No sound from premium sound sub?

[obxnascar17]

I just bought a 1991 XLT with a after market head unit. The guy I bought it from ran his own wires to the front door speakers so I took all that out and hooked up the premium amps ,I get good sound from all 4 door speakers but nothing from the sub. I cut the speaker wires going to the sub amp,buy the way the sub amp does have power, and hooked a speaker to those wires and I get no sound at all does anyone know what the problem could be !!!

 

[FHBasketball]

did you check the amp ground??? A lot of times, subs won't work, or at least sound like crap, if the amp powering the has a bad ground, or no ground at all. Also, if you have a 2 channel amp with one sub hooked up, you may have the + or - wires attached in the wrong places. If you still have the instructions, check to see how to hook up the wires. 2 channel amps have different wiring for one sub than two.