Which amp would you choose and why - Pass Labs XA-25 or First Watt F8?

I'm very interested in Nelson designs and hope to upgrade to his low watt offerings for a smaller room I have. Does anyone have experience with the Pass Labs XA-25 and First Watt F8 amps? Both are rated at 25W. What main differences do they have? Which one has better bass?

Preamp: Cary Audio SLP98
Speakers: Tannoy XT8F (91db efficient)
@ghdprentice i use the balanced out on my preamp because it goes through another set of tubes.  i  tested it with my previous amp and using balanced out sounded more spacious and 3 dimensional than using single ended out.  
I own both. The XA-25 will play a bit louder and more dynamic than the F-8. I listen to the F-8 religiously acct. it sounds more musical, sweeter & more accurate than the XA-25. Plus it is a more intimate sound. All my listening is thru LS 3/5A speakers. I own many low watt tube amps and I still listen to the F-8 above all of the these.


Problem is the OP has Tannoy speakers that dip down to 2 ohms. Your LS3/5A’s are 15 ohm speakers. This is a huge difference. I’m sure I’d prefer the sound of the F8 into your speakers over either amp into the Tannoys.
galacticmayan - I was in a similar situation owning Tannoy (Churchill’s) and intrigued to try a First Watt product. I emailed Nelson and he said:

On thing about our amplifiers, they all like the Tannoy products – not a surprise since that’s our reference standard. If you play them at reasonable levels, then the First Watt F8 would give you some of those qualities that people like in Triode amplifiers. If you tend toward neutral then the XA-25 would be an excellent fit. You can get more power easily, but I don’t think you would need it. best, np

I think 3 Easy comments are very astute. Like him I worried that the lower power at 3-4 ohms would prove to be problematic with the F8. BTW the Churchill are 94 DB efficient. Yours are 3DB less, so it’s effectively like half the power.

I’m fortunate, I have a 845, and a 211 tube based Set amps to compair with. Further, the buzz on Tannoy is they respond better when there is more power. So I opted for the XA25, glad I did, I don’t think the F8 would keep my happy (my room, sonic priorities, etc.)

Even playing large scale complex music at lower volumes, the XA plays admirably, even Nelson says the XA amp is neutral compare to the F8, to me the XA is warm enough. However at any higher volume, and given your speaker are down 3DB, I’m not convinced either is a match unless the room is real small, and, or, your volume is lower than mine.

Aside from the previously mentioned amps I’ve also got a pair of S60 Atma-Sphere amps. There is a lot of synergy with what a) 60 watts of power will do with the Tannoys, and b) using OTL tube amps. The palpability and transparency is to die for. As good as the XA is, the S60 drive the Tannoys better IMO.
For me, the XA is the right choice with the two your contemplating. All the best in your endeavours!

For those users of either amp. My DAC has a 6volt output, so I would plan to use a (quality) passive pre-amp. Is this OK?