One shortcoming I recently addressed: the Zoxnoxious synth was only able to address 27 channels of control voltages. I doubled this to 54 channels a few weeks back. Net result is I’m able to fully populate the backplane with six voice cards.
The next problem is how to demo. I’ve zero musical talent (as exemplified by this thread!). Thank you thank you to the people putting out algorithmic composer modules! That said, if anyone has a patch that I could port to the Zoxnoxious synth, I’d be more than happy to record a demo.
A couple cool things in the works:
Autotune. I’ve been working on this for a little while. Should be able to autotune VCOs to get some pitch stability. Maybe even tune VCFs as well? I’m getting ahead of myself there
Z5524 dual VCO synth voice demo. The Z5524 is a full synth voice with two VCOs. One of the VCOs is an SSI2130, which feature through-zero FM and some other cool feature. This’ll be a fun card to play with!
Whoa, this is wild. An analog modular synth patch-able trough the vcvrack interface for total recall. Just when you think the world has run out of ideas
Full demo coming soon but here’s a sneak peek at some of the FM stuff. Just a scope shot here for now, but this is using Fundamental’s Fade with an LFO to crossfade between modulator waveforms and/or crossfade between carrier waveforms. Nothing fancy. Except it’s a friggin SSI2130 VCO and AS3394 synth-on-a-chip being driven by VCV Rack!
Tuning: something everyone who uses VCV Rack take for granted. I’m getting to that- finishing up a static autotune method for the Zoxnoxious synth. On a tune request (yes, an actual MIDI tune request, 0xF6 message!) the synth will tune all installed boards in parallel. Static tuning, creating lookup correction tables. I’ve got the 3340 VCO tuned so far. With that done it should be short order to get the other cards tuned. Beyond the VCOs, I should even be able to tune the VCFs to 1 v/octave following the same model.
I consider the tuning is “good enough”, at least it’s way better than it was previously. This is what you get with a 12 bit DAC; though I’ve got a couple things that will improve it a bit down the road. It’s analog, the drift that remains is just character!
Demo shows two VCOs with the same control voltage applied to both. Note the “F” frequency in the scope shot on each one.
Hoping this gets beyond the vaporware phase 'cause there’s some really cool features here!
That is very well justified & I’ve been considering it. Basically, prevent the user from letting the pulse go to DC? I’d like to get to that.
I’d think pulse width may be something that may only need to be calibrated at startup. My assumption being that it isn’t so temperature sensitive as exponential converters.
The Oberheim Xpander does that, there’s a small write up in the service manual on it. I’ve not seen any description of PW tuning in Sequential’s service manual’s, and they’re my usual go-to for reference examples.
I did it before the Xpander. I guess we were arch-rivals or something. Voyetra-8 was before the Xpander. Prophet 5 still had a lot of analog in it. Like even the LFOs and ADSRs were analog.
And, yes, that description from their manual is exactly what I did in the Voyetra-8.
I never had any Octave-Plateau stuff, sure looked like some cool stuff. That must have been pretty interesting, lots of new ideas popping up around then.
I used to work with an ex-Sequential guy, I mentioned Prophet 3000 and he gets all excited as that was his baby. Lots of stories about Dave Smith and the shop closing down. And a trip to Japan trying to get an ASIC layout completed for the 3000’s chips being a complete s-storm. Got a few Prophet 3000 diagnostics disks he had sitting around.
Ok, I’ve never looked at the Voyetra-8 in-depth before, and now reading the service manual… that voice card architecture is hitting very close to home. I’m only 40 years behind. I can live with that.
well, most poly synths then were kind of the same - each voice two vco, one vcf, two adsr, one or two lfo. plenty of smaller differences. Voyetra had a sub-octave on each VCO, linear FM from one to the other. But the voice architectures of the prophets, oberhiems, voyetra, were pretty similar. Of course many difference make them all sound different.
No doubt there, Jupiter to Prophet 5 to OB-8 all fall in there and have been an influence. But all those put the voices on a single physical PCB. The physical voice card arch of the Voyetra is different: functions plug into a mainboard. That’s where I’m seeing a similarity I wasn’t expecting. I guess the advancement I can add is Zoxnoxious cards can plugged be into any slots, no dedicated slots. I’m concluding either the Voyetra was way ahead of its time or I’m way behind the time. Probably both.
yes, probably both. Of course the Prophet 5 put everything on a single card (which is I think one of the reasons they broke so much). OB already had a background in the SEM, so it was probably a no-brainer for them to go with a voice on a card. Because it was (the first MIDI) rackmount, the space in side was very constrained. Very, very, very constrained. So some of the decisions on what to put on which card were because of that.
I never had any Octave-Plateau stuff, sure looked like some cool stuff. That must have been pretty interesting, lots of new ideas popping up around then.
