Since you're in northern Europe, it would almost look mandatory to contact Christian Isenberg in Hamburg. He's the absolutely maniacal (in the good sense, that is!) distributor in Germany, who's developed and builds two phono-stages that are specifically made for Jan Allaerts (one for the MC1 and another for the MC2). He can very probably also advise you about the hum. When you meet Christian, chances are you will find him in a passionate discussion with Jan Allaerts, Simon Yorke and/or Jean-Christophe Crozel (of Lavardin).
http://www.isenbergaudio.de/Isenberg/isenberg.html
http://www.isenbergaudio.de/Isenberg/isenberg.html