But there is something strange about the +5 Volt rails.
Why do they use two separate regulators instead of one larger IC ?
Was is only for economical reasons or is there a necessarity to separate the ADCs and DACs +5Volt rails ?
The 7805 manuals says: " ... If adequate heat sinking is provided, they can deliver over 1A output current ..."
I measured 165 mA for the ADCs and 283 mA for the DACs, that´s 448 mA together, should be not such a big deal for this regulator ...
The next strange thing is the AK4393 manual (page 19) says:
" ... AVDD is supplied from analog supply in system and DVDD is supplied from digital supply in system ..."
What does that mean ?
The +5 Volt rail from U6 (marked E in my picture) runs to pin 18 of the AK4393 (AVDD) and via R174 in Channel 8 to pin 2 (DVDD).
R 174 is 10 Ohm, Voltage at pin 18 is 4,99 Volt and at pin 2 4,95 Volt. Is that the difference between analog and digital supply 10 Ohm ?