MrRay SeventyThree is characterized by a series of "imperfections" introduced in order to capture, with the highest possible fidelity, the sound of a Mark I. There are mallet noises, wooden noises, metallic artifacts and changes of volume for each single note. Also, the lower notes have a particular "growl" when you hit them hard, and when you hit more keys really hard, you'll hear them "vibrating", originally due to the instability of the harp assembly inside the real instrument. You won't hear the exact same sound twice when you play it. When keys are released you'll hear the noises produced by the "dampers" which stop the vibration of the tines.
MrDonald is a virtual rotary speaker - it simulates the famous Leslie Speaker. It features adjustable tone, acceleration, minimum and maximum speed for both the bass and the treble speakers, adjustable stereo width and balance between bass and treble. It also has MIDI control and an animated GUI.