Use this song if you are doing an A/B with Preamps

I agree w the concept of evaluating a piece of gear with music you’re intimately familiar with. Listen for the transients and background artifacts and with piano, the decay of the keystrokes. But as others point out, it’s so hard to isolate sonic differences to 1 piece of equipment unless it’s on loan to you and swapped out with Everything else kept the same. Personally
I d never base an equipment decision on the replay of 1 song. 5 of different genre, well maybe, all other things being perfectly equal