Isolated grounds: How necessary?

[Grand Moff Tim]

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:

Link Removed

Sorry for the rambling, and thanks for any help.

 

[monkeyfinger]

With modern effects, the chance of ground loop hum is pretty low if you use a quality filtered power supply. Honestly, you could probably power then whole thing with a one-spot. Digital stuff can get noisy when using the same power source as some analog stuff. Filter effects like wahs and phasers seem to be the worst culprit for some reason. With multiple isolated power sources you don't have a single source of failure. I recently bought a Cioks Ciokolate. I bought it because it can power a very wide number of pedals. So I don't expect to need another power supply for many years. The last power supply I used was a Voodoo Labs Pedal Power 2+. Its a great power supply but didn't have enough juice to power what I am running now. I've used it for many many years and it is still going strong. To be honest the Cioks has more outlets than I need. I am running 1-3 effects per outlet. (I am using 12 of the 16 available.) I don't need that may outlets, but it is nice to have that extra power.

 

[Grand Moff Tim]

So is that a vote for "Isolated is nice, but not purely necessary?" Particularly for small boards? Gotta pull the trigger on something here soon.

 

[GMC]

I've run a one spot with over 15 pedals before...no grounding issues. The weakest link in a ground loop is usually your bass. So if it's not shielded properly then you can get ground hum or buzzing...and no isolated grounds will cure that, only minimize it.

 

[Alien8]

You should be okay running those on a one spot daisy chain, I'm not certain if the creation labs will cause a problem - not knocking it just never tried one. Try it, the worst that will happen is that you find a bit of noise.

 

[Mosfed]

For 5 effects I would just get a one spot. Especially if you mainly use a AxeFx at home.

 

[Swimming Bird]

I use one spots with multiple daisy chains - haven't had a problem (and my PP2 + is gathering dust). Pretty sure they draw up to 1700mA.

 

[nshuman]

It's fine for 5 effects. Heck, it's been my experience that it's fine for up to 15-20 pedals (with multiple 1-Spots). After that, noise gets murky. Look at the Godlyke Powerall as well. 2A instead of 1.7A and I found them to be cleaner noise wise when you get more pedals.

 

[Crater]

So is that a vote for "Isolated is nice, but not purely necessary?"

For MOST people and pedalboard setups, that's correct. If one wants to use a positive ground pedal in their chain, then you need an isolated power supply, or at least a separate power supply for the positive ground pedal. Practically the only positive ground pedals are Germanium transistor fuzz pedals, vintage ones or clones of them, so this often doesn't apply to bass players.