Aune B1 portable headphone amplifier with discrete class A output stage updated with lower output impedance, more IEM-friendly Low Gain, and reduced channel imbalance. SPECIFICATIONS Recommended Impedance: 16 - 300 Ohm Output Impedance: 3 Ohm Typ THD+n: <0.0008% @ 1kHz, 600 Ohm, -0dB SNR...