OC is VERY similar to yarns but those are all 4 channel devices.. The way I went about it it was just like this thing: https://github.com/westlicht/performer-hardware/blob/master/sequencer.pdf
8 channel 16 bit DAC (DAC8568) and same output stage as Yarns using the internal reference of the DAC (Not the power rails like AOUT, yarns uses an external reference also). I started working on the board but other things got in the way and its on hold. It was a small modular type device that was supposed to be plugged into the back of my 10hp breakout