i've been on about this before basically i have an amp fitted in the boot i had a problem with wiring which i sorted but now whenever i hit a phat bassline the sub cuts out slightly not all the time just every now and then such as on gorrilaz track

dare which has a massive bassline.

most of the time it can handle the bass what i was wondering is could this be a ground problem as most of the time its fine the gain is down quite low as i have 5v pre outs

i am using the cd changer mounting plate as a ground which i have cleaned around with sand paper i have 4 gauge for the 12v and ground

does anyone have experience with this problem or can anyone reccomend a better ground ideally without having to drill anywhere or if drilling is best suggest a point that is safe (pics would be good)

It could possibly be an earth, however it could also be that your amp is just plain running out of current from the car to hit that base note.

Do you have a large capacitor in the supply line to your amp? You can buy 1Farad capacitors on 12v specifically for ths purpose and it sounds like this may be the problem you are having. They are not too expensive:

http://www.maplin.co.uk/Module.aspx?ModuleNo=25446&&source=14&doy=30m6

If you do go down this route, please please please be very careful when fitting it and make sure you don't just disconnect it without reading the instructions and make sure that all connectors are always covered up.

This sort of thing has the potential to seriously injure or even kill you with the sorts of currents you can use, and if you manage to do it wrong a cap can catch fire/explode.

IF YOU ARE NOT 100% SURE YOU KNOW WHAT YOU ARE DOING THEN GET A PROFEESSIONAL FITTER TO FIT SUCH AN ITEM.

Also you might want to get a ground loop isolator in so that your amp doesn't pick up on things such as ignition noise etc.

Right sorry about caps, but I don't want anyone hurting themselves on my info, and as always everything is done entirely at your own risk.

been down the power cap road years ago had one fitted way back in the day

in fact my fitter at the time told me i was the first person in cardiff to have one

it cost about 300 notes at the time thats how long ago it was

i don't really want to go that far with power caps the install as this is only a sub amp setup

like i say i did the massive b00b tube in the boot years ago and SWMBO moans about fitting shopping in there already

the other thing that puzzles me is the fact that it will play for ages fine on heavy bass tracks but then sometimes it gives up

thanks for your input mate

also it aint that big an amp either its 220rms in the past i had nearly 1000 rms worth of amps running and didnt need a cap for any cutting out reason just the fact that my lights were dimming and cos in those days i would buy anything my fitter recommended

It might be worth putting a mulimeter out and if you can reproduce it regularly then watching the current across the poer wire and the quality of the ground between the wire and the chassis.

I have to say that 220w could be enough to cause a car battery problems as a cap releases that power v quick where as a battry is pretty slow to react to large drains.

Anyway good luck finding it as these faults are a pain in the **** to fix when they are intermittant.

sorry i aint been on for a few days can you run that one past me again i have to check the ground with a multimeter

how excatly do i do this never had to do this in the past

please advise

Could it be the amp is simply overheating and cutting out?

i dont think so cos it will play some tracks cranked up just fine

Just connect the multimeter to the ground point you are using and the amp end of the ground connection (making sure the multimeter is insulated probes and can take the power you are possibly pussing through it).

The amp could be faulty and cutting out or thermally cutting out. I'd go with that more or a lack of power as I was suggesting rather than an intermittant ground if the thing work sok most of the time, except on certain bass notes.

Just connect the multimeter to the ground point you are using and the amp end of the ground connection (making sure the multimeter is insulated probes and can take the power you are possibly pussing through it).

what kind of reading am i looking for around 12volts i suppose

am i right or am i just thick

How much is the cone moving? If its over-extending then you could possibley be shorting out the voice coil. Might be worth taking the sub out of the box and just checking the wire that goes from the speaker cable terminals into the cone itself and make sure they're not touching. Also have a sniff around the voice coil area. If it smells funny (can't remember what it smells like... I want to say biscuits but don't quote me) you're burning the voice coil out. Also check that the speaker cable + and - isn't touching anywhere, a stray strand bridging or something like that. Check the amp end and sub end, and any connections inbetween. I would say it sounds like a short somewhere.

If its to do with it not getting enough juice, which seems unlikely then the power light (if it has one) would go out or dim when it cuts. If the amp has a thermal protection circuit built in, it should do something to let you know its tripping. Check through the manual and see if it mentions it. Again, to test the power side of things, try it with the engine off and then with it on. If it still cuts out at the same point its not the power as car running should give the amp around 14.4v, off it will only get 12v.

Finally, caps aren't really worth getting for the majority of applications. Check out Talkaudio (part of caraudiodirect.com) and do a search for capacitors. They will explain it better than I can.

i can promise that just one little'ish sub isn't enough to cut your voltage low enough to make an amp cut out.

mine only cuts out when i have it quite loud on a very bassy track and i have 4x300W dual voice coil subs.

for a decent earth use the seatbelt mounting bolt like i said before. works fine for my setup that is wired in zero gauge.

right i finally got round to getting a multimeter

i got 12v when switched off and 14.3-4 when running

when i checked the ground it showed 0

surely that aint right amp was still running

help i'm a little confused by all this