The summation of the two signal can be done by addition (direct effect) or by subtraction (direct - effect) - in practice this means adding the effect signal either directly or inverted (180 degrees phase shift) to the direct signal.
In stereo operation one of the outputs carries the direct effect signal, the other one the direct-effect signal, thus achieving a very spatial and rich sounding chorus.
Alongside the familiar Rate- and Depth- controls this pedal had an added control to chose the formation of the output signal in mono/stereo-setup (more details in the technical part later).
The CE-5 was released November 1991, and the circuit differed already strongly from the original, now with added equalizer/tone control (Filter) and balance control between the dry (no effect) and wet (with effect) signals (E. The CE-5 was still based on the BBD chip, until in 2001 Boss started using surface mountable devices on the circuit board, the board being now labeled CE-5A.
In 1988 Boss moved the fabrication of their pedals from Japan to Taiwan to increase productivity, and also many of the components used in the CE-2 were changed to similar parts from other vendors - most likely cheaper ones.
Boss released the next pedal in this series in 1982, the CE-3, which was marketed as the stereo version of the CE-3.
The Chorus Ensemble CE-1 was published June 1976 and it is based on a circuit which Roland used in their JC-120 Jazz Chorus amplifiers from 1975.The sound of this unit is simply sweet - it has a soft, rich and full-bodied character that broadens and enlarges the sound beautifully.