Am using the Radial BigShot EFX Loop Switcher and a Boss A/B switch to switch between two guitar inputs and two amps simultaneously (18W Marshall-esque tube/ Fender Blues Junior)

On stage, I use the Boss A/B to switch between the amps (because it has an LED indicator that is useful in a live situation) and the Radial EFX to switch between guitars (each guitar plugged into the "Return" sockets in Loops 1 and 2 of the EFX and the entire ensemble then onward into the pedalboard from the BigShot's Output socket

The resulting 50/ 60 cycle hum is horrendous

I realise I should have got the BigShot's excellent AB switch instead of the EFX Loop switcher but unfortunately this is the setup I have now. I also cannot procure an isolation transformer where I am currently located

Question - if i use the ground lift on one of the loops on the EFX switcher to minimise the hum, am I risking life and limb? Any other way to do this (I do appreciate I should under no circumstance fiddle around with the ground pins on the amps)


Edit: I just realised this is an illogical sequencing....I should be using the BigShot as the A/B switch between amps and lifting one of the grounds...but the question remains, will i be risking life and limb here??
Last edited by 18WCleanBoost at Dec 14, 2015,
I've had the same problem lots of times, the only thing I found that solved it was the built in AC plug on the back of my Super Reverb, plug the other amp into that and it eliminates the ground loop that causes that horrendous hum. I used it that way Friday night, Frnder Pro Jr plugged into the Ac outlet in the Super Reverb, the only noise I had was the usual buzz when I punched up the distortion pedal.

When you set up a ground loop, you get loads of hum. I tied running two amps with an A/B switch plugging both into a power strip, hum for days. Plug 2nd amp into the Super Reverb's AC outlet, it works great.

Not sure what lifting the ground from one would do, except leave you open to a shocking experience. I wouldn't try it, I never run any amp ungrounded.
Hmmm...I wonder what this button does...
Nothing wrong with trying the ground lift switch, as it does NOT make your equipment ungrounded, it just disconnects the signal and power ground from each other.
“Ignorance more frequently begets confidence than does knowledge.”
Charles Darwin
Thanks guys, I'll give it a try

the sequence is (was) :

Two guitars => Radial EFX BigShot => pedalboard => Boss AB-2 => two amps

I guess it now has to be:

Two guitars => Boss AB-2 =>pedalboard => BigShot => amps

and let me try lifting the ground on one of the amp loops on the EFX

The trouble is the Radial's don't have an LED indicator to let you know which loop is activated but otherwise they're great