The Feedback Cello is a new electroacoustic actuated instrument in which feedback can be induced independently on each string. Built from retro-fitted acoustic cellos, the signals from electromagnetic pickups sitting under each string are passed to a speaker built into the back of the instrument and to transducers clamped in varying places across the instrument body. Placement of acoustic and mechanical actuators on the resonant body of the cello mean that this simple analogue feedback system is capable of a wide range of complex self-resonating behaviours. This paper describes the motivations for building these instruments as both a physical extension to live coding practice and an electroacoustic augmentation of cello. The design and physical construction is outlined, and modes of performance described with reference to the first six months of performances and installations. Future developments and planned investigations are outlined.