Pass Labs AMP’s- What is the best Pass Amp Sound for You from past 10 years

Recently acquired First Watt F7. Using with Avalon Ascendant ll in medium/small room. Incredible combination. Pre is Rowland Capri. 

I've been through three Audio Research line stages on one X350.

Every year I talk about upgrading the X350 but so far it really hasn't given me a good excuse to. And I don't really need much of an excuse. Maybe next year I'll finally get a .8.

I’ve recently added a Cary SLP 97 F1 pre for use with the XA25. The Cary is an absolute gift in musicality and I have also added a Tara Labs power cord to the XA which has truly added bass to the setup. I rarely use my XP22 pre now. 
I wonder if an Aleph 1 or 2 mono would be a nice addition???   

I've owned Aleph 3, Aleph 30, XA30.5, and for the past 5 years First Watt SIT-2, along with lots of tube and SS amps from other companies.  SIT-2 was a revelation, marrying many of the best qualities of SS and tube amps. 

I recently decided to try the SIT-3 and it just takes the beautiful voice of the SIT-2 to the next level.  More vivid, more detailed, more present with better bass control.  SIT-2 sounds more laid back by comparison.

I was so impressed with the SIT-3 I bought an XA25 a week later for another system and damned if I don't love it too.  It has a slightly drier and more neutral sound than the SIT-3 and more linear top to bottom.  Better bass control still and a little fuller/denser tone to instruments, better speed.  SIT-3 is juicier, sweeter, with wider soundstage and better sense of air and space around and between instruments.  Sometimes voices and certain instruments can sound hauntingly beautiful.

Both are just so good and having the fortune of owning both, being able to interchange them, is a joy.  I'm also happy to report that they both drive my Magnepan 1.6QR very nicely, though mine have the completely different from stock Magnestand crossovers so I don't know what the real impedance curve looks like.

The one I loved was the 250w Threshold S/500 STASIS OPTICAL BIAS II, biased up to approx 20w Class-A, nice and toasty, delicate but a brute when called for, 36 x bipolar output transistor, heaps of current.

Cheers George