Where should we connect input signal ground in API Lunchbox / 51x modules?

[Tinning-Tina]

I'm building custom lunchbox for API modules.

The output ground (pin 1 of the output XLR connector) should be connected to pin 5 of the module, is that correct?

Where should we connect the input signat ground / pin 1 of the input XLR connector?

Input signal ground doesn't seem to be in the pinout.

Any help would be greatly appreciated!

 

[sahib]

No.

Pin 1 is chassis ground and is connected to the chassis/earth.

Pin 5 is analogue ground.

Pin 1, and Pin 5 go to the power supply separately and join at the chassis/earth stud point.

There is also Pin 13 which is the power ground. You may connect that to Pin 5. But I would not recommend on the PCB. Bring it separately but join to Pin 5 at the power connector.

 

[Tinning-Tina]

Awesome, thank you very much!

Doesn't connecting the signal ground with PSU ground cause hum / noise?

 

[sahib]

It does not. In contrary, this is how it is done. All the grounds are tied together at a single point to prevent so many different currents circulating in the equipment. Below is the ground scheme for our power supply.

 

[Tinning-Tina]

Ahhh perfect, it makes sense now. Thank you very much for the clarification and for the drawing, this helped a lot!