Interested to hear your thoughts on what cards would be of most value to you.
Personally, I’m leaning to SEM as the first, followed by analogue percussion and quad OPL3 FM.
Love the idea of an Oberheim SEM Four Voice in a desktop format. Also the TX inspired FM style engines (which I think is sorely missing on the market) and of course the analog percussion (Which could be played via MIDI on an actual electronic drum kit for that authentic Simmons type feel). The idea of having all these in a single unit is just mouth watering.
SDS-3 and SY-1 together.
Some fresh funky sound like the KORG Trident, as there is nothing like that on the market at the moment
A dual or quad SID expansion card would be amazing!
Definitely Jupiter 8 for me! There is no affordable Jupiter 8 analog poly that I can see: a vintage Jupiter 8 $25k+, Ise-Nin $4k, Roland Boutique JP-08 uses ACB, Roland Jupiter X, Xm uses Zencore. I have a Studio Electronics Code 8 that can accept their Juno/Jupiter voice filter boards, but they don’t really sound like the Jupiter, as they are just slightly tweaked ARP filters. So please make a Jupiter 8 card!
Seconding Brad’s choices. SEM and a decent FM synth would be fantastic. Drums would be great as well, so long as the sound holds up!!
Totally in for FM and analog percussion… Especially because the S2400 can be used to sample and grit things up. Dream team!
…I’d love something for a PPG/Microwave/ESQ/Mirage voice. Gritty ass waveforms through an analog filter.
Will we be able to choose the 2/4 cards that come with the preorder?
What’s the point of the percussion card exactly?
Is there a sequencer to lay drums down on?
External sequencing? One card for some nice analog drums would be pretty great, especially if we can pan them across at stereo output (one channel for mastering drums is pretty rough but 2 channels is more bearable).
Unless there was an on-board sequencer percussion card would be my last choice but I see it is a popular pick 
To each their own, if it has an excellent kick drum that alone would probably be worth it for me doing live dance-ish music. That’s the beauty of the Caladan, being able to customize it as needed. I already am hoping to use the multitimbrality for percussive sounds.
Wouldn’t the soundfont thing suffice for a drum machine.
I think that’s the beauty of being able to have interchangeable sound cards. If it’s not something you don’t think you’d want, then don’t get one. For the people that do want one, like myself, it’ll be great.
So I’m just trying to wrap my mind around this. If we preorder with the 4 cards - does that leave you with 4 slots? How many card slots are we expecting cards like FM or SEM to take up?
Yeah. Think of it like a platform with the soundfont engine built in, and then you have 8 slots that you can put in different voice cards. You can order dig with two or four of those filled with voices derived from the Futuresonus Parva (the basis for the idea, similar to how the Emu SP1200 was the basis for the idea of the S2400). So if you order it with two voices, you’ll have six open. Four, you have four open. And of course, we’ll be able to swap them in as we please when new ones are released or for special purposes.
I agree, it would dope to layer 909’s and 707’s over samples in the 2400
Regarding the potential TB303 card, I really hope it’s opened up a little bit… A little closer to the Devilfish/Behringer TD3 “modded out” idea than the classic.
Maybe a “traditional/enhanced” menu option!
You can already do that! Especially since the 707 is digital anyways 
… You just have to use samples and multiple tracks. I’d be surprised if anyone can tell the difference between a real 808 or 909 and good sample of it, which are freely available.