Diy Audio mixer grounding help.

Hi all.
I recently built a 5 channel audio mixer. Inputs are all unbalanced. It has Left & right output jacks on the rear.
All jack sockets are steel Switchcraft types.
Unit has an internal transformer power supply with mains safety earth tied to the chassis.
My question is, will it be OK to connect the input &output socket grounds directly to the chassis or will I need to isolate all the sockets from the steel chassis?
To be honest, I have already mounted them directly without any audible issues. Im just curious about the proper way of doing this and the theory behind it. The output of the mixer is connected to my audio power amp and speakers. Any help appreciated!

If you have no issues, then that's perfectly fine - but normally you wouldn't mount them so they ground to a metal chassis, as you're then grounding them twice - unless you leave the screen on the connecting cable disconnected at one end.

But if it works, no worries.