Digitech RP355, high pitch whine.

[lerceon]

Just bought the RP355.
There's a high pitch whine when I use it with headphones, with just my guitar plugged in.
(It goes 'eeeeeeeeeeeeee'....)
I noticed the power adapter is 2 pin (hence no ground right?).

The problem went away in 2 scenarios:
1) When I touch the guitar strings near the bridge.
2) I plugged in the USB cable to connect to my computer (hence creating a ground for it to go to?)

I'm not electronically trained, so I'd like to find out if this is 'normal'?
Having to plug in the USB to remove the high pitch whine doesn't sound right to me..

Can any gurus give me advice?

 

[zesn]

Yep you're right it's a grounding problem.

You can change it to a 3 pin plug.

 

[lerceon]

Yep you're right it's a grounding problem.

You can change it to a 3 pin plug.

Erm, the AC adapter is 2 pin with a block of stuff (transformer? to DC round hole for the RP355), I don't see how I can convert to 3 pin plug.

I have followed the sticky and converted my amp to 3 pin before. but this seems... different.
Any other ways to resolve?

 

[lerceon]

I got an answer from Digitech support.
They said my problem sounds like a bad chassis ground, it should not have any sound when working properly.

So I'm bringing it back to Swee Lee soon... sigh.

- - - Updated - - -

I got an answer from Digitech support.
They said my problem sounds like a bad chassis ground, it should not have any sound when working properly.

So I'm bringing it back to Swee Lee soon... sigh.