I recently purchased one of these and it really is a world class phono stage. Over the years I've had both Pass ONO units, the CJ pr15, an earlier version Aesthetix IO, and lots of lesser units. It is by far the best sounding with the possible exception of the IO.
I was suprised to find Raytheon 5842's in after reading the claim on their website:
Its unique circuitry utilizes specially selected very low noise high trans-conductance Western Electric 417A / 5842 vacuum tubes.
When I asked them about this they said that the dash between 417A and 5842 means "or." They told me that the WE tubes are too expensive and hard to get so they use the Raytheon. In my opinion this is being deceptive since WE also stamped their tubes with 5842 and Lamm invokes the WE name with no intention of ever using the tubes.
So now I sit here and wonder if I'm missing something by not getting some real WE 417A's to try, but I don't want to spend that kind of money if it doesn't change things for the better.
Has anyone tried real Western Electric tubes in it?