Hi people there,
I'm new to the Arduino community and started to play with an Arduino board 3 weeks ago. I have been through several schematics, eventually implemented a good Midi interface, played a lot with PWM and R2R ladder DACs, and made a simple but efficient shield for the Commodore SID chip.
Just wanted to share two things here :
A "DIY" SPI 8 bit DAC worth 0,85€ using R2R ladders and a 74HC595. It has been proved to work very well and allowed 8 bit R2R DAC on my Uno without using 8 pins of the board, and reaching output rate of 330kHz, far higher than any audio rate you'd expect.
The SIDaster shield is an Arduino shield for the SID (MOS6581 and nexts) audio chips from Commodore. It has been test proven to work well with diodes and a real SID chip.
However, I'm sharing the stuff, and would be glad to gather any feedback you have.
Loving the Arduino,