Recently bought the HE1000 Stealth with a FiiO K13 R2R and finds the sound excellent, with no treble harshness and bass they especially like. A crackle when boosting EQ turned out to be missing pre-gain, fixed with a -3 dB cut.
“Recently bought the wonderful HE1k stealths and paired them with a fiio k13 r2r dac/amp. First inpressions, the sound is excellent. I did not feel any harshness in treble and I really like the overall sound , especially bass.”