Getting a tone off my EP Boost

[JParry335]

Anybody else get this? When I turn it on, doesn't matter how high I have it turned up or down, I get a constant tone that just happens to be what a b string is.
Soon as I turn it off it's gone.
It's at the end of my chain and I'm powering it with 18V from a DC Brick if that means anything at all. It hasn't always done this but is very consistent at it now.
Quite annoying.
Suggestions?
Aside from leaving it turned off

 

[Crimson Queen]

How are powering it? 60 cycle hum is between a b and b flat.

 

[JParry335]

It's at the end of my chain and I'm powering it with 18V from a DC Brick if that means anything at all.

^^^

 

[Crimson Queen]

Is the powering cable inverting the polarity? Does it have a different coloured end?

 

[Reckedtrek]

Power it with a battery (yes- it'll be 9v for the test) and see if it still has the issue. I'm guessing it's the power source, and this will prove (or disprove) it. Batteries don't add noise.

 

[JParry335]

Is the powering cable inverting the polarity? Does it have a different coloured end?

No, it's the same as all the other cables.

 

[JParry335]

Power it with a battery (yes- it'll be 9v for the test) and see if it still has the issue. I'm guessing it's the power source, and this will prove (or disprove) it. Batteries don't add noise.

I didn't try a battery but I did change it back to 9V and the noise is gone!
Thanks all!

 

[Reckedtrek]

Power supply issue most likely.

Enjoy your EP Boost!

 

[crambone]

I run my EP at 18v with a DC Power Brick and do not have this issue but glad to see that you isolated your problem!