Power amp humming noise???

[mcdj0nt]

I am running a pod hd500 into a rocktron velocity 300. Then the 300 into a cab. The rocktron power amp operates at 8 ohms and I have tried this setup with two different cabs, a Marshall vs412 and a peavey 4x12 (can't remember peavey model) both set ups have resulted in a very loud humming noise when I turn the volume of my power amp up. My power amp was purchased used and I did notice the fan does not come on when I turn the power amp on. Is this a problem with the amp? My pod? My cables? Please help as I am very new to rack set ups.

 

[psycle_1]

Unplug the HD500 from the power amp and see if you still have humming. If not, then you're either getting the humming from the HD500 or you have a ground loop between the two. Read this about the fan in the Velocity 300.

http://www.sevenstring.org/forum/gear-reviews/157340-rocktron-velocity-300-cooling-fan.html

 

[mcdj0nt]

I unplugged my pod from the power amp and tried a different "pre-amp" and still got the buzz