The entry-level question: “What other modules should I get?” The entry-level answer “more VCA’s”. Now here are other cool tools that would basically put any modular synth setup towards a further evolutionary step.
Erica Synths – Black Xfade
Hardly any modules can be found for crossfading – yes, you can crossfade between two seperate VCA’s – yes you can do it with any modulation signal and its inverted pair. But come on, it can be much easier with a dedicated module which can even keep the signal at a constant gain! Erica Synths have always been loved for these quirks (e.g. the emphasis de-emphasis circuit on the Black Quad VCA). The audio on the Black Xfade is high-quality and any “weird” or chaotic waveform can be tamed to be less clicky and more controlled.
More tips (approved and recommended by the manufacturer):
use it as a waveshaper with original vs. boosted signal.
you can also crossfade between two clock or any CV signals.
4ms Company – Shifting Inverting Signal Mingler (SISM)
It is hard to begin to talk about this module, because you have to mention at least 4 different terms. Any signal can be turned inside out – boosted up, cut into (two) half(-ves), mixed, “mirrored” .
Apart from that, the MIX SWitch (jack outputs sum of all channels with nothing plugged into their output jack),
For DIY’ers: you can find a PAD breakout header (2×4) on the PCB which can be connected to an external DIY module that enables a pre-set pad (attenuation) on each channel. Any modulation signal of yours can receive its passport to new territories in new and simultaneous forms with this module!
Other good tools people seem to forget about…
You might want to remain simplistic or regard polarizing as an enhancer of the modulation section of your system. A tool that “shifts” and turns signals “inside out”…
Yet, do not forget: polarized audio signal + feedback = new filter curves!
Steady State Fate – GND Cntrl: some users crave visual feedback and precision. I much more prefer numeral feedback than staring at visuals on a small screen. Each to its own… The SSF Gnd Cntrlmatches and attenuates / divides audio and CV signals to minute hyper-precision ranges. Ideal for live or studio!
And finally, something new: these tools are getting more and more varied each year: a new module is the AWM-3 from Vintage Synth Lab. It is an all analog, real-time, complex wave-shaping (triple wave-folder) 3-channel mixer module with added features of compression and multiple mix modes including matrix mixes.