Here are various useful info files from the manufacturers;
Stuff from the DAC board manufacturer;
DAC board schematic - 
CS4398 DAC2 192KHz - schematic.pdf
DAC board power inputs - 
power board connection - diagram.jpg
Toroidal power tranny connections - power transformer connection - diagram.jpg
Input selection jumpers - input select jumpers - diagram.jpg
Upsampling gen - up-sampling - diagram.jpg
Upsampling on - up-sampling YES - photo.jpg
Upsampling on - up-sampling YES - diagram.jpg
Upsampling off - up-sampling NO - photo.jpg
Upsampling off - up-sampling NO - diagram.jpg
Datasheets from Cirrus;
Receiver - CS8416_F3.pdf and errata for PLL circuit CS8416errata.pdf
Upsampler - CS8421.pdf
DAC CS4398_F1 DATASHEET.pdf
Older DAC CS4397_F1-1.pdf
