Hi all, Just to clarify: Digital inputs are not needed, everything is done with analog inputs. BUT, because of low sampling rate (~200us per channel), the sample-and-hold circuit is needed. Here you have two choices: 1. complicate your life and have a true S&H with reset and those things (2 OP-AMP per channel + 1 analog switch - as minimum), or 2. have a low-pass filter (something like in my design) to iron the signal a little. I'm really not sure what will be needed in this particular case, that's why I'll try to help Thorsten to improve ADC speed somehow ;-) It will be important when you start testing fast rolls, belive me. Lastly, but not less important, a BIG THANKS to Thorsten, this time for provding me a server space for eDrum design, this will be my main site from now: http://edrum.midibox.org/ Regards, Admir.