Applies to: iTrack Solo
The LED on the front of the iTrack Solo is designed to light when the device connects to a driver, it is not a power indicator. If you are connecting the iTrack Solo to an iOS device, the USB LED will not light up if the device is only connected to a power supply. It should light up once it is also connected to the iOS device in question via the supplied Device Link cable.
iOS devices and OS X devices (Mac computers) come with Apple's Core Audio driver installed, which the iTrack Solo is designed to utilise. As such, you will not need to install any drivers to use the iTrack Solo on these devices.
On a Windows system, you will need to first install the driver, please see this article.