How is the Pass Labs X150.5 at low volume?

Sounds like you are at a crossroads. I have owned Pass amps for 40 years… typically of higher wattage… but they have the same character. I have also own Audio Research equipment Preamp / Phonostage. I cannot address your question directly… but my ARC amp sounds better at low volume than my Pass amp… but it would be a real stretch to have this be applicable to your situation.

I hold Pass in really high regard… but about ten years ago I began moving closer to all ARC gear. The outcome has been incredible. While my amp is of lower power my system is sooo much more musical! When I got to all ARC my system took on a real musicality my system never had. BTW, I am using a ARC Ref CD9se for DAC… I compared with a $22K Berkeley Alpha and I thought the ARC sounded better. Anyway after forty five years of solid state I moved to a ARC tube amp and will definitely not be moving back. My system sounds great at low volumes.


You can see my system by clicking on my ID… noticed a number of similarities.

Now this is a timely post. Last Friday I went on a tour of the ARC facitlity
in Minneapolis hosted by the gentlemanly Dave Gordon. If you see a
Bat logo on a reserved parking spot and a car is parked in it you will
know if the Commissioner is in or not. 

FYI Friday is a good day to request for a tour as they are mostly all
on 4 day 10hr work week. ARC was taken private 3 years back
and for this reason I was motivated to learn more as comglomerates
tend to lose product value in my experience.

The facility is spotless and very well organized. The repair room-manned by two techs- was model of organization and that alone surprised me.
We were shown their new I-50 Integrated which ships next month.
I predict ARC will be on a fast track to even greater success soon.

I only listen at levels of 55db to 69db. So low level performance means
a lot to me. When you ask most manufacturers what factors in a speaker
or amp's build improve low level sound I seldom hear a straight forward reply.

Currently I use a Pass INT25 with Tannoys rated at 94 Sensitivity at 4 ohms. I think it does a very good job at low levels. Prior to that I used
a Cary 120 Tube Amp which provided excellent musicality but did present all the detail the Pass does. Nelson Pass believes his Amps are more "Tubey" than other SS amps. Now after seeing the new ARC 50 INT I am sorely tempted to try tubes again. Auto-Biasing and a built in clock will simplify maintenance. The Pass gear is bullet proof and musical. Both are pricey.

Does anyone have experience comparing the low level performance of 
Solid State vs Tubes?

No experience with X150.5, but low level listening with XA60.5’s we’re quite good.

on a related note… I tried PrimaLuna Evo400 pre with the XA60.5’s and it just didn’t work well… poor synergy

Somewhat similar to @audiojan I have a Evo400 pre that I tried with a Pass 150.8 and didn't really like it. I would not use it for low level listening to say the least.  My typical volume maxes out at 80 db peaks and it sounded slow, unemotional and non-dynamic. Maybe it needed higher volume levels to bring out the best but I don't listen that way. Ayre amps have a very black background that I find works perfectly for lower levels.  It's hard to explain but it's different from anything I've heard. I use an older Ayre V-5xe with the Evo400 and am currently listening at about 53.3 db (just tested using white noise and not very accurate iPhone NIOSH app) and miss very little of the music.