S-MIX Pinout

Pinout for the S-MIX. It's used in Later Revisions to mix the Audio from the APU, the Cartridge and the Expansion Port.

             .---\/---.
      VCC -- | 01  14 | <- PREL
     PRER -> | 02  13 | <- MUTE
    IN_AR -> | 03  12 | <- IN_AL
    IN_ER -> | 04  11 | <- IN_EL
    IN_CR -> | 05  10 | <- IN_CL
      GND -- | 06  09 | -- GND
Right Out <- | 07  08 | -> Left Out
             `--------´

• PRER: Right Preset
• PREL: Left Preset
• IN_AL/R: Audio from APU
• IN_EL/R: Audio from Expansion Port
• IN_CL/R: Audio from Cartridge

Full Mixer Schematic (From PAL 1CHIP SNES):

                       || ??                                     || ??                                || ??
           +-----------||---|IN_AR                   +-----------||---|IN_ER              +-----------||---|IN_CR
           |  10K      ||                            |  200      ||                       |  200      ||
APU Right|-+-\/\/\--+               Expansion Right|-+-\/\/\--+               Cart Right|-+-\/\/\--+
                    |                                         |                                    |
                    +----|GND                                 +----|GND                            +----|GND
                    |                                         |                                    |
 APU Left|-+-\/\/\--+                Expansion Left|-+-\/\/\--+                Cart Left|-+-\/\/\--+
           |  10K      || ??                         |  200      || ??                    |  200      || ??
           +-----------||---|IN_AL                   +-----------||---|IN_EL              +-----------||---|IN_CL
                       ||                                        ||                                   ||
       +|| 33µF                 +|| 33µF
PRER|---||------|GND     PREL|---||------|GND
        ||                       ||
                 1K
            +---\/\/\------|AV Multiout Right
            |    47K                                   || 330pF
Right Out|--+---\/\/\------------------------------+---||---|GND
            |    10K                               |   ||
            +---\/\/\---+                          |
                        |                          |
                        +---|Expansion Port Mono   +---|RF Mod Mono
                 10K    |                          |
            +---\/\/\---+                          |
            |    47K                               |
 Left Out|--+---\/\/\------------------------------+
            |    1K
            +---\/\/\------|AV Multiout Left

Source

• https://videogameperfection.com/forums/topic/schematic-for-1chip-pal-snes/