I think from now on i'm going to set my own rule that I don't post impressions of amps/dacs for the DJ100 until I've listened them for at least a week.
The E10 with the DJ100 has been like a roller coaster. It goes from terrible to good to amazing and then back to terrible. The E10 is supposed to measure flat, but it doesn't sound that way.
It makes the DJ100's mids more forward than it should be. It makes the DJ100 fatiguing. I think it's the lower mids. In fact, they are too forward to be enjoyable. The DJ100 should never have ultra forward mids.
The DJ100's bass with the E10 is a tad bloated. I shouldn't say bloated, but not where it should be.
It's also less clear. Believe it or not the DJ100 sounds much better from a Sansa Clip+
The issues with the E10 and DJ100 are the same with the HD-598 and E10.
The E11 actually has much closer to neutral mids. I even prefer the X-Fi Go Pro DAC ($35, for the DJ100/HD-598) to the E10.
I think there was a guy here who didn't like the 598 and DJ100 with the E10. I don't either really.
I also can't get good sound from the line out. All the impressions above were straight out of the DAC. The only way I got the E10 to sound neutral to my amp was sending the headphone out to my amp.
I'd say the E10 with the DJ100 is quite colored and not 100% how it should sound. If you want to hear how the DJ100 should REALLY sound, use the ruler flat Sansa Clip+ as a reference.
The X-Fi Go Pro DAC is close to this. So is my Realtek onboard HD (sounds like it).
I still think it sounds OK, but wouldn't suggest the E10 for the 598 or DJ100. The E11' is far better IMO. I still would say the best portable amp for the DJ100 i've heard is the Total Airhead. It doesn't change it's sound signature at all, just improves almost everything.
NOTE: The X-Fi Go Pro is also impressive for the 598 as well. It seems the amps that are great for the 598 also play well with the DJ100. Of course i'll let you guys figure out if you think they really need one. I certainly do!
EDIT: Just bought an ODAC. Hopefully it has good synergy with my DJ100, Q701 and Micro Amp.
Only kidding... or maybe not. We'll see if it REALLY sounds completely uncolored as they say. Hope so. Hopefully it's really in stock and I can get it by the end of this week! It'll be interesting to see how it compares to the E10 and HRT MSII.
BTW the dj100 is back to $80 on amazon. Same as Best Buy now. Maybe they compete a lot? There's a pair used on amazon (for an hour they say) for $40. No, it's not mine. I only have the TB. If the DJ100 ever sells for $40 new, that's just stupid of Koss to do. Maybe they can start giving them away for free next!
I'd gladly pay for a $150 version that had some sort of memory foam pads. Maybe do a
complete (no ProDJ300 please!) redesign and remove the DJ label. I wish my DJ100 looked as comfortable as the Philips Uptown. Those pads would kill the sound though I'd imagine. XB500 pads do. I'd much rather have them make an open version (it can be done) that's less portable and more comfortable. That driver is capable of being even better than it is. I didn't realize this until I made it open and also heard it with the M50 pads.