fx chain problem?

Hi
>
>I have a problem with my fx chain. I own a vox wah, a small stone, a boss overdrive and a boss delay.
>I have the delay as a sent, The problem is that I am loosing power its time I turn on the small stone..
>do you know what might be the problem? Has to do with the order? all the pedals except from the wah are powered by ac adapters.
>
>thanks