BobF
ELO's 'Lucky Man' and 'Take A Pebble' were my goto stereo test tunes back in the day
I was more thinking that you would want ELP's first album for its bombastic works. It really brought the turntable up to another level.
Again, however, a lot of European bands, did much more interesting things for the LP and its abilities. I was just listening to Family in their last period and specially "It's Only a Movie" ... and there are some spectacular things in there. Along with this, one should also have The Groundhogs' Crosscut Saw (for his unreal use of guitar effects to the max ... and how!!!!) and then "Black Diamond" ... and when you hear "Live Right" ... you will know you have been ground hogged! Super fine material that sounds even better on a great stereo and turntable.
In the early 70's Eno and some German folks were playing around with a recording technique ... head something or other ... and it was really a trip, and only "trip" albums were done with it ... so things like Faust ... sounded really far out and crazy, and when you heard Guru Guru do anything from their first 4 albums ... you know that this is crazy ... is this about sound effects on the guitar or what? But it sure sounded crazy.
For that matter, the first Guru Guru's albums should also be in the list. All the way to KanGuruGuru. The earlier stuff with Ax Gernrich is totally out of this world, and it is just a shame that folks don't check out his insane guitar stuff ... a true guitar player on "acid", we could easily say, but his solo albums are also insane and crazy, so you know that the feeling is consistent on his work, even from the early days. Let me just tell you that the LSD March and Cosmic Junk and some of those things sound amazing in a big stereo (or in my examples -- a big FM station even better), but I'm not sure that some folks here can handle the guitar noise ... and might think of it as not playing at all.
But it sure made that "krautrock" stand out and then some! And the CD's still don't do this stuff justice, though I think that Amon Duul 2 could use a really big and professional remastering, because so much of their work is really out there. YETI should be on any turntable and then some!