"I did it, it is good" bias.

Dan Ariely: Master of Human psychology of various forms

I really like Professor Dan Ariely. I read three of his books and watched every video I could find he was featured in. I highly recommend investigating his work.

The one titled “The IKEA effect" translates exactly to DIY project. If you did it yourself, you are biased!

Outside eyes will judge it for what it is, as often disproportionally far from your own opinion.

If you build an Audio Project from a KIT or online plans, you are VERY biased.

If you design your own project, it's like the kid example, you are EXTREMELY biased!

Don’t fight human nature, but be aware how other people’s brains work. Keep this in mind when reading someone’s own assessment of their DIY project or something they recently bought.

Personally, I always wait ~ six months before fully committing to something, and never sell anything unless it's been unused for at least 18 months.

If I buy a new piece of equipment or build a new prototype, I make it part of my system for six months and then, I re-introduce what I had before. By then, the honeymoon is over, and often, the initial piece had qualities I forgot. It's not rare for these initial products to "reclaim the win" and I resume my search for improvement. Whilst its a slow evaluation process, it’s the only way to truly progress and prevent your own bias from making a wrong decision

Bias can be price based too. A $2000 amplifier must sound better than a $500 amplifier, especially if you just bought it, and then try to convince yourself how good of a decision it was :)

I love to hear other people opinions about sound reproduction in general. The areas I focus and value most are often quite different from others. Comments often make me weigh in other aspects more. To me, deep and effortless bass makes or breaks a system. Regardless of how great the voices are, if the bass is boomy or has resonance, I only hear that and I certainty don’t enjoy it… period.

I'm guilty of having a strong bias on electronic designs. For technical reasons, I prefer multi-regulated balanced circuits, and my cumulative experiences tend to confirm their vast sonic superiority. However, it’s still a bias when I assume it, before actually testing it out.

I also dislike all Class D, but it’s not from a lack of trying over and over again but always in vain. A "Black Swan" could pop in at any moment. And while I’ve yet to see one, I keep the hope alive.