Looking for a crystal clear / dynamic tube preamp

Sounds_real_audio,
Not sure where you got the impression I am looking for “A world beater tube preamp”. I am just looking for a “KISS ASS” tubed preamp... Oh my, can you say “ASS” on Audiogon? (BLUSH!) If so..., I’ve got a few others terms I would like run by my fellow audio-infected victims.

Correction: the comment "KISS ASS" should have read "KICK ASS". Mia culpa.

The ARC LS-25 was a relatively expensive preamp. At the new price I wasn't in love with the LS-25 but it is quite viable at the used price. The original LS-25 used 6922 tubes. The Mk II revision (2001) used 6H30s. So far, the 6H30 preamps I've heard haven't done it for me but I have not heard the new ARC Ref 3, The BAT VK-51SE or the Joule LA-150 so that opinion certainly isn't written in stone.
I tend to like tube preamps and amps that do not have much in the way of euphonic tubey colorations (some C-J and Cary products come to mind as too tubey) but still offer the dimensionality and "flesh" that the best tube gear provides. The preamps I've recommended strike a middle gound; not as SS sounding as some 6H30 designs but also not appreciably warmer and sweeter than life. You'll have to work out where that sonic line falls for you.
I would take a SF Line 3se or a BC 3 Despina Mk II in preference to either variant of the LS-25 but not by a huge margin. There is an upgrade path for the LS-25 through Great Northern Sound. Their Wadia mods are very good but I haven't heard the ARC mods.

Yes, the Magnum uses 6SN7 tubes. Not sure how microphonic they are compared to other tubes since my experience is limited. Certainly no more so than my current McIntosh c2200 preamp which uses 12AX7 tubes.
However, there was a noticeable improvement when I placed a Herbies Tube Dampers (@$12.) on each tube, and, used Walker SST on the tube pins which totally eliminated even the minimal tube hiss present - it became totally quiet. Made it even clearer sounding than it already was.