Whistling/Humming with 4x4 using a Digitech Whammy DT

General discussion and tech talk about the industry standard Pedal Power line of power supplies.
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guitarsy
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Whistling/Humming with 4x4 using a Digitech Whammy DT

Post by guitarsy » Mon Sep 24, 2018 6:23 am

Hi,

Has anyone else had this issue? I have tried different cables and nothing changes. The other large pedals that are being powered by the 4x4 is the Boss DD-500, MD-500 and RV-500. I have a EH Worm using 2 12v slots and a VL labs splitter to provide the right power to the pedal. I can't see anything that should be causing this hum? Whammy works fine when powered by itself.

Any help/suggestions would be greatly appreciated!

Rez
Posts: 227
Joined: Thu Sep 01, 2011 10:31 am

Re: Whistling/Humming with 4x4 using a Digitech Whammy DT

Post by Rez » Tue Sep 25, 2018 5:18 pm

Are you using both the 9V and 12V outputs of either 9/12V output pair?

If yes, that may be the root cause... as the 9V and 12V outputs of a 9/12V pair are not isolated from each other, to avoid possible ground loop hum/buzz, the general recommendation is to use only one or the other of the pair.

Any better?
Cheers,
Ben Resnick
Voodoo Lab - Tech Support

guitarsy
Posts: 4
Joined: Wed May 08, 2013 6:19 pm
Location: UK
Contact:

Re: Whistling/Humming with 4x4 using a Digitech Whammy DT

Post by guitarsy » Wed Sep 26, 2018 1:34 am

Hi,

I am using all of the inputs for pedals, should I use only one of that pair? If so that would drastically cut down how many pedals I can power.

Thanks again

Rez
Posts: 227
Joined: Thu Sep 01, 2011 10:31 am

Re: Whistling/Humming with 4x4 using a Digitech Whammy DT

Post by Rez » Wed Sep 26, 2018 1:03 pm

What are the specific pedals you are powering (and which one is using the 18V output)?
Cheers,
Ben Resnick
Voodoo Lab - Tech Support

guitarsy
Posts: 4
Joined: Wed May 08, 2013 6:19 pm
Location: UK
Contact:

Re: Whistling/Humming with 4x4 using a Digitech Whammy DT

Post by guitarsy » Thu Sep 27, 2018 5:16 am

Hi,

The pedal using the 18v using a splitter to 2x9v is the EHX Worm pedal. The hum seems to happen when I have the Digitech Dirty Robot plugged in and the Digitech Whammy DT?

The board consists of -

*Boss RV-500
*Boss MD -500
*Boss DD - 500
* EHX Blurst
* EHX The Worm
* Digitech Dirty Robot
* Boss Expression Pedal (passive)
* Pro Co Rat
* Boss GE-7
* TC Electronics MojoMojo
* Jim Dunlop Cry Baby
* TC Electronics Hyper Gravity
* TC Electronics Spark
* Boss NS-2
* TC Electronics Polytune 3
* Digitech Whammy DT
* Ernie Ball VP (passive)
* Custom Patch bay for fx loop signals to amp (passive)

Thanks again

Rez
Posts: 227
Joined: Thu Sep 01, 2011 10:31 am

Re: Whistling/Humming with 4x4 using a Digitech Whammy DT

Post by Rez » Fri Sep 28, 2018 12:36 pm

Thanks for the details.

Pedal Power 4 x 4 has eight isolated outputs. As ideally each pedal should be powered from an isolated output and you've listed 18 pedals... I would not expect 4 x 4 to power them all sufficiently.

Also, as the 9V and 12V outputs of a 9/12V pair are not isolated from each other, to avoid possible ground loop hum/buzz, the general recommendation is to use only one or the other of the pair.

That said... as long as it is to power a 9V pedal and a 12V pedal and their combined current requirement is less than 400mA, then yes, both the 9V and 12V (of a 9/12V pair) can be used simultaneously.
Cheers,
Ben Resnick
Voodoo Lab - Tech Support

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