ok so a friend of mine showed up about 90 minutes ago in the rain and asked me to put his subs in for him because our other friend who was supposed to do it decided to go get a new tattoo tonight (go figure). so i let him wire up the amp while i went inside to put the speakers in the box. they seemed to be connected properly (two alpine type r 2ohm dvc wired in series to 4 ohms each). the amp was some old crossfire amp that he had wired to the same subs before but blew those in a few months. the amp is supposed to do 800 rms or something like that and is switchable between 2 and 4 channels.

heres where the problem comes in. when we hooked it up to the amp i turned all the gains down to tune it for him, but when we turned on the stereo one of the subwoofers would make a steady and very audible thump every second or so, even with the volume at 0. the second sub did not do anything. so in order to save the thumper i disconnected it. as for the other sub there was no sound, but then i noticed the amp was acting up. the power light was green, but it was quite dim. then, as if the amp was storing energy for the music, the light would go bright green and the sub would play the bass for no more than one note and then the light would begin to fade again.

now i'm no pro, but my assumption was that there was a problem with the amp. i'm not sure, it could end up being the subs, but because one sub thumped i thought it had one bad channel and because the amp itself did seem to be able to maintain proper power that something was wrong internally. can anyone help me out? this is the first time i've ever run into a problem like this and have no idea how to begin diagnosing.

 

seen this on a pioneer amp. amp is a gonner.

 

awesome, thanks danyman. i tried telling him that but he was so hell bent on telling me about how good the amp was before he lost his old subs. when he first told me about the amp he said every sub hes hooked up to it has died from him "pounding to hard". i told him him i think the amp is bad but he said the guy who rebuilt it said it worked awesome and blah blah blah...i dunno i guess some people are just thickheaded, destined for hamster subs, only keep them for a few months before they die...rip Brownie

 

lol ya might be fixable. worth it i dont know. depends on what its worth and how much it costs to fix. since by what i read its a 4ch amp and only one side works while thumping... well sounds like a power supply issue and 2 channel blown and the other 2 borderline.


i hope he gets it through his thick head that he needs to dish out some cash for a new amp lol.. either way a blown system sux. i can feel his pain :P

 

Sounds like "motorboating". Is that amplifier bolted to metal directly? If so, it may need to be de-coupled from the vehicle chassis.
Was the 4 ch. amp. bridged before being re-connected by your buddy? Have you checked his connections? Power, ground all good? Any speaker wires shorted to the vehicle chassis?

 

They are dual voice coil speakers... are the coils wired properly? If you run 2 coils on the same speaker out of phase the speaker won't move...