I do not believe the preamp section goes through the tubes in the Lampi. The Volume Control/preamp is the only thing on the Golden Gate I can fault. It isn't the sound. It is the implementation. My DAC has a USB, a TOSlink, a Coaxial Digital and a line in preamp. The DAC has 4 input settings:
1 Non DSD Digital
3 Line Level in
As far as I can tell, AUX is not hooked up to anything.
The Non-DSD input has a separate toggle button to cycle through three inputs, USB, a TOSlink, and coaxial digital. The issue for me is that I cannot hit one button to get to my DVD player. I have to hit 1, then hit the toggle button two times to get from USB to the coaxial digital. Makes using my harmony remote more difficult and makes using the DAC as a preamp untenable for my wife. It is the main reason that the Concert Fidelity remains (and will get upgraded or maybe replaced) as that is simpler to use (despite not having remote input select).