I’ve just stumbled on a 3396 and a 3394 so I bought them just in case (you know how it goes 
).
I’m thinking i’ll just design something simple and drive it from an MBCV if there’s nothing currently in development. I was just wondering if anyone had been busy designing a synth to use these little beauties! I remember that Stryd was working on something, but that was late last year so perhap development has stalled.
So, any news ?
Heh yeh I’ve got a lot of projects on the boiler… But there are quite a few people keen on these things as you can see…
I think the best idea I’ve seen for implementing these is to base the code around the MBSID, so naturally I’m awaiting v2 before I start taking these too seriously…
Yeah, I was following all that a while back, but it’s been awful quiet since then!
I think i’ll just use this as a starting point, http://www.ori.org/~aaronc/synth/CEM3394_V2.pdf which is basically ripped from the datasheet, and hook it up to an MBCV. However, MBCV has no ADSR, so I guess i’ll probably have to use the two gate outputs and build a seperate ADSR module to power the VCO & VCA.
EDIT: Scratch that, this guy has done all the work for us! 1-chip VCA plus a 1-Chip VCO & VCF and i’m sorted!
Having done a little more research, I think I may actually be able to complete this project! The CEM3394 is completely voltage controlled, so it should integrate nicely with the MBCV. I’m going for a modular design, which means I’ll start by building the MBCV with LCD and multiple CV-outs, then build the ADSR and LFO’s into their own seperate modules.
This synth is not going to have any pre-sets or anything, it’ll be completely Knobby with patch leads for routing. Proper old-skool!
So, with that in mind, this is the feature list i’m planning for:
1x CEM3394 module (VCO, VCF and VCA)
1x 3x envelope modules (PIC Based ADSR, 3 envelopes in one module)
1x Dual LFO modules (PIC Based, as above)
1x MBCV module
At some point i’m also planning to add a CEM3396, but since this requires an actual square wave frequency input rather than a CV to control the frequency, this is proving a little harder to work out.
re. pic lfo & adsr: are you using these?
I most certainly am!!
I imagine that those one-chip solutions would allow for a complete CEM synth on one pcb of about A5 size. Originally, I was looking for a way to clone the SH-101, and apart from the sub-oscillator, this should get pretty close i’d imagine.
How’s this then! I’ve knocked up a quick and dirty layout for the CEM3394 module.
The circuit is from:http://www.ori.org/~aaronc/synth/CEM3394_V2.pdf click
I didn’t really plan it all that well, so I ran out of room for the CV inputs to pins 6, 7 and 8, but they’re just straight CV in’s pretty much, so I just added pads for external pots or whatever. I think since the whole thing comes in at 3.6 x 2.1 inches, it’s not a bad job for a dirty hack
Any thoughts or suggestions are more than welcome!
the layout looks good!
i’m jealous - i’ve been looking for a reasonably-price cem3394 for the past year 
funny, i wanted to have a closer look at the cem3394 later this year, as 6 of them are sitting in my shelf ;D
but ok, when you put it on schedule now…
when i bought them i thought of 2-chip modules, for nice 2 oscillator sounds, with external modules for envelopes and lfo - or a 6-voice synth… 8)
well, i think i´ll go for the 2-osci modules, as i plan to build several other filter and fx modules.
i guess i´ll give the cem a try next week.
best wishes,
tobias.
I’m guessing you’re not going to be using my PCB, bearing in mind that I haven’t checked it for errors just yet.
I don’t suppose you’d be able to part with one of those CEM’s would you?? I’d like to have a two voice module, i’d planned to use the CEM3396 for a little extra variety, but that’s not so easy to integrate into a modular system.
i´m going for the ori.org schem, but i´ll build it on breadboard first, then on perfboard…
when it is<working like it should, i´ll maybe go for a etched pcb… about the cem… pm…
Sweet, cheers!
When you do get it breadboarded, i’d appreciate your thoughts on how well it performs, I don’t currently have any CV equipment to test it with. I think i’m going to go for another PCB layout soon, not really happy with the first one i’ve done, but it’s all progress!