Watts! How many do we need?

OP,

‘The difference in sound quality between my ARC Ref 160s with 70 wpc and 140 wpc is topology… one configuration is ultra linear and one is triode (70 wpc). What sounds better to me is the more natural - musical sound of the triode mode… what I am not hearing is any difference in dynamics caused by the drop in power. 

@jfmusic, I’d often seen stereo amps displaying wildly different readings when fed mono signals. While it’s very true that the fault could lobe elsewhere, it’s doubt it is not more often than not that the meters are at fault. When queried about the meters, and when not being evasive just about every manufacturer has admitted that inclusion of meters was because they looked cool, and shouldn’t be relied on for critical use.

@macg19 

I have the C7ES-XD Harbeths 

That's a very nice amp for those speakers, congrats. Fellow Harbeth owner - I'm seeing/hearing similar results. I think the "low" sensitivity of Harbeth's isn't that relevant with well-matched, high-current SS power which is exactly what you have based on Paul's video (able to double power from 8 to 4 ohms).  

Even if our meters are not perfectly calibrated, there is no doubt in my mind that they are a very good indication that the amp is barely breathing, and having virtually unlimited headroom is a really good thing. Enjoy it!