How far is your SUT from your Phono Pre/Preamp?

@dhcod  : Why do you need an external SUT with your Lamm PS De Luxe? 58db plus the line preamplifier gain is enough for your 103R.

Now, in the other side : Have you in the past that kind of hum problem using your Lamm with out external SUT or made any analog rig change when you got the external SUT?

If you made any analog rig change the 103 is an easy to be contaminated and develops some kind of noise as " hum " if those cartridge/tonearm connectors are not tigth secured.

R.

@atmasphere  : this comes from my post: " ( an even of the SUT it self. You can rotate it for example.  ).

R.

Dear @dhcod  : The orientation/position of the cables ( an even of the SUT it self. You can rotate it for example.  ) running is something to try. Sometimes running the cables in a " weird " position makes the hum disappears. You can try with the cables you are using and that " makes " hum.

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.