Fosi Audio SK01 Headphone Amplifier & Preamplifier 2 in 1 for Headphone Earphone Power Amplifier Active speakers

 Fosi Audio SK01 Headphone Amplifier & Preamplifier 2 in 1 for Headphone Earphone, Power Amplifier, Active speakers Notice: If you choose to ship from the Brazil warehouse, Aliexpress currently does not offer the option of collecting and paying ICMS fees on behalf of the buyer. If it is found later by the tax authorities that ICMS fees need to be paid, the buyer is responsible for paying them, and the seller will not bear the responsibility. if you mind to pay 18% of the ICMS fee, please choose to ship from China, thank you for your understanding! Features:   The SK01 is a high-power headphone amplifier with tone controls (treble,middle and bass), high and low gain settings, bypass mode, and loudnessfunction. The tone control feature allows you to customize the sound to your preferences and compensate for any shortage in your headphones or audio system. The high and low gain settings are suitable for headphones with different impedance. The bypass mode provides a pure reproduction of the original sound. The loudness function allows you to immerse yourself in the world of music during quiet nights.     Highlight:  Model: SK01 Input : 3.5MM line in Output : 3.5mm Headphone, 6.35mm Headphone, 3.5MM line out Powe Supply:5V Power Input Interface: USB Type-C THD: < 0.001% @ 1kHz and 770mV SNR: ≥108dB Frequency response: 20Hz-20kHz (±0.5dB) Amp output maximum power: High Gain: RMS 2400mw/ 32Ω,                                                   Low Gain: RMS 300mw/32Ω Headphone matching impedance: 16-300Ω Size (LWH): 4.7621.69inch (1215143mm) Net Weight: 0.641b/290g  Package Include:  *1x Fosi Audio Sk01 Headphone Amp *1x 2-in-1 USB Type-A/C to Type-C Cable *1x User’s Manual QA1.What are the charging time and battery life of the SK01?It takes approximately 2-3 hours to fully charge the battery, and once charged, it can provide up to 6 hours of continuous usage at the low gain setting, with the volume control set to the middle and the tone controls turned off. Although enabling the tone controls may slightly increase battery consumption, the overall battery life is still impressive, allowing for a full day of heavy usage or a couple of days of moderate usage. Additionally, if you prefer to use the device on your desktop, you can keep it plugged into the charger continuously,   Q2：Why isn't the USB input on SK01 working?The SK01 Only supports USB powering and a 3.5mm aux input.   Q3：Can SK01 be used while charging?The SK01 runs on battery power whether or not the Type-C cable is plugged in. Keeping it plugged in for long periods may reduce battery lifespan, similar to using a phone while it’s always connected to a charger. We recommend unplugging the cable once fully charged and recharging when the battery is low.