a-116, a-136, a-137-1, a-137-2 are the ones I have
the maths illustrated guide is a collection of 32 self-patches for maths
this introduces patch programming of a single module (maths obviously) and will massively help in terms of how you think about patching overall - especially in terms of constructing complex functions from simple building blocks - this is a key skill for modular synthesis - which is why I always recommend maths as the first modulation source - even if you have lfos and envelope generators, mixers and attenuverters - get maths!!! there is nothing wrong with overlap of functionality, especially when it comes to modulation and utilities
matrix mixer:
mix copies of modulation sources to increase the number of modulation sources you have
feedback mixing - mix 3 inputs with an output - possibly filtering or otherwise modifying the output before mixing it back in
use to set up send/returns for effects - ie stereo signal in to 1 & 2 output of 1 & 2 to effect effect back into 3 & 4 inputs - mix 1 & 3 and 2 & 4 to outputs 3 & 4 (or similar with mono signals, more effects etc etc)
and whatever else you would use a mixer for...
the main disadvantage of the Doepfer Matrix Mixer is size (takes a lot of hp - 20!)
the main advantage of the Doefper Matrix Mixer is size (ergonomics)
Currently I have 3 matrix mixers - a pusherman, a york modular and a reverse landfill video matrix, I can see myself adding the doepfer, as well, at some point in the future!
VCAs - 2 for audio & 2 for modulation per voice - is a good starting point...
1 vca for basic note on/off
1 vca for overall volume - so you can bring the voice in/out
1 vca for modulation
1 vca for modulating the modulation
OR just 2 for modulation
not all voices will need 4 vcas, but some may need 10 - depemnding on hoow much modulation/modulation the modulation you do!
once you get into the technique of modulating modulation - you use a lot of vcas!!!!!
Veils is a great VCA - I don't have the new version but I do have 3 of the older version (I haven't counted, but I think I have over 40 vcas including those embedded in plaits, for example)
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities