serge and buchla characteristics

hi , every time i see or hear a serge or buchla system they sound different from most other systems by quite a lot and also quite similar to each other , so im wondering if any of you folks that own one can put your finger on it. is it just the basic sound or the type of modules that create that clean hollow organic sort of pinging si fi sound?

im curious as i don't want to buy either systems ( yet ) but would like to get some more euro rack modules that would have some of this character , so i guess im hoping its in the technique rather than just the inherent sound.

cheers

paul