Most disturbing audio experience of 2013

[mep]

Most disturbing for me was realizing how badly engineered the Pass XP-25 phono is in terms of magnetic-field isolation - virtually non-existent, with the board wrapped in simple aluminum casing (aluminum has permeability equal to air's - virtually =1). I found out the hard way that users' choices to install this unit far far away from anything else is an absolute requirement; my alternate solution will be described in the hum thread I started, soon.

How long has mu metal been around?

 

[ack]

... indeed; and even simple carbon steel might have been enough (one owner did shield with some steel variation) - see the permeability values of various metals here http://en.wikipedia.org/wiki/Permeability_(electromagnetism)