Welcome Erwin !
I'm from Belgium too, la Gaume. I also hate these f*cking noisy fans and that are always too noisy whatever people say. Some even pretend that the 3 fans of a Hartke LH series are quiet when that make the sound of a jet at take off...
So back on tracks, here are some best candidates, but they are not that much as I've tried almost everything available with one 12 inches speaker (my favourite combo type) :
AER BassCube (favour the very first generation with the huge radiator that have no fan, but don't forget their later iteration that has a really dead quiet small fan which will only start when very hot).
EBS Drome 12 (the Swedish ones, not the Chinese horrors).
Gallien Kruger MB 150 S or E (there was also an MB 200 back in the day).
GR Bass Cube (the fan can be disabled).
That's all...
I also use an original EBS Taurus 240, but it's a combo equipped with 2 x 10 inches speakers (with integrated chorus and octaver).