Noise trouble with a device using AD1933 DAC

[Dr Zeus]

This is for car audio audio application, where I am personally using a device made by Audio Control called a DM-608. RCA analogue 6in-to-8out Digital sound processor. Should be a solid device, it wasn't cheap; but I'm finding its quite a noise maker. Hisses with no input. Hisses on my repair bench too. Hissing can be altered by way of software setting, where the AudioControl software has both input and output gain controls. Lowering the output gain has the best affect of reducing produced noise, but also consequences of inhibiting natural audio.

Output opamps are NJM4560, which some are connected to an AD1933 DAC.

So far, I see all Digital AND Analog grounds are connected including VSUPPLY, VDRIVE, VSENSE - which are all also connected to output RCA shields (All 8). Ground -CAN- be isolated from device's general power supply ground as an option, also direct connected, or through a 200-ohm resistor (3-way jumper setting), but all of the first statement not affected by the jumper.

Power supply pins are all also connected, thats Digital and Analog supply pins.

Is AD1933 a noisy device? I'm seeing noise on input pins of opamps, which some are connected to output pins of the AD1933.

AD1933 pin 1 is Right-most-bottom. Near the White little circle.

Photos attached

Thanks in advance