As a means to satisfy my cravings for finding cool music, I've been wearing out the needle on the old Sun stuff. I feel like the grit and intensity in those recordings is something that modern engineers have a tough time replicating, even/especially with their fancy digital equipment. However, this brings me to an interesting notion. I've always believed that one's musical tonality will travel with them, regardless of the instrument chosen to express it.
A few examples, a premier banjo player picking up an electric guitar and having the same overall feeling and emotion as with the banjo. A tap dancer who also has a wonderful singing voice. A painter who is also an incredible sculptor. The interesting thing about it is that they carry over a certain style into every avenue of life. 
My point is, it may not be the grain and lack of technology in these old recordings which makes them so fascinating and energized. It's absolutely in the style , the crafted passion of the musicians on record. I would also say that style is very difficult to fake, and is very easily detected as fake. What happened to style?