why do expensive amplifiers produce a better soundstage

"In the case of expensive amplifiers (whatever the threshold for “expensive”), the power delivery is usually (but not always) less affected by speaker impedance variations with frequency and therefore the sound heard by the listener is usually more consistent with the information on the recording than with less expensive amplifiers, that presumably are less capable of delivering consistent power across all frequencies, and particularly with harder to drive speakers that present more severe impedance fluctuations, due to cost compromises in the amplifier’s power supply and other design compromises." 

Whew! One of the longest sentences I have ever read ; )

@tcutter +1 yep.. “expensive” things money could go to marketing - sales team instead of improving engineering and production line! 

@westcoastaudiophile On marketing…… and possible talk-up commission enhanced embellishments made by sales teams.

To more informed folk on here, there’s nowt so queer as hype.

Can we state that a greater expense correlates to an improved signal to noise ratio? Or expense might be part of pricier bits inside the machined metal box?

I understand that there are exceptions.

@yamaho wrote:

why do expensive amplifiers produce a better soundstage

I don't know why this is naturally assumed; they don't necessarily. On the other hand let a given amp run its speaker load actively without the interference of a passive crossover between it and the speakers (which naturally requires more amp channels for each driver section), and then you would have a more resolved, cleaner and more effortless sound altogether, which could aid the acuity of the spatial aspect. 

@russbutton wrote:

It is a physiological response to wallet depletion.

Good one.