Steady tone from sub?

Question

We were running my stereo in my truck at a party so it was on at a high level for an extended period.(4-6 hours maybe) The sub started to put out a continuous low tone even when the cd was stopped. Music would still play as well but you could hear the steady tone along with it. After shutting it off for a while it seems to work fine again. Was this a temporary problem? Overheated maybe? Could this be a sign of something on the verge of failure? I'm running a panasonic head unit (CQ-C8803U), Pheonix Gold 1200.1 amp with a PG 1 farad cap powering a single JL 12-W7-3. I know it is not electrical interference because I have been running this amp/sub combo for years with no problems and was profesionally installed with a Rockford Fosgate #2/o wiring kit. Cab is insulated with Dynamat and replaced oem speakers with 4 5 1/4 MB Quart speakers just running off the deck.(70Wx4)

Answer 1

"I know it is not electrical interference because I have been running this amp/sub combo for years " - don't be so sure buddy ,things go wrong where its least expected.

things you should check

- try changing RCA cable

-try running with another head unit - or connect it with you ipod or any other portable music player ( take a connector of 3.5 mm jack which spits in to rca - comes for 1$  ) - this will tell you if the head unit is damaged or not.

if still problem persists amplifier may be damaged-

hook the sub to friends amp..if still problem comes - sub damaged