The ARC LS 17 is a very good pre but do be aware-- it does NOT sound tubey. I owned and sold one because I wanted just a touch more sugar in the sound. The LS 17 and likely by extension the 6H30 tubed LS 26, will be fairly exacting in their presentation. This is not bad-- it's great actually -- for some-- but see if it's your cup of tea.
In my experience the primary thing you gain by adding a linestage in your situation is dynamics followed by perhaps more refinement up top.
In my experience the primary thing you gain by adding a linestage in your situation is dynamics followed by perhaps more refinement up top.