part of it’s sound is the excellent envelope following so agree with putting that on the card. Perhaps a few flavours of overdrive before or after the filter would work too. Full control would be amazing.

Chip details for the Mutator filter are a bit sketchy on the internet. SSM 2045 seems to be the one but many say 2044, be interested to hear from someone who knows which it actually is as I have a pair of ssm2044 deopfer filters in my modular that sound close but not as good as the Mutator in my friends studio. I have a Niio which is also an incredible sounding filter.

An FET compressor card would be an amazing addition too, like a

PM’d you.


Hey there! Thanks for suggesting I join the forum btw. re: your Mutator comment, yeah man, 100% that would be my first choice for a daughter card filterbank, with the OG MS-20 filters as a close second. I have been considering making some related products based on those filters, so when I saw your comment I had to chime in. Are you making something like this already? If so, I can do something else.

The other Mutator based product I have been working on is a sort of 4 stereo channel rotary mixer + audio interface, with assignable cross fader, where the filterbank on each stereo channel is handled by resonant low pass and high pass filters based on the Mutator (and possibly switchable with the OG MS-20) filterbanks, with assignable Envelope and LFO, knob per function, MIDI CC, and possibly ADC over USBC.

I think an S2400 daughter card based on these same chips would be pretty awesome as well, thus my post here.

Your thoughts?

Peace from the far East


Hey Rich - I’ve been off of IG for more than a year due to my VPNs getting blocked frequently. I pretty much lost access to my IG account in the process and Insta has not been able to unlock it despite my verifying my ID etc. I may setup another account once I get the VPN sorted.

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Yeah man, I think that our friend @iofflight got it right over on reddit re: the “reissuable” mutator filters being the SSI 2045 2 and 4-pole. This seems to be the closest as far as I know.

Totally agree on the FET Compressor idea as well

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@gstrg @iofflight yeah guys, fyi to put the 2044 vs 2045 question to bed, here ya go


I’m certainly not making anything in that vein, I have a lot of opinions, some more informed than others (haha) but I haven’t got that particular skill set to back it up.

There is an interesting comment from Clustercord on Gearslutz regarding the Mutator “The Mutator uses 2045 (2044 filter plus a stereo VCA), but since it utilizes the filter part only and has separate VCAs… 2044 will do, but you need to buy a (nice) VCA per channel and one LFO module.”

This was a post on how to possibly recreate something like the mutator in modular form if possible.

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Yeah, I think the commenter on Gearslutz has a fair point re: the VCA on the 2045, although as we can hear from real world examples, the magic fatness of the Mutator is indeed thinned out a bit when such an arrangement based on a 2044 + other off the shelf parts are implemented. Even sticking with a truer to OG redesign based on all the original circuits, chips, etc., a truer fidelity remake will be tough without more significant reverse engineering resources than are available based on a 2044 + whatever else we can build with it. A chipset based on the 2045 and based as much as possible on the OG Mutator is, in my view, the best way to achieve the richness of sound that is the trademark and signature of that special filterbank. Check out the 2045 datasheet for more insight about the VCA questions: https://datasheetspdf.com/pdf-file/506894/ETC/SSM-2045/1

As far as third party, Brad did say early on he was open to the idea of third party support for the daughter cards… in truth the options are far and wide.

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Having got to mess with this machine for like a week now I can say that it would be so fun to get some juicy sweepable analog filters in there on the channels. Its my first hardware sampler and just feel the roule French touch flowing through me :))).

Not that the digital ones sound bad but I can easily see the GAS sparking :firecracker: .


Hey Flux, thanks for chiming in. I would love to hear more of your insights about daughter cards for the S2400, whether 3rd party or not, Mutator based filterbank or whatever else. Cheers from China

Hey Benjamin - Way back in the day I used to spin French house at parties in Minneapolis, and definitely rocked nearly every Roulé and Crydamoure record on the regular in those days. Even now I listen to a lot of French house and electro while I run and workout. For sure, that music is the main inspiration for this concept. Nowadays I am probably more of a boombap instrumentals and lofi triphop head, and get pretty geeked out listening to that sort of music processed through old school filters in more of that French Touch style. The S2400 is an incredible gift to all of us whose taste ranges from DJ Premier, Ski Beatz, J Dilla, to Massive Attack, Portishead, and French Touch like Alan Braxe, Thomas Bangalter, and DJ Falcon


I reckon the (whichever?) VCA after the SSM chip thickens the sound. Depends how hard you hit it that gives the sound of the unit, well how driven all the components are I guess but VCA drive is really important. It’s why some boxes are legends and others aren’t, perfect signal levels all the way through the unit but a bit of squash somehere to thicken the sound and give it an identity.


Mpls Roosevelt boy here - South Side. When I graduated, it was all PE, Tribe, Gang Starr, De La. Good time to be listening to music.


And those Polyfilm caps. Mmmmm Yummy!