as far as i know.... dapat talaga hiwalay anf multi FX's power supply.... or isolate....
why? stompbox uses analog devices most of the time.... while multis uses programable chips.... etong chips na to eh medyo complicated pagdating sa supply..... they need to be isolated with accordance sa filtering stage, rectifier stage, at regulation...... if your planning to build an all in one PSU... with a multi fx supply with it... i suggest use two isolated transformers... what i mean is you build two independent PSUs in one box..... might cost you that much but well wort it sa space saving kung mapaguubra mo ng maganda... well thats the solution for that... and ganun ang ginawa ng karamihan dito... ang tawag dun ISOLATED POWER SUPPLY....
examples nun is yung sa VOODOO LAB ISO5 ata... basta iso....
and one thing..... analog wahs also needs to be isolated..... kundi magiingay yung.... lalo na kundi buffered