Hi Harry,
Yes i noticed the voltage is on the limit, i did ask AD and they said it would be fine but I'm thinking i will drop my voltage to 15v as the DAC output uses the AD4075 and that will be okay on 15v i believe.
At the moment i have removed all the components from the B side R86,R85,R84 as well as C100 and C99
With the chip removed from the board i get the following
Pin 1 - 0v
Pin 2 - 0v
Pin 3 - 0v
Pin 4 - -18v
Pin 5 - 0v
Pin 6 - 0v
Pin 7 - 0v
Pin 8 - +18v
As soon as the chip be it a 8599 which i have tried 2 as well as 2 4075's is soldered on the board i get 15v on Pin 7. Where is this coming from? the resistors and capacitors are all removed, i have even tried grounding pins 5&6
Im a little concerned that the circuit supplied to me would need such high tolerance components to work, I'm using 5% on my resistors and 10% on my caps
Graeme