I don't think you can determine an amps RMS from it's fuses... I mean.. what do I know.. nothing.. but i really don't think an amp blows it's fuse at RMS ... just saying..
Autosound guy is a retard. an external amp for your mids and highs makes a huge difference. especially with the addition of an active high pass filter... much cleaner...
Nahh, do an ANL fuse holder, like 300A, and solder the 0 gauge terminals on the sides of Meade style, if you've seen it...plus that'll give you just a bit more protection...
25Hz? really .. damn... i still vote power noise..cheap RCAs pick up on everything...
Does it go up with you turn the HU volume up or does it go up when you turn the amp gain up?
On the bright side... If you can play that low, you can burp it at 25Hz whenever you want. lol
I don't think that's "feedback" ... It sounds like power line noise.. how deep is this "low deep noise"?
And no, there isn't really any way to test them with a DMM.
I'd say that the RCA on your deck isn't just for subwoofer output.. but I may be wrong. And if you amp doesn't have a pass thru, you can use an RCA splitter, but you need to re-set your gains when you use an RCA splitter because it will drop your input voltage.