This is the schematic of the Analogue Board for 40/48 inputs:
A few notes:
- Atmega32 and Atmega324 are limited to only 40 inputs.
- Atmega32 and Atmega324 are limited to only 1 Drum Map.
- VU meters for inputs 33-48 are superimposed with VU meters for inputs 16-32 on the LCD.
- I only tested it with a development board and not with my full drum kit.