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!

I got mine and paired it with the Sony TA-ZH1ES as the preamp and then swapped the pads for some dekoni fenestrated sheep skin pads and it pretty much eliminated any issues. After those mods, these headphones sounded very heavenly. Additionally, I didn’t really feel their plasticky construction was a negative because they are so light weight, I forget I’m even wearing them at times. I didn’t think they caused much noise either.

Your views on these matches my own observation on these renew class. The biggest weakness with these headphone besides the poor man's build quality is the terrible driver that comes with it. I would advise people to test it on at least a Stax SRM-353X or something equivalent to bring out the best these has to offer. A Koss to Stax cable is required, you can either buy them or make them from the extension cable that Koss sell.

Interested in this one!

Great review as always! I've never heard electrostatic headphones so I've been quite curious about these for a while...

Can you please advice on using a ifi iPower 9V? it has 2A and the Koss energizer states 1A, will it get damaged from the iFi power supply?
Thanks!