Thump noise

[Screemindemon]

Ok I have pp2 and a iso5. Which is plugged in the pp2 extra outlet. Now. So I have three high current pedals hook up two on the pp2 and one on the iso 5 9v. 400ma. Now the two hooked up on pp2 is a empress Heavy and a mxr reverb. And a Echoplex is hooked up on the iso5 9v 400ma. Along with a mxr stereo chorus wich is hook in the 18v. Problem I’m having is when I turn power on board and amp then decide to tap on my Echoplex it makes ump sound like you plugged your guitar in while the amp is running. It only does it that one time until you shut down the rig. Wtf? Anybody know?

[JohnClark]

Is this the MXR EP103 Echoplex?

Does it do the same thing when it is powered from it original power supply?