Ok Guys like i told now the last Test with this little Amp 
Removed the AC from PCB and Connected directly to an Lab Powersupply.
±25V (Measured befor on that Amp, AC Transformer 2x 19V 2A)
Frequenzy Response: (No little Peak @ 100Hz anymore!)
THD and THD+N Differential now so much better:
before:
before:
So now i go for this Linear Regulated Powersupply for this Amp:
https://www.audiophonics.fr/en/linear-regulated-psu/lv1084-20v-5a-dual-controlled-linear-power-supply-module-p-8426.html
2x LT1083 up to 7,5A Regulator
Any Suggestion what i could do better here??? Adding Mains Filter Probably?
For the INUC and USB Hub and all QA USB devices i will use this PSU for Mains and also an big switch with 2 4mm Connector for 12V Battery Supply for in Car Measuring.
https://www.audiophonics.fr/en/diy-kits-and-boards/audiophonics-psu-s4-hp-linear-power-supply-module-dc-micrel29752-p-10435.html
Robert