The Electromagnetically Sustained Rhodes Piano is an augmentation of the original instrument with additional control over the amplitude envelope of individual notes. Thisincludes slow attacks and infinite sustain while preservingthe familiar spectral qualities of this classic electromechanical piano. These additional parameters are controlled withaftertouch on the existing keyboard, extending standardpiano technique. Two sustain methods were investigated,driving the actuator first with a pure sine wave, and secondwith the output signal of the sensor. A special isolationmethod effectively decouples the sensors from the actuatorsand tames unruly feedback in the high-gain signal path.