doepfer PSU3 is mains AC
Frequency Central is mostly 12v AC - I think their new one is DC
Most others using wall or rug warts will be DC - Arturia, 4ms, befaco, tiptop etc
if it's not stated in the manual, ask the manufacturer - most have support email addresses listed on their web sites... if they don't respond, then don't buy from them
"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