Easy to design one to alter sound, yes. Or, when one is driven beyond its design limits. Other than that, well designed amps, withing their design limits are transparent.
Speakers are an important link in the chain but if the signal that needs to be amplified is not carried out correctly then it pretty much does not matter!
Lots of ifs, no?
Some rec/amps come off sounding harsh and analytical with other artifacts.
Like which ones? Certainly not well designed, modern ones.
As an example I did a demo of two recievers...a Denon AVR-3806 and Yamaha RX-V2600 and to me the Denon sounded better.
Well, that is a very subjective analysis, isn't it? Better. I bet, it wasn't a level matched comparison, let alone a DBT protocol?
Of course this is my opinion and I do understand that all of this is subjective.
Yes, and most certainly. Oh, it was most likely biased as well, no?
What I'm looking for is a certain sweetness that may border on warm with the ability to accurately present a decent soundstage.
You are looking for this in the wrong component.