There are two big differences between the original Tremolo and our newer Tremolo2.
1) The Tremolo2 has presets, the original does not. So with the Tremolo2 you have quick access to a bunch (up to 8) of tremolo sounds that you saved.
2) The Tremolo2 has a control port, the original does not. So you can control the Tremolo2 with a variety of things, including expression pedal, external tap switches, and MIDI (requires our Empress Midibox).
The Empress Tremolo and the Empress Tremolo2 have the same audio circuitry. So they sound the same.