Grounding issue DC powerbrick effects loop/front of amp

[plapnab]

Hi all. Was wondering if anyone else had this issue. I have tried two multiple pedal power sources (DC power brick/multi prong adapter) to run my pedal board and have run into the same problem each time. Whenever I hook both my front of amp effects (tuner, wah, tube screamer, phase, isp decimator) on the same circuit as my effects loop pedals (10 band eq, delay, reverb) I get a grounding hum in my gain channels. When I run two separate power sources for loop and front the noise goes away...quiet as a mouse fart. Checked all the pedals and cables...everything works fine. I'm kind of disappointed because I recently bought a DC powerbrick which I though would get rid of this issue. However, like the multi prong adaptor...works great on one chain, hums when powering both. Is this normal? :?:

 

[ibanez4life SZ!]

Which DC power brick?

I've heard such problems with the Dunlop model.

I haven't had the slightest problem with the Voodoo Labs Pedal Power.

 

[fluff191]

The Dunlop brick doesn't use isolated grounds like the Voodoo from my understanding.

I own and love the Voodoo Lab PP2 as well.

 

[screamingdaisy]

It's normal.

If you want to use a single power supply you need something with individually isolated taps. The Pedal Power 2 works perfect for this.

 

[94Tremoverb]

Yes, it's normal. If your power supply doesn't have isolated outputs, you can sometimes cure the problem by removing the ground connection on one of the sockets (leaving the circuit to be completed by the signal cabling) or adding a resistor in the ground path to partially lift it. I fixed mine by adding a 100-ohm resistor to the socket that supplies the power to the loop pedals. (This probably means that a fair amount of the current is going via the signal cables too, but it acts as a backup if there's a bad connection anywhere.)

 

[plapnab]

Which DC power brick?

I've heard such problems with the Dunlop model.

I haven't had the slightest problem with the Voodoo Labs Pedal Power.

It's a Dunlop. Apparently, it's normal. But, kind of a bummer...really cleaned up my pedal board the first time I had it wired.