Is positive reinforcement why things are sounding better?

When I bought my first tube preamp, a ARC SP-3a in 79(?) I bought maybe six different sets of tubes for it.  Each had its own sound and I settled on the a Amperex 12ax7. Now I have an SP 9-MK ll that uses 6dj8’s and I basically did the same thing and ended up using Amperex 6922’s in it.

Half the fun of this hobby is trying new things and seeing what hat they do, good or bad.

All the best.

I’d say it’s a combination of good equipment and bias. So as long as your happy, that should be all that matters.

I have alluded to this in previous posts, but will restate it here. There is a profession called Sensory Science, which deals with the problem of designing products with particular intended sensory qualities. Examples are food, beverage, and cosmetic industries. Researchers in these areas have found it necessary to differentiate between two types of subjective experience. One is the literal experience of the physical properties of products. Interestingly, those in this field have found it necessary to use trained experts for the purpose with proven levels of sensory discriminability and repeatability. The average person is not very good at this. However, these people only serve as biological test instruments for the purpose of describing the physical qualities of products. They do not render qualitative judgements about the products being evaluated.

The other type of experience is qualitative and is limited to such generic attributes as "liking" or "preference". Such judgements are provided by a sample of consumers who are like those for whom the product is intended. These people lack the sensitivity and reliability to describe physical details of products, so they aren't trusted for that. 

In the end, the descriptive data provided by "experts" are correlated with "liking" data provided by intended consumers and the physical qualities that are most correlated with liking are chosen as design criteria for manufacture. Those in the sensory industries have found this method to be the most reliable way to produce products of consistently good quality. 

My sense is that most audiophiles consider themselves to be good at describing the physical qualities of audio systems. That might be true, but in reality it is a pretty unique skill. However, most people can easily judge whether or like something or not. My point is simply that deciding whether you like a system is a good place to start. Figuring out why you like it, or what to change, is a secondary question and you might need help with that. 

Recency Bias is a real and enjoyable thing. It is tested by how long the effect lasts. Good luck!

Acoustics parameters must be improved all together and put in balance for a specific ears/brain...

If we dont learn about all acoustics aspects of sound it is easier to loose sight of one...

But sometimes we forget this because of our focus bias pick one thing that matter for us and let the other aspect aside :

Remember it's a hobby.  Don't spend more than you can afford or money you will regret spending.  I've made many "upgrades" over the years.  I would say 70% have been an improvements and the other "upgrades" I have sold over time.  I often buy used and when I resell and consider my cost often and the entertainment I've gotten, it's in range of hobby expense.  I'm a liitle surprised about one thing:  when i upgraded an amp recently I gained bass control, elimated fatigue and etchiness and gained bottomless reserve.  I lost some imaging and defintely speed and quickness. For me some upgrades have just been clearly superior, but as I've gotten better equipment the upgrading has usually resulted in more nuanced improvements.  

@immatthewj 

Confirmation biases has nothing to do with "lying to ourself" in particular or specifically

Yes, it does, obviously.

Careful, @hilde45  , you are heading down the road to crazy-town. 

Don't worry. I have enough to do in life than quibble on the internet. Those who know how to understand English will take my meaning and either agree or disagree, coherently. I just ignore those (bots?) who make random, semi-literate grunts. Saves my time.

I just ignore those (bots?) who make random, semi-literate grunts. Saves my time.

Good plan.