What are your go to LP's for evaluating new gear or new tubes?

Zappa Apostrophe

Some of the music being recommended could possibly be heard on YouTube.  It would at least give you an idea of the music style before you spend money on a record.

I've listened to some music that was recommended by others and I really don't care for it. Sucks if you've spent $30 on a record..

I used to listen to Zappa Apostrophe a lot back in the 80s' Fun album but I don't think of it as reference material. It does have some interesting sounds and songs, humor mixed with musical talent. Zappa was one of the first live concerts I ever went to back in 1970. Weird but fun show. Frank was unusual to say the least.

Dark Side of the Moon got a lot of play for me in the 70's. I have several copies of it. For real "oldies rock", I am more inclined to listen to Alan Parsons as reference material but Pink Floyd also did some good recordings, especially on Island when you can find them. Parsons is a recording engineer and it shows in his albums. Much like Chip Davis of Manheim Steamroller, nutty about getting it right. Many artists were perfectionists and many were not as well. It shows in their recordings.

I absolutely find things on youtube and have made decisions to buy vinyl or cd's after hearing or seeing a video. Have found a lot that way and some I'm content just to leave on youtube and have a casual listen. The Spoon Lady is kind of fun. Tons more but I get a kick out of her. First found The Civil Wars there (nice vinyl recordings), The Dead South, tons of stuff. 

https://www.youtube.com/watch?v=M-hs0FtFGP4&list=OLAK5uy_mZPAqZRHIUWeCJLjC732VZ2dZHRiDMgGQ

Check this one out.  The Hunter by Jennifer Warnes.  I've used it and James Taylor's Hourglass as reference material for lots of years.