Just received my own unit: It´s a really nice toy and tool for mobile setups! Build quality and first impressions on DC-noise are absolutely positive.
Regarding the Low-Side-Switch-problem: I´ve checked the available space and as already mentioned in this thread there would be some space for a miniature relais. I think the problem of disconnecting the output pole could also be solved by some kapton tape on the PCB, a nylon-screw for fixing of the +jack and soldering a wire directly to the gold plated backside of the jack.
But:
- The power supply uses this low side switch for quick load disconnection, but the buck converter is also disabled in the off-state. The only energy that could flow over a parasitic ground connection could be the charge of the caps and the noise mentioned in the beginning of the thread.
- The current-sensing is also in the low side of the buck converter. This means, a parasitic ground connection heavily distorts current measurement and regulation. Neither the relais nor the high-side FET could improve that behaviour.
Conclusively I will use this thing on a power bank or use an isolated DC-DC in its supply. Else it´s not well suited for any lab-setup with common-ground DC supply.
Last but not least, this behaviour is even quite directly mentioned in the manual - but who the f... ever reads the manual of a power supply except in case of extreme procrastination