Grounding issue between input and effects loop

[rickshapiro]

So I have a number of pedals, some that are used in the effects loop and some on the input. I have a cable that provides power to all the pedals with a single power supply. The problem is I get a bad hum when using the same power supply for the input and loop. I've tried three different power sources. I've tried process of elimination to see if I could find a pedal that was causing the problem. In the end I need to use two power supplies one on the input and a second on the loop. It cuts the hum down dramatically. I've checked my grounding at the wall, tried some line filters. There just seems to be something that is trickling down the single path. Anybody else experiencing this, any suggestions?

[sasquatch]

I experienced similar issues with my QR. I'm doing the same thing you are, except I never tried to run all devices off one supply and still had the ground loop issue. It seems like running pedals out front and other F/X in the loop tend to cause this. The first thing I did was add a VHT Valvulator to my pedal board. Among other features, it has a ground loop switch. This quieted down pedalboard noise and improved my sound, making the amp sound more like an amp w/o any pedals in front (no signal loss). However, it didn't completely eliminate the hum... I could still hear a little hum when using the gain channel. I kept the Valvulator on the board cuz it did improve my sound, but I was still looking for a way to completely eliminate the hum, and also wanted to eliminate preamp hiss and 60 cycle hum (not usually a problem but can be if power supply is questionable) so I added an ISP Decimator Pro Rack G to the rack. This unit handles noise reduction for pedals out front and anything in the loop (it's a two channel device) and also has dual ground lift switches. I wound up not using the noise suppression channel for the loop as the QR is about the quietest high gain amp I've ever played, but the dual ground lift feature is priceless. Once I pushed those two buttons in... zero ground loop hum, absolutely gone! At this time I realized the Valvulator probably did take care of the hum from out front, but didn't address any issues with the devices in the loop and how the two interact.

[hammered]

First post here ,I had the same issue with my Super Sport head that I acquired on Wednesday. I used a 1 Spot power supply to power my Maxon delay in the loop and a BB Preamp in front of the amp and the hum was there , unplugged the BB and of course the hum went away

[rickshapiro]

I purchased a Voodoo Lab Pedal Power 2 Plus the problem is no longer a problem. I still might by an
ISP Technologies Decimator Noise Reduction Pedal for whatever noise is let.

[hammered]

Oct 22, 2012 8:21:45 GMT -5 rickshapiro said:

I purchased a Voodoo Lab Pedal Power 2 Plus the problem is no longer a problem. I still might by an
ISP Technologies Decimator Noise Reduction Pedal for whatever noise is let.

Is the hum completely gone or just more tolerable?

[alerich]

Same problem with my 2006 QR (now sold) and my Splawn modified Sovtek MIG60. I use a Boss NS-2 Noise Suppressor before the amp's input. I use a second Boss NS-2 in the loop. The output of the loop NS-2 goes directly to an Ebtech Hum Eliminator and then into the effects loop return. Using only the two NS-2 pedals the hum was greatly reduced but not entirely gone. Adding the HE killed the hum entirely. My rig is dead quiet. I don't notice any appreciable loss in tone with this setup so it is minor at the most. Having a quiet rig is worth sacrifice.