The characteristics of a synth’s sound has a lot less to do with the VCOs than the filters or VCA or the circuits between them. A properly made sawtooth or square or triangle or sine will sound the same as any other properly made waveforms. They will have the same harmonic content. The errors in the waveforms - slanted tops of square waves, sagging ramp and triangle waves and the most common error, overshoots on rising or falling edges, will contribute to the sound but they have to be fairly severe before they affect the harmonic content much. Since all makers of VCOs strive to make as perfect a waveform as possible, these errors are pretty small in most synthesizers.
Filters on the other hand have lots of differences. Phase irregularities between different stages, changes through the operating ranges, different attenuations when adding resonance, lots of stuff like that. They add MUCH more character to the sound of a synth than the VCO with standard waveforms does.
Another factor is in semi-modulars that is not present in full modulars, is the interaction between the different modules in that system. Most often the chain of modules in a semi-modular voice have been tuned to the input and output impedances and levels of the stage before and after them. This can change the sound a lot.
Basically what I am saying here is, if you want to match a synthesizers character with an older model, the place to look is not the VCOs (if they both use standard waveforms) but the VCFs instead. Unless you listen to your VCOs raw, in that case start looking at wave shapers instead.
-James
Hi.
This will probably sound stupid, but it’s bugging me so I need to ask. I have a few older synths (Arp Axxe, SH-1000, SH-2, etc) that I love using because the sound is “sharper” (more bite) than modern synths. I can’t say I am 100% sure of this but I think there is a sort of “snap” at the start of each cycle of the waveform and it gives it more of an electric or buzzy sound. Personally, I LOVE this sound and would like to have it in my Modular synth.
I’m pretty sure the slew rate mode that Moog does to the Voyager helps achieve this kind of sound to a small extent.
But it seems that eurorack oscillators have a smoother, perfected sound and I haven’t been able to find any that sound like that. I don’t have that many but it’s pretty expensive to experiment!
So… is there some way I could modify a Doepfer oscillator to get that sound It would be great if I could get a couple of A-110-2s or 110s and modify them to have this sound. Any information would be helpful (including other mods).
Thanks!
Scott