The in your face qualities of the he-400 are pretty much completely dependent on the pads (they will still be dynamic sounding though).
The jerg pads make the HE-400 sound much more balanced and full.
However, the HE-500 probably has more potential, but like you said you'll need a better amp...
Have you ever heard the lcd2/lcd3? I would really like to compare the fully modded he-400 with the lcd2 :)
I never heard the he400 with the jerg pads..so i dont know how they sound..but i do know for me the standard he400 was not for me..i hadthem for 4 months and sold them to buy the he500 in november last year and never looked back when i by accident stumbled uponmaybe the most underappreciated and unknown amp ever..the 337 i have now..that thing makes my he500 sing!!!! I wont be selling those two soon i think... Tubes that i have are the best i could find sonically..i only need to upgrade the inside of the amp (caps internal wiring) and try the jerg mod myself..and then..heaven..
i listened to the lcd 2 rev 2 for an hour or so..I found him much darker then the he500 but the bass was much much better! They are two different kind of phones..one love one others the other..both are great phones..but then again..the lcd2 didnt sound to good on my amp..so once again..for both amps u have a golden rule..if u want the best out of any of the two..find the right amp for them..i did like the lcd on the violectric v200.. Maybe because that amp is a bit leaner and therefore pairs better with the darker lcd? Who knows..but if i had a lcd2 rev 2 i would certainly buy the violectric v200 for it..imho ofcourse.
Edited by hifimanrookie - 1/31/13 at 3:34pm