i'am not sure how to make the best grounding for my seperate PSU.
The new complete external PSU will consist of one SMPS for mainboard and two SSR03 (5+15V) for digital/analog audioboard for my processor. The internal original SMPS will be removed out of the processor. Intern the processor all groundings are connected to chassis and chassis was connected to safety earth.
Will be possibility A or B the better way? Hope the picture clears things up.
I think your main problem here is multiple ground loops and one loop is one too many.
psu waiting on r-core transformers
better idea only to connect the chassis of the processor to mains safety ground?
Why don't you:
Remove A and B
Remove the internal ground connection on the preamp since I suspect that you already have connected the grounds on your pcb's? Connect your preamp chassis to the signal ground. Since you have approved transformers and SMPS the preamp doesn't have to be connected to protective earth.
the internal ground connection on the preamp side cannot be removed, all grounds are connected to chassis. A or B was an idea (not already done). The different grounds in my external psu are not connected because this is already done on the preamp side.
Did i understand you right i do not need to connect psu ground to protective earth? With original SMPS this was done into my preamp.