FirstWatt SIT-3 or Pass Labs XA25 for Avalon Indras?

"@ulul Power is not the key point, if I listen to music during the day the knob never goes beyond half of the current power amp ... ... The aim is to have magic and involvement at low volume."

Others here have already mentioned something similar to my own experience. Another .02 cents to add if it helps.

After messing around for too long over a few decades between my former 87db 4ohm and 92db 6ohm speakers, trying and owning several capable solid state and tube amps, the part about listening at "low volume" with lower current / lower power amps can be challenging to achieve for what I think you are looking for here from the sound. Sure the lower power and lower current amps will play, nice and smooth. However if that’s all you are looking for, may be good enough. Now room filling sound, that’s another thing at lower output levels. Learned this the hard way.

If you are planning to keep your existing 87db 4ohm speakers, and if filling the whole room with sound at Low listening levels, I’ve just found my traditional higher current / higher power SS amps with a little more weight to the iron and power can help. Yes, particularly at low level listening levels is what I’m getting at primarily.

Later I stopped fighting it and sold my lower efficiency 87db 4ohm speakers in order to try different lower power amplifiers again. With that said I still enjoy a tad more current/power with weighty transformers in the amps and one of those I alternate with now is only a full-time Class A 50w modified Pass amp btw. It does well for its power and size, yet when I jump to my 120w mono tube amps with double the iron, my 92.5db 6ohm speakers just sing that much more at low, medium, or high levels. Hope that helps, maybe look at something with a little more current/power/drive as others mentioned here for your Avalons. Best of Luck.

Thank you for these useful experiences. Has anyone listened to SIT3?

Between the two hands down the XA25, not even close. I have heard a few SIT amps and they sound best with higher efficiency easy to drive speakers but they were too fast paced and uneven sounding as a system. The SIT3 only has 11db gain which is extremely low and may sound anemic with typical gain preamps. Even the XA25 sounds best with higher gain preamps- e.g. 20db or so.

The SIT3 only delivers 8 watts at 8 ohms before it starts to clip, unless you have a small room, listen close to the speakers and like moderate volume listening cross that one off of your list.

I have owned the XA25 and with my speakers which have a similar impedance and sensitivity to yours the sound was excellent, one of the best sounding amps I have heard or owned.

It has almost twice the gain as the SIT3 and starts clipping at 90 watts per channel despite it's 25 watt rating.  

In addition to suggestions above, if you still have interest in Pass design, look up reviews of the SIT 4, particularly a video of Steve Guttenberg (SG), a stereo unit, due for release in mono block --twice the power. SG suggests "notably more powerful sound than specs suggest". Of course there is only one way to find out. Enjoy the search.

I own both the XA25 and SIT3 but can’t add anything meaningful to the conversation because I don’t know your speakers.  My speakers are all 8 ohm and high sensitivity and I use multiple subs so low level listening is very enjoyable.   These are quality amps when system matched properly.