Addition, I don't know why exactly Lukatschek dislike ''iron''
(core) but he stated '' I don't like iron anywhere in the signal path''
(see above). I now remember his comment on Fremer's
review of his LP s. He blamed Fremer for using SUT by
his listening tests. One can see this as one more argument
against SUT's ( see Raul) but he used more wire for the
coils to get output at an ''reasonable level'' of 3.6 mV.
That is to say that one can avoid SUT's with this kind of
output. I have no idea if SUT's can be made without iron
core . I am very fond with my Denon AU-S1 and don't
believe that this SUT uses any iron. But I also know that
''believing'' is not an strong argument.