I’m gob smacked. What were you’re aha moments?

@Imnop, What prompted you to replace your Oppo UDP-205? We have (had) very similar systems. I have UDP-205, integrated (Pass Labs instead of Anthem) and ML Montis.  My main reason for getting the Oppo was the combination of transport and dac w/balanced outputs.  What are you using for a dac now?  To get on topic, my biggest and first "aha" moment occurred in high school early 70's.  I was looking to get some cheap department store all in one.  Guys I worked with hooked me up instead with AR-XA table, Kenwood integrated and Advents.  Hooked from then on.  The next was getting Infinity IRS Gamma.  Would not have sold them except for reliability issues.

I have several occasions; replacing my PS Audio Directstream DAC with Lampizator Golden Gate Balance, replacing GG Balanced with Lampizator Pacific Balance.

Replacing my Sonus Faber Toy Tower with Audiokinesis JM 2.0 + Space Generator.

Replacing my Auralic Aries with LDM servers.

It's a very long and enjoyable audio journey. :)

I was a resident physician at Thomas Jefferson University Hospital in Philadelphia, occasionally hanging out at Chestnut Hill Audio - one day Jack Rubinson (for all you Philly 'Philes - here's a shout out to Jack for all he did for all of us back in the day) has Quad ESL-63s out ---  Gob Smacked!! I moonlighted for 3 months, bought the demo pair, later added Gradient Subs (Gob Smacked again), sold them, missed them, eventually bought the Quad ESL-2905's because, well, you know, once you listen to Quads, nothing else will do....

Gob smacked at the results?
That's an easy one.
I was gob smacked by my beta qobuz 24 x192 on roon

My first post!! 1979 I was a sophomore in high school and had finally saved up my money from summer work to buy a pair of dahlquist dq-10’s. I loved them but they weren’t ‘aha’ because all music had been like that for me including listening to Drive my Car by the Beatles in 1971 on a rigged up Bogen receiver. Now cut to about three years ago at a friends who has every piece of equipment on the planet including Shindo et al that I’d never heard of. I had also stopped listening to music seriously for many years even though being a working soundtrack composer. At my friend’s house he put on Ella and Louis record through Tannoy Glenair 15. It was like hearing the music performed live. It haunted me and has since brought me back into the world of hifi after listening to music in my car only or on a Bluetooth speaker in my home. Now to create that experience again or at least something really good.