What are your Eureka Moments in this Hobby?

Wow another spot on memory @1111art !  My first serious surround system consisted of Miller and Kreisel S1-Bs, a M&K sub and surrounds.  I went on to have two M & K systems.  i have probalby owned 5 of thier subs and still have three in my vacaton home.  Amazing push pull subs still hold thier own today, although the plate amplifiers would sometimes fail and the volume pots on the plate failed as well. Fortunately I can solder!  A true value in thier day though.

Musically speaking, hearing the first Zeppelin LP, Electric Ladyland, and Zappa's Uncle Meat were Eureka moments.

In terms of gear, my exposure to Magnepan Tympany speakers in the '80s was the first time I heard an audio system that was convincingly like live music--I recall an acoustic piano recording was playing.  I have no idea of what electronics were used.  I think this was at a restaurant, actually.   I've been a fan of dipole panel speakers ever since, and have settled on an upgraded pair of Apogee Duetta II speakers as the way to get both the soundstaging of tall dipoles and satisfying bass response.

Discovering Tekton speakers. 

Decades ago, coming from, or wanting to believe (because of cost) the view of “Stereo Review’s” Julian Hirsch, that all amplifiers sound the same (i.e., they're sonically indistinguishable) as long as the individual amplifiers were operating within their linear range (having low distortion, not clipping and having a flat frequency response etc.). 

However, when owning an Aragon 4004 MKII amplifier (pretty darn good Dan D'Agostino designed amp in its own right), I trialed an Audio Research VT100 amp (100 w/ch vs my Aragon's 200w/ch, but tube vs ss). 

Oh my, for the first time with the VT100, instruments sounded much more like the live ones I had the pleasure of hearing every day.  That started me on an amplifier sojourn.  I eventually settled on a Mark Levinson and later, a CAT JL1 and then, CAT JL3 and later an Atma-Sphere MA-1 (OTL) and a Pass Labs amp.

But even before I trialed the AR VT100, when demoing Apogee Stage speakers at a dealer (before I bought them), the audio store demoed them with amps that I (have now) forgot.  What I didn’t forget, was the crescendo of a symphonic piece I had brought.  Whoa, the drive and uncongestedness of the ending was something I had never heard!  But because of cost, I delayed getting into the higher end amps.

As an aside, I’ve come to believe that symphonic music provides a true test of what components are capable.  Yup, I’ve heard all of the “audiophile” vocal and intimate jazz recording etc.  And they do well displaying what a component can do.  But throw on the end of a symphonic piece (from a great recording, often like those found on Reference Recordings, or Chesky's) and assess the transition from soft passages to louder passages and as well, check-out the instrument separation and how congestion-free crescendos are reproduced for a true test of a component’s capabilities, especially amplifiers.

For me it was when I changed out the Carver amps with a pair of McIntosh MC 352 s. Driving a Martin Logan Request.  Amps mater