harry007

i just bought a jbl sub and amp off a mate. I know its all in good knick, because i'm always with him. So i've installed it in my wagon, powers up fine etc etc. But as you turn the volume up higher it cuts out randomly all over the place?? I tried to lower some of the settings but no joy? and i know for a fact this sub has been played louder in my mates standard focus hu, im running one of the new jvc dvd players things. so what is causing it to cut out so randomly, its so annoying because it really does sound good to

have checked the grounding wire, its fine, power is fine. I did have a fli active sub, that did it too when i first had it, but did suming to cure it, cant remember...? (protection light keeps coming on)

gotmashed

remote wire ok ?
has it got air round it (over heat)

redlightening

r u using the correct size fuses it seems silly but something to be checked (the one in the amp)

harry007

the remote wire is fine, fuse should be fine as it was supplied as a package from halfords. just turned down the input signal, did help, but now not loud enough?? so seen the specs of my head unit it should give out 5v, but the amp accepts 6v? wtf?

RobP

Is it running just the one sub? Or a pair ?

With some amps if they are running two subs or more they need to be wired in series rather than parallel. Otherwise the amp sees too low a load in ohms and overheat and cut out and back in again.

Other than the other suggestions this is all I can think of.

Rob

P.S. Check there isn't a strand of speaker wire shorting across + and - teminals at both amp and speaker end.

BigRed

Is the amp bridged?? If so then you MUST check the loading that the amp is seeing EG 4ohms,and check with the amp spec that the load you are showing it is acceptable, this sounds like the most likely cause in your case. Is the amp getting very hot??

The other problem could be that the amp is clipping, and causing the shutdown to protect the subs from being damaged, this is down to correct level matching.

I had this problem with a Viper amp running an RE SX12(1 ohm) turn up the volume and it would quit, I checked EVERYTHING in the setup, levels, speaker connections, power cables. I DID find the problem,after a long time searching, and it was down to the earth connection, I replaced the cable(4 awg) with 0WAG cable and fitted a huge bolt down connector to it, made sure the body work the the connection was fitting to was VERY clean and no paint left, bolted it down and everything worked fine, re-painted the area where the connection was made. I also fitted a new battery to my car, one of the new calcium types, I do run a split charge systen anyway but my OEM battery was getting very tired.

It can be very annoying , but double checking ALL work is worth while to find problems, you say you had this problem with another sub, have you used the same cabe??? if so the problem lies in them particular cables.

Another one could be under voltage protection, check you voltage output whilst running your amp, does it drop below 11 volts?? if so you have an alternator or battery problem.

chiark

What power cable are you using? How have you earthed the setup?

Also, bear in mind that the earth cable needs to carry the same current as the supply, and needs to be connected to a good ground.

Don't worry about headunit/amp input voltages: that's what the gain is for on the amp.

Buster-WRX

Thought I would offer my ten pence worth.

I have recently re-installed 2 JBL Legend amps in my MY03 these were bought by myself 6 years ago then sold to a mate.

Got them back and have had them fitted by a specialist.
Problem is the 4 way cuts out at random times especially when going round a right hand bend!!!

Anyway after the fitter checking all the wiring (earth,power remote and everything else) he has advised there could be a dry joint somwere in the amp.
Apperently if they have been sat for a while and not being used this problem can develop.
He has advised £35 to re-work and find the fault.

Might not be the same thing but just a suggestion......

kendz

Sounds very much like it could be the way the sub is wired as mentioned above. What sub (ohm rating) and amp is it? and how many channels.

Also if your lights are on and you crank it up do they dip when it cuts out, maybe your battery not providing enuff juice, more likely to be above though.

Matt