The Radial BigShot ABY MKII is a professional signal splitter and router designed for guitarists who need versatile amplifier switching functions. This black unit serves as a 1-input/2-output line selector, allowing for switching between two amplifiers (A or B mode) or the simultaneous operation of both amplifiers (A and B mode). The device addresses common technical challenges in dual amplifier setups with its built-in ground lift function and high-quality isolation transformer at the B output, effectively eliminating hum and noise. A 180-degree phase reverse switch ensures correct phase alignment between the amplifiers to minimize unwanted frequency cancellations. The audio path operates entirely passively without external power, allowing for permanent installation near amplifiers. External 9V DC power is only required for the LED status indicators, resulting in minimal power consumption when used with pedalboard power supplies. True bypass circuitry maintains signal integrity without tone-altering buffers between the guitar and amplifier. An additional always-active tuner output allows for the connection of tuning devices without interrupting the main signal path. Built with high-quality mechanical and audio components, this signal router delivers reliable performance for professional audio applications. The dimensions and weight specifications are optimized for both pedalboard integration and standalone amplifier setups.