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

When I got rid of my Preamp and dac and got a direct stream dac/ preamp from PS audio. It was like holy crap what the F just happened. How can one piece of equipment make such a difference?

My B&W 802N speakers finally sounded perfect. Silky smooth highs and mids with plenty of base that was lacking previously. 

Switching from NAD M51 Dac (very good) to an Audio Note 3.1. A week later I changed out the Bryston 1b pre for a Audio Note M3 line pre.

Just another level I guess. 

@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....