Speakers Have Pulse.

Well things never cease to amaze me. Month or so ago my cheese Lighting Audio amp blew up. I said fine I am going for Alpine. So I bought a Mono 350 RMS amp. I installed it and it was all good until it started clipping out and comming back on. Then off, then on, and stay off for a little bit. I can get the sub to beat if I keep the volume down real low and it will come on. Then if I turn it up the amp quits. :mad: I turned down the gains and stuff and no effect. Grounds are very good. I get 12 volts (14.4 at the battery) at idle and 12 volts with engine off. I have altenator whine and thats pissing me off. I do have crappy RCA cables. :tsk: If I unplug the RCAs at the amp the front speakers stop pulsing. I am running out of ideas. I have already taken the amp back and got a new one and it still does it. I am leaning towards the head unit itself. After all it is a JVC. Thanks

Also will altenator whine damage anything? :shrug:

:bump:

No alt. whine can’t hurt anything. I would try a new set of RCAs, [just run them right from the HU to the amp over everything] and if the HU has more then one set of preamp outputs, try the other ones, also I would check the subs, check the impedance, [can’t be less then 2ohms] also need to check for a short, [burnt VC] a “cheese” amp, or any amp for that matter, can damage the sub/subs when it “blows up”. Easy test is plug in another sub to the amp. :hmm:94

Tried a new set of RCAs. The deck has to pre outs and it does the same on each. I have a 350 Mono Alpine V Power amp pushing a single type r sub. Its a single voice coil. If I turn up the volume past 12 it shuts off. If I turn the deck off then back on the sub will hit. I dont remember how to check the impedance. I dont have another known good sub currently. I will check with one of my friends. Also how would I check for a burnt voice coil?

multi-meter on the subs (well, decent multi-meter… the cheese ones are WAY off) - should read around 8, 4, or 2 if it’s ok (depends on how the subs are wired)… anything else and the sub’s pooped!
also check your trigger wire (amp remote wire) if it’s grounding out somewhere (common issue). as for alt. whine, check your head’s ground or run a new one back to the amp so the amp and head have the same ground point.
make sure your amp ground is a SOLID connection - right to metal, not through a seat bolt, and SAND IT DOWN TO BARE METAL. after you screw it down, hit the whole thing with some di-eletric grease to prefent rust.
also, to elminate rca noise, run them outside the vehicle to the amp, as far fom anything as possible.
HTH.