Like you, I have found the Koss E-stats to be an enjoyable listen, especially with acoustic jazz and vocals. I upgraded mine with a Teddy Pardo power supply, achieving much the same result as you. Finally, I added a Schiit Loki into the chain for a mild EQ boost in the lower and lower-mid frequencies. Overall, a high-value, low cost system. And, for info, I found the Kimber Silver Streaks with Ultraplate connectors to mate nicely with the energizer. Thanks for the review!