I don't have one - but maybe it would be a good idea to check what psus you are all using
someone mentioned a uZeus - which is not known for being particularly quiet
try to find someone to test it with either a Doepfer PSU3 - which are generally pretty quiet
so it might be that the rainmaker is particularly susceptible to noise on the power rails
in which case the options are simple - put up with it, get a better psu, get rid of the module
"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