You can switch between headphones and speakers line out on the device by double-pressing the multifunction button. This toggles between the headphone output (PO) on the front panel and the line output (LO) on the rear panel. The unit remembers the last volume setting for each output independently, so you do not need to readjust the volume every time you switch outputs.

The FiiO K11 is a headphone amplifier with USB DAC function designed primarily to improve the audio quality of headphones. It does not support microphones directly, as it primarily serves as an amplifier and DAC for audio outputs. Compared to the Sennheiser GSX 1200 PRO, the FiiO K11 offers several advantages: - DAC chipset: the K11 uses the CS43198 DAC, which is known for its high resolution and supports up to 384kHz/32-bit PCM and DSD256. - Power output: the K11 delivers up to 1400mW at a resistance of 32 ohms, making it ideal for driving hi-fi headphones. - Connectivity: It offers multiple connectivity options such as USB, optical and coaxial, supporting a wide range of devices. - Design and operation: The K11 has a modern design with a user-friendly button for operation and an LCD display. The K11 therefore offers improved audio quality and flexibility compared to older models, but no direct support for microphones.

The FiiO K11 is more than sufficient to operate both the Sennheiser HD560S and the Sennheiser HD600. - The FiiO K11 offers an output power of 1400 mW, which makes it capable of driving both in-ear earphones and over-ear headphones with ease. - The K11's three gain levels and volume curves allow it to adapt to headphones with different impedances, which is particularly useful for the Sennheiser HD600 with an impedance of 300 ohms and the HD560S with a similar impedance. - The specially developed audio circuit and power supply of the K11 ensure a pure and stable power supply, which is essential for the optimal operation of hi-fi headphones such as the Sennheiser HD560S and HD600.