OK, at the very least, what the amps (FiiO E10K amp, FiiO E10K line out -> FiiO K6) do relative to the line out of the E10K is get rid of the dynamic impact and bass power of the Elear. The sound is very dynamic when using just the line out, while it is boringly flat and lifeless out of either of those amps. I've compared directly, switching between them within seconds.
If you have a E10K, try using the line out. BUT LOWER THE VOLUME IN YOUR OS FIRST TO ABOUT 15% AND BE SURE NOT TO USE ASIO OUTPUT (it will always be full volume, right?).