Maple is a STM32 ARM Cortex-M3 processor based development system that is compatible to standard Arduino shields. Using Maple board is really handy when more processing power is needed like for simple Audio effects. In this project there is a real-time audio processing implemented with help of guitar effect shield. Maple board gives a maximum 11.8 bit resolution to do real time 20kHz sampling which is quite enough to do awesome stuff with signals.
The actual shield contains input and output low-pass filters and variable gain amplifier. So connect input to guitar and output to headphones or further amplifier and enjoy the play.