my amps won't power up

1) did you check your ground to the amp and make sure it is tightly secured to a clean piece of chassis with no paint under the bolt?

2)If you have a multimeter make sure your remote wire is getting twelve volts when the radio is on (you may also use a test light for this ).

3)also while you have a test light or meter handy make sure that you are getting voltage across the 12 volt side of the amp with reference to ground.

4) Since you said you tried a brand new amp one of these conections has to be bad the only way to find out would be to check with a dmm or test light if you dont have a test light buy one they are cheap you will need it agin for something in the future.

5)last thing is even though you said the fuse is good double check it . Did you check the fuse at the battery for the amp power wire?

Don't forget to check the HU for a possible remote turn on lead problem. make sure that there is 12 volts coming off the remote turn on lead.