No preamp in system

Glad to hear you are getting used to it. Likely getting your preamp will be a real treat when returned. 

Good question you pose, of perspective and time. Until about twenty five years ago, I would say my perception was pretty relative. What sounded good, was based on what I heard. There were systems that sounded better... typically based how many details, how much bass, the width and depth of the soundstage. But I think my perception over time could be influenced by exposure and time.  

Then I went out to hear what real music sounded like. Specifically to develop an absolute measure... yardstick. For over twenty years I steeped myself in live acoustic music specifically develop an absolute measure against which to judge my system and system choices. 

I will say that my perception will vary a little... but during that time I also assembled my system to sound like the real thing... so that the absolute is reinforced. So, while I am sure my perception of "good sounding" varies a little... probably not a lot.

I’m pretty sure lots of folks simply wonder around in solution space just comparing one system versus another and in that case lots of drift is likely... I think. 

Just a stab at it. 

There are many ways to sound “good”. You never know until you try. 

Everything is relative.

@mrdecibel 

Hi!  I hope all is going well with you too.  
To answer your question: Without the preamp most everything sounds very good, but is missing something. That something is the high frequencies and, to an extent, soundstaging.  And, on some things I think it actually sounds a little better that way. With most things though it lacks a certain presence and excitement.

I agree with @ghdprentice that live music should be your benchmark. Acoustic instruments and voices are the touchstone. I don't really compare components to each other but rather listen for how "real" it sounds in my system. A lot of gear can sound impressive but over time seem artificial in some way. 

When I make changes I use music with singers I've heard live. I have an enduring sense of how their voice expressed emotion and I listen for that. 

I do experience getting "used to" a certain sound and liking it, but that's because it corresponds to my expectations for sounding real. If it doesn't sound that way, I don't get used to it, I get annoyed by it.