Now you can build the SP-12/Drumulator yourself.
Get one of the kits and follow the instructions here:
The drum chip used in the SP-12 is the dsp-D8 available here.
It is also open-sourced and the code can be founds here.
BOM for the build
CN1-CN16 Thonkiconn jacks PJ301M-12
POT1-POT6 Alpha 9mm 100Kohm Lin
1. Get the PCB out
2. Solder the D1 to D25 diodes. Mind the polarity.
3. Solder the R1 to R7 resistors
4. Solder the R8, R9, R10, C1 to C3 capacitors. Mind the polarity of the black capacitors.
5. Solder IC2 and T1 transistor.
6. Solder the IDC power connector.
7. Flip the board over and solder the 16 Thonkiconn jacks
8. Solder the 6 Alpha potentiometers
9. Finaly solder the IC1 drum chip
10. Mount the panel
11. Mount the Davies knobs
12. Mount it into your rack and drum away.