TheGuitarist said:
Any ideas for a trim pot for the output?
Also just wondering what the optional caps are for.
Optional caps are from the THAT1646 data sheet. They add common-mode rejection to the output, you can leave them out and just put a jumper in place of the two caps.
Here is the description from the datasheet, edited for content.
"The outputs are DC coupled to the output connector, so this dc will appear directly
at the output of the system. The output common-mode offset of a 1646 may
be reduced by adding capacitors in the feedback loop. These capacitors ac-couple the common-mode feedback loop.
This changes the loop operation from servoing the common-mode output current at audio frequencies to
servoing the common-mode output voltage to 0 at
DC. This results in much lower common-mode output
offset voltage, as indicated in the specifications
section. These capacitors are typically high quality
non-polarized electrolytic capacitors."
And here is the horses mouth:
http://www.thatcorp.com/datashts/1600data.pdf
The cost of the caps is very minimal and I would suggest leaving them in.
As for a trim pot someone with abit more smarts might be able to answer that question. But a good place to start is to check out the original schematic and then do a search to see if anything comes up.
-Casey