The CS-15 is one of the more sophisticated analogue synths, but also one of the less known synths. In many aspects it can be considered as a single voice of the CS-80. But to be honest: in the original some important features are missing to reach the big brother. But nevertheless this is one of the more astonishing synths in my collection.
I did a few modifications, which you my find in the links below.
- Yamaha_CS-15_Servicemanual.pdf, the complete service manual; but the schematic in this scan is distributed over severeal pages
- Yamaha_CS-15_Schematic.png, the schematic as a single file. I merged this from the different pages of the service manual and added the connections between the various pcbs, so the schematic can be read as a single plan.
- Yamaha-CS-15_CV-Input-Modification.jpg, a very simple modification of the socket board, which provides a connection for the CV inputs and Gate inputs so you need only one cable for each input type to control both voices. If you connect cables to both inputs, the voices can be controlled separately.
- separate outputs of both voices for stereo usage - not yet described
- make it a CS80? - not yet described
- MIDI interface from old crow - not yet described