Is positive reinforcement why things are sounding better?

I would say it sounds like you have made good choices… because when you don’t you will know it.

Early on I made a few bad choices… although I may not have known it on the first day. One of mine was I found out what grain was in the sound of a used preamplifier.  It took about three days after buying it to hear it… I could not unhear it. I lost a lot on that one… but I immediately had to trade in.

I always try to hedge my bets by always doing enormous amount of research and upgrading no less than 2x the investment. I don’t think I have been disappointed once I made sure I did both.

One thing is that you learn about sound and your tastes and over time will likely make different decisions. Often early choices focus on detail and slam and latter decisions are made on different less easily perceived parameters.

I would say that if you are hearing things that you were not hearing before, or even hearing things in a different way, it may not be confirmation bias.

Congratulations, you have improved your system without starving your family.

If you hear difference it can be perceived as improvement (already mentioned).

If you anticipate difference, it can result in bias to expect improvement (already mentioned).

If you hear even slight increase in gain/volume, it can be perceived as improvement (mentioned elsewhere).

What’s usually not mentioned: there’s a reason real research relies on controlled testing and sample sizes > 1.

If other folks who can’t see what’s being used (only 1 factor changed per trial) aren’t able to predict reliably, you’re probably imagining any perceived difference.

If you cannot see what’s being played and aren’t able to predict reliably, you’re definitely imagining any perceived difference.

If either of those results fail to apply (i.e., properly controlled trial results are consistently predicted), you can perhaps reject your null assumption of “no difference” between…

But most folks can’t be bothered with that level of rigor in their “testing,” feel convinced without real evidence, and profess their impressions as transferable realities.

So ignorance can be contagious bliss. And it can also get pretty expensive. 😉