SMAKN X5 PCM2706 + CS4344 + Dual TDA1308 Parallel Output headphone amp board Programme: PCM2706 + CS4344 + Dual TDA1308 Plate size: 65 * 68MM (excluding terminals). it can driver 16-120 ohm headphones Supply voltage: 5 V (USB powered) Distortion: THD + N: &lt;0.008% (RL = 55 Euro)