Short List of Amps I prefer over the Pass Labs XA25 or INT 25

Chorus, I recommend that you get your hands on a new or used Sugden A21SE class A signature single ended. I’m using it on my Tannoys and it sounds wonderful. $3250 new....30 watts into 8 ohms, 40 into 4 ohms....no bells, no whistles, just 5 line inputs, a record out, and a remote......my Tannoys are the Legacy Eaton's....

In my opinion, the question posed by the OP and the responses that followed are all presented in the absence of the central question of what speakers will be partnered with the proposed amplifiers. Without this information, most if not all the recommendations boil down to personal preferences.

IMO the First Watt amps are nothing special.  I have heard four of the upgrades so far.  I built a FW amp using better parts and point-to-point wiring that was much better in every area.  Cost me about $500 in parts, etc.

As for Luxman products (which I like BTW) I met the Luxman rep a month ago.  He was trying to tell me that EI transformers were quieter than toroidals.  That goes against anything I ever learned.  He told me after many years of research this was their findings.  So what does that mean?  Well nothing if you prefer the sound of their products.

As for the OP question, the amps that I build are what I prefer but knowing Pass Labs products the one you are referring to is an excellent amp when I had it in my system.

Happy Listening.

Two quick thoughts...

1.  @tomlhuffman is completely correct that every outcome is totally system dependent.  This issue is routinely ignored on the forum, which is to some extent the nature of the beast... but really, it's unfortunate that every person doesn't list their system along with their post (or in their associated system page).

2.  @chorus, I'd just like to note that I also was more interested in SQ than value.  Once I bought my Coincident Pure Reference Extreme speakers, I went on an amp search that involved Atmasphere M60s, Lyngdorf TDAI3400, Coincident Frankenstein 300b monoblocks, Pass Labs XA25, and DIY First Watt SIT3 and F4 monoblocks.  I originally built the F4 monoblocks as a booster amp to pair with the Coincident Frankenstein 300bs in order to improve bass performance, but ended up preferring them to all the other amps listed.  They also happened to be the cheapest.  I was happy about that, but it had no impact on my decision, however.

3.  @kalali, I totally agree, and it's a shame how often this happens on Agon.  Fortunately, at some point during the discussion it did come out that the OP has Tannoys, which is the only reason I posted about alternative Pass products.

@bigkidz Is there anyway I could get some pictures of your P-T-P version of the First Watt amp?  I've been considering a top quality part upgrade to my F4s and wouldn't mind also eliminating the circuit board either.  Would be really useful to see a template in making the transition.

I will say that building separate power supplies for each channel in the F4 made a huge difference in the sound.  Don't think I'll ever go to a shared power supply again.