The EL-8 is designed to be driven by smartphones. The Cayin N5II is significantly more powerful. Full-size headphones I've tried on the N5II: HD6XX (drives them well.) NightOwls (drives them very well.) Meze 99 Classics (drives them exceptionally well.) Fostex T-X0 (drives them... but only just) Based on the specs, your EL-8 exists somewhere between the 99C and NightOwl in drive-ability. Probably closer to the 99C. In other words, you have nothing to worry about.