AOUT redesign

NorthernLightX
By NorthernLightX in Design Concepts,
Hello everybody, Lately I am busy with how I will connect external filters and stuff to the MB6582. I have a stash of MAX525 chips and want to use them, and these DACs perform slightly better than those of the the AOUT_NG. For my purpose I would need the bipolar option, which by default is not on the Original AOUT board. I began designing an add-on board for the bipolar option, but soon found out that there is no easy solution of interfacing anything to the AOUT board. :wacko: I also found out that the Original AOUT board could be split. This is useful when interfacing it with MB6582; this way every core gets 4 analog output channels, 2 for each SID, for example for Cutoff and Resonance. You need 1 AOUT module per core, and if that module has the Original amount of 8 channels there is a big chance you are under-using the module, an idea I didn't like. To work around this this a trace-cut was proposed. I only have one AOUT board yet and cutting it up would yield me a board for only 2 Cores, so I would need to have another one made just to cut it up later. :unsure: All changes summed up I came to the conclusion that it would be probably just as easy to redesign the original AOUT board to include the proposed trace cut and the bipolar option. I did that and even went a little bit further by also including an option to chain the second part to the first with a few jumpers (thereby undoing the cut), so with this module 8 channels for one core is still an option. I also brought all CV and Gate outputs to the edge of the board, the original module had pins all over the place. :frantics: The only downside is that it is no longer a single sided board. I have not yet tested it, and I even have a few questions before I'm going to make a prototype. First a few pictures: [edit]11-10-2012: Updated versions of these pictures have been uploaded, the current versions on my server (and pictured here) are the most recent revisions[/edit] I have also uploaded the eagle board file and the eagle schematic. :flowers: Any and all comments are welcome, especially if you see something that could be wrong. :whistle: I also need to know the resistor values of R_x and R_y with 500 Ohm trimpots. The original AOUT PDF suggests values of 10K and 2.2K, but post by Seppoman points out that these values could be wrong when running in bipolar mode. I know a little about Ohm's law, but not enough that I'm confident I'll come up with good values. Help is appreciated a lot! :thumbsup: Cheers, Alex.
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