It can be used only with USB power in the most computer environment without connecting to the adaptor.


However, as it may not operate normally in a powerless USB hub, notebook, or low power computer where the power of a USB port is unstable, an adaptor should be connected. Be sure to use an adaptor if connected to the iPad or smart device.


If USB power is used, and volume knob is over 2 o’clock direction at the maximum window volume, sound begins to crush. Thus, when using a high impedance (over about 150Ω) headphone, connect to the adaptor for use.