Don't feel bad I bought a Kicker SX900.4 from a member here not to long ago was supposed to be a good amp. Well I waited 8mos before testing it, and at the moment I really needed it, it let out the magic smoke of death. I went through the amp as I repair my own, and noticed it had two blown power supply fets, replaced the whole bank on that side to keep it all even. I tested, sounded great, reassempled and installed. Well went to start it up today and POP there goes another. I was in a hurry when I did it but I went further through the amp and looked inside of the keepers to notice it was blown before and that was probably why it came in a brown refurb box. The set of fets that were replaced by Kicker had broken solder joints from using a cold iron and it was a down right sh!tty job by them. I went through and replaced all 12 supply fets and this thing sounds great. Moral to this story is you never know what you are getting when you buy second hand and without a warantee, so beware. I would have paid $150 for that blown amp lOl. Polo..
BTW- I have a IA40.1 and it has been the best amp I have ever owned, has outlasted my DD Z1a....