I have discovered C27 is missing from the BOM; 10uF cap
also the BOM has C21 and C22 but I cannot, for the life of me, find C21 or C22 in the schematics.
Also, two of the 4 150uF caps were replaced with 33uF tantulum- diagram and BOM were inconsistent.
the other two simply are committed. They serve to filter the audio channels, and are still part of the PCB- I have yet to see if it will work without them while I wait for mine :)