Perplexed re: FBT 12ma loud hum

[mesaboog]

Edit, nevermind. Just needed to flip the grnd lift switch. d'oh!


WTH...

I am having some issues with my FBT 12ma. When I hook it up to my Axe-FX, perfect, quiet as a mouse, no hum or noise. But when I hook it up to my GT-10, I get a very loud hum. It goes away if I disconnect it from the GT-10 output. It is just when I plug into the GT-10. I tried different power outlets, checking for shorts and cannot isolate why the problem is occurring. BTW, settings on GT-10 are output: line/phones plugging the 12ma to left/mono output jack.

I then proceeded to test with my QSC K12 using same outlets & cable and no hum or noise.

Any ideas on what is causing this? Is it bad cables? They work fine with the K12. A polarity issue perhaps?

Weird!

PS: I know, the obvious answer is, "just don't plug it into the GT-10" :lol: , but I would really like to figure out what is going on here.

TIA,

Scott

 

[bluffalo]

As an extra to the ground lift issue, is there any harm in leaving it on all the time?

should i turn it off unless i do get hum?

 

[mesaboog]

I wouldn't turn it on unless you get hum (problems with ground loops).