What tube pre-amps pair well with Pass amps?

You've got a smattering of responses and I'll add mine. When looking for a pre to pair with my first watt f4, I read a lot about tubes and topologies and eventually settled on 6sn7 based units. If you want a balanced design, I'd look at atma-sphere's offerings. For single ended, I was choosing between de Havilland, Don Sachs, and supratek. I eventually ended up with the Don Sachs and it improved everything about my system performance. Didn't get to demo the competition, but from the reviews, I don't think you can go wrong with any of those choices. The 6sn7 is nicely linear and sweet. I'll probably still try out a supratek at some point...

@billtro Ama-sphere (unsurprisingly) makes preamps that conform. I presume that Pass does as well. Unsure unfortunately about other brands, perhaps some others will know of some options...

@scothurwitz Thanks for posting that. My mistake actually just occurred to me yesterday and I was going to hop on to correct the error. Always great to make a mistake like that while correcting someone else's. Much appreciated. And apologies to Kent and Wayne for the mix-up too.

I'll just note that the aric audio preamps are also 6sn7 based. I'd love to hear one, as every review is very positive (and I agree with many of his well-advertised design options).

@keithr Pass labs most certainly does build active pres: https://www.passlabs.com/product_tags/line-preamps/

The xp20 is capable of 10db of gain.

And technically Kent English is primarily in charge of designing the company's award winning preamps.

Pass Labs whether due to technological or marketing reasons promotes their “super symmetry” as a selling point. This might be best used in balanced mode. Some of the Pass Labs amps have a somewhat low input impedance.  If wanting to use tubes, I suggest considering the Atmasphere and Sonic Frontiers pres.

@unsound If you're curious, here's an article where Nelson explains what the term actually means... https://www.passdiy.com/project/articles/super-symmetric-amplification