@jl1ny Congrats, like we discussed, it's a great preamp. No need to worry about tube rolling...there are no vintage 6H30s out there with sonic advantages over current production unless many other tube types.
My only advise is when changing other components, go for ones that are truly balanced designs vs. just having XLR outputs...to best take advantage of the VK51SEs benefits.
When you have an impressed visitor ready to buy one too, you know where to find me.
Cheers,
Spencer