Best 6NS7 Preamp for a Pass Labs XA25 amp

I agree with mboldda1

The Ultraverve never fails to amaze me.  I use mine with a vintage 5692 6sn7 military tube.  It also sounds great with the usual suspects: Tung sol round plate GT, Raytheon vt-231, Sylvania W,  Kara, the designer of the Ultraverve is very responsive to questions, upgrades, etc. She recently upgraded mine with Dueland caps. I run it through my Bryston 14bsst.  Highly recommended!

I have a Supratek Sauvignon that uses the 6SN7. Sounds really good.
I also have had a chance to listen to "The Dodd" battery preamp hooked up to my XA-25. Incredible. would have loved to had a longer listen. I think it uses a 6922. I'm going to roll a few through the Supratek in the next few months and see if I can get a little more air. 

pfeiffer - May I ask you which Dueland caps she used and did you send your unit to Kara herself to do the upgrade?  Also, how would you describe the sonic change from the original caps which I assume you were using before the upgrade. Thanks!

@gadios Can you report on the ss kit you referenced?

For people who don't know, Wayne Coburn is the designer of the pass labs preamps. I'd like to give it a shot to compare against my Don Sachs pre (I have first watt f4 mono blocks).

Just curious what it's called...