I think myself I have blown a noise suppresser inside the unit!!

From your description, yes, you've blown something inside the unit. There really aren't any "noise supressors inside the unit" per se, but you've certainly blown something.

Plugging the other empeg in for diagnosis really helped to be sure.

And yes, it's important to know the difference between a simple extension cable and a wiring adapter. It might be helpful to know exactly what wires got connected to what other wires. For example, if you applied 12 volts to the headlight sense, or connected one of the audio connectors to ground, or what? But from your own admission, you don't know what all of the wires do and didn't know what the adapter did, so you probably can't tell us that.

Your only option may be to send it in for repair. It doesn't sound simple.