Tone Generator having a variable number of channels with a variable number of operating units

A tone signal generation device having a plurality of tone generation channels, comprising:

• tone generation operation means, including a predetermined number of operation channels, for tone signal computation and generating one or more tone signals by performing a specific tone generation operation employing one or more of said operation channels for one tone generation channel, thereby providing said plurality of tone generation channels;
• mode selection means for selecting one mode from among a plurality of modes including a first mode and a second mode;
• and
• channel establishing means for dividing said operation channels into plural groups in a predetermined manner in accordance with the mode selected by said mode selection means and establishing said tone generation channels as being each constituted by a respective one of the plural groups, the number of said groups being different depending upon the selected mode to change the number of tone generation channels in said tone generation operation means in accordance with the selected mode.