The Nickel amplifier is designed to provide nearly-unlimited clean power for nearly every headphone in an extremely compact and portable package. All mechanical and electrical design efforts, including layout of the 4 layer SMT board, was completed in-house with full custom tooling for all parts. Nickel uses the same rugged polycarbonate featured in our IEMs. Nickel is made in the USA. The Nickel amplifier is capable of producing high levels of power. Nickel will supply 150 mW into 50 Ohms, 250 mW into 32 Ohms, and 270 mW into 16 Ohms. Nickel is stable into an 8 Ohm load making it ideal for nearly any headphone on the market. A fixed 3 dB of gain allows higher headroom than most phones and DACs can generate, but is low enough to maintain nearly the full dynamic range of volume from any source. The Nickel amplifier uses a two-stage power supply system. A dedicated battery charger is used to keep the 220 mAh battery charged and conditioned. The battery feeds a dedicated dual-voltage converter which generates dedicated ±5V analog power rails. With this topology USB switching noise is virtually eliminated and the listening experience is not compromised, even when charging the battery. The Nickel amplifier includes our patent-pending SmartSwitch™ system. Nickel has no on/off switch. Rather, Nickel uses its internal MCU to sense the presence of the input and output connectors. Only when both connectors are occupied will Nickel turn itself on. Once turned on, battery level is constantly displayed on the integrated LED light pipe and will change from green to yellow to red as the battery charge drops. Turning off Nickel is as easy as simply unplugging either the source or the headphones.