Need suggestions on efficient book shelf speakers for a Pass Labs XA3.5

@puffbojie ha! I drive Wilsons Audio Sabrina with XA30.8. Your XA30.5 is 30w into 8ohms in pure Class A at lowest distortion rated by Pass Labs. It then switches to Class A/B and delivers around 130w/ch. You know it’s in Class A/B when the needle on a bias meter starts to move. 
 

What’s the rest of your set up - source, preamp, running balanced or single ended? How could the volume be too low? Define low volume - knob position or step number relative to max setting. 

@puffbojie Benchmark DAC 2 with built in pre? I would seriously consider a good linestage to go with the XA30.5. I just sold my Benchmark DAC3 HGC that I tried as a preamp for few days (it was sold due to a DAC upgrade and not because preamp in it wasn’t up to the task).
While it was accurate, it was no match to my Pass XP-12 when it comes to dimensionality, soundstage and natural tone. Also, in my experience Pass amps sound best when run using balanced interconnects. Going from benchmark into pass balanced should result in higher gain and lower noise floor. Give it a shot.

@puffbojie not ideal especially if the source end is RCAs.
Pick up a pair of balanced Mogami Studio Gold cables from Amazon. Give it a shot and if you’re still not happy, just return them and start checking out other speakers. I have a feeling this will change things for the better though.