The Topping NX1s Headphone Amp comes in a full aluminum chassis, micro USB charge port, TOCOS potentiometer, and has a 40 hour playback time. The NX1s weights just 2.8 ounces, but features an OP+BUF structure for excellent performance. It comes with a gain switch along with a switch to add more bass. Each amp manufactured by Topping includes a multi-step process that includes testing to ensure a product of the utmost and consistent quality.

Specs:

• Shell: Aluminum
• Potentiometer: TOCOS
• Frequency response: 20 Hz–100 kHz
• Output power: 150 mW (32 ohms), 25 mW (300 ohms)
• Recommended headphone impedance: 16–300 ohms
• THD+N: < 0.0005%
• SNR: ≥ 117 dB
• Noise: < 3 uV (low gain), < 7 uV (high gain)
• Gain: 0 dB / 8.7 dB
• Bass: 0 dB / 4.0 dB
• Playback time: > 40 hrs
• Charge time: < 4 hrs at 1A
• Charging port: MicroUSB (with battery indicator)
• Power input: DC 5V / 1A (PCs USB 0.5A)
• Dimensions: 3.3 x 2.2 x 0.4 in (8.4 x 5.5 x 1 cm)
• Weight: 2.8 oz (78 g)
• Warning: Output voltage of charger should not exceed 5V