Just did some tube rolling with my new GG. It came with the EML 5U4G rectifier and EML 45 mesh.
The unit has only be run in for about 30h.
When I changed the tubes I switched the dac off and put the preamp on mute. I don't know if that's the right way to do it. I didn't break anything yet at least.
So here are my very preliminary findings at this stage of my life with the GG. I am sure it will change over time, but anyway here it goes.
EML45 mesh > Kron45 > National union 45.
The NU did a lot better than in my 7er previously, it did not fall that far behind anymore, actually quite enjoyable, nice tonal color and midrange, bit meshy and soapy maybe, not as clear and resolving as the eml. The Kron sounded similar to the UN. Kind of in between the other two.
The Eml has more air around the instruments, more resolution and sounds fresher, brighter, the other two more on the darker side.
The Eml could need a bit more corpus and weight, sounds a bit lean at times, depending on music.
With a fully run in GG I would expect the Eml to come out on top though.