It could be a number of things. The first thing I do in the high end is to try to listen the that piece of equipment. Expensive doesn’t make it the best. I look at multiple magazine reviews and blog reviews. I also look at the audio forums to see what owners are saying about it along with looking at it myself and listening to it. I grade it using my ear. I look for soundstage width and depth, high, lows, Mids and transparency. I listen for the size of the images. I listen to decay and layering to determine if it stands up to being listed among the best. Overall is it natural and musical. For example the best solid state gear I’ve heard is soulutions. It does all this!
