Hey, TalkBassers. I find myself needing to throw together a small board for a gig coming up in two weeks, because I use a Fractal Axe-Fx 2 at home for all of my effects processing needs, but I live in South Korea and take public transportation everywhere, and the buses are just plain too crowded for me and a bass and a gigantic 2U rack case. I'm just looking to get some essentials, throw them on a Pedaltrain nano, and run into FOH at the gig, which of course means sorting out which power supply to use. Now, I've been told that getting something with isolated outs is the way to go. The problem there is, the selection of stuff that's available to me right now is... not that good, and more often than not completely overpriced. I can find A) plenty of supplies with common grounds, B) the occasional high-end isolated ground supply that costs in the neighborhood of $400 here, or C) stuff that's ideal but only available through import intermediaries, which would mean waiting for something to be shipped to them, come through customs, then be shipped on to me. I'm honestly not looking to spend $400 on a power supply for a small five pedal board, so B is out. I don't have time to wait for a something to be imported, for fear of it not arriving in time for the gig, so C is out (at least for now). That leaves me with A: Buying something with common grounds. So all that blabbering leads to the question in the thread title: How necessary is it to have a supply with isolated grounds? Will I be sure to have problems with ground loop hum/interference if I get something with common grounds? Or am I getting all worried over nothing and will most likely be fine with a common ground supply? If it makes a difference, here's the signal chain I plan on having: Korg Pitchblack Aguilar TLC Compressor Creation Audio Labs Grizzly Bass MXR M82 B.E.F. MXR M81 Bass Pre/DI Related tangent:The Grizzly has a 9v 250mA draw, and their site recommends using the "high output" section of your power supply. Would using a 9v 300mA output for that be okay? I really have no idea about this sort of thing, haha. For what it's worth, if common grounds are okay, this is the one I'm looking at here. Does it look like it'll be okay? Amsterdam Cream Monster power supply: Amsterdam Cream | MONSTER POWER Sorry for the rambling, and thanks for any help.