I've had my pair for several months now. After awhile an upper mid elevation began to wear on me a bit, and I went back to AKG 7XX for a few weeks. When I went back to the 400S again I realized what I like about the 7XX, very neutral, but maybe a little too much. So I became interested in improving the 400S sound in my system, reading about pads, amp/dac combos, and the Loki here on Head-Fi. I have not read this entire thread yet...is there a way to search a specific thread?
My current headphone amp/dac is the integrated ODAC/O2, using it on windows and mac systems. I'll need seperates to get a Loki in there.
So first step was to migrate from Tidal listening back to JRiver and lossless rips of a large CD collection, using the EQ function which sounds transparent to my ear. That was an amazing difference, the 400S was cooking with gas now. I did 4 curves from a wee bit warmer to full on warmer, and -1db @ 6k on each, and change balance depending on recording balance. JRiver allows volume difference adjustments for each curve which allows A-B comparisons EQ / no EQ that are more or less level balanced.
I like the comfort of the H400S stock pads, and the roll off was fixed exactly to my taste with the EQ. I did order a pair of Brainwavz angled pads and mounting rings, got the rings in OK, but did not successfully mount to the cans as yet. I gave up trying after a few minutes, plus since the pads really don't fit the rings this mod feels too kludgy to me. I think I'm going to return the Brainwavz. I suppose the Focus A pads are an obvious next try.
I see Massdrop has a Dekoni pad drop going, they appear to fit the round HiFiMans easily and be good quality...anyone using these?
And then eventually I'll try the Loki too. I may not like it as well as JRiver's 10 band EQ, but then I will be able to listen to Tidal with EQ also.