Work in progress.
The background noise is terrible with the current solution when i power more than 1 voice card. I assume it's because of the multiple ground reference.
I'm waiting for a RT-65b power supply and hope it will fix the problem.
I'm currently working on a layout using 4*4 illuminated encoders, see some of my other threads. If possible I will integrate the shift registers and displays on the same board (half the PCB cost). I'm just trialling an idea for encoder acceleration at the moment.