Hum/Ground Loop?

[genome]

If any of you read it, I bought a Mark V from the States, using it via a step down transformer.

Working amazingly except I've got a bit of hum from the step down affecting my signal, it sounds like a ground loop problem, at least the interference sounds exactly like an issue I had with my studio monitors that I got rid of with a ground loop isolator like this.

I was wondering how I would go about getting rid of the hum... and whether getting one like this (obviously would need to be American) -

Amazon.com: Ebtech Hum X Voltage Hum Filter: Musical Instruments

that would go in just after the step down transformer converts the voltage, or one like this

http://www.amazon.com/Ebtech-2-Channel-Hum-Eliminator-Standard/dp/B002J4PBC2

with 1/4" jacks, although I'm not sure where that goes in the chain... in between speaker and cab? :s

Any advice?

P.S Hum is much more noticable on 90w, especially on Channel 3 Extreme. Variac Power significantly reduces the hum but I'm not sure if it's a good idea to use in a live situation.

 

[gummx97]

I have the small Ebtech hum eliminator, sometimes it works, sometimes it doesn't, guess it depends on where the ground loop is. It worked for our keyboard player in some venues that we play. Tried it with my amps, didn't work. Just have to watch out for the current rating though.

What I have that works great is the electro harmonix hum eliminator. If you're willing to compromise some "coloration" of your tone versus getting rid of that hum. It works great on single coil pick ups too! I seldom gig without it, but some folks, the trade off might not be worth the "coloration" of your tone. Most of the places we play won't hear the difference between a digital distortion to a tube amp saturatoin anyway, so the trade off is ok with me. The electro harmonix will NOT fix your ground loop issue, but will get rid of the buzz. It's only a band aid anyway, not a true fix.

 

[elvis]

First, get the step-down as far away from the amp and signal cables as you can. Use an extension cord between the transformer and the amp if you have to. Those things broadcast like crazy.

Next, the HumX might help in between the transformer and amp. Might not.

The HE-2 is for isolating different pieces of AC-powered equipment. For example, if you have a rack FX box in the amp's loop, you may need an isolation transformer (HE-2) between them, both at FX send and FX return. If you are NOT using AC-powered FX, then the HE-2 will do nothing.

If you have multiple AC-powered pieces of equipment, they should all be plugged into the same power source. Ideally, they would all be powered from the step-down. If that's not possible, they should at least plug into the same AC main as the step-down.