Sub & Amp

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sunnyr83
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Tue Sep 07, 2010 1:21 pm

Im confused as to why my sub & amp is not working..I have wired it correctly the light comes on the amp but no sound from the sub or a 5'' speaker i tried. I have tried a different amp and sub and again nothing!! What is the problem? Does the (red) battery wire have to have a fuse in between it because the current one doesnt. Again the amps power light is on but nothing, Checked the settings on the headunit which say nothing about connecting an amp. Help iv got a cd full off Dub and Gregory Issacs Rumours tune i wana cruise to.
ImysE30
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Tue Sep 07, 2010 3:16 pm

I would advise on putting in a fuse between the battery and amp connection.

Has the amp got a fader switch not plugged in?

Connected the amp to the headunit correctly?
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sunnyr83
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Wed Sep 08, 2010 12:20 pm

All of the above is done except for the fuse between battery and amp. But im still getting power to the amp, had it set up in the same car and headunit when i owned the car before aswell. :mad:
ImysE30
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Wed Sep 08, 2010 1:03 pm

Try a fuse and see if that changes anything? :?

Have you tried a different amp with the same speakers?
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bmw9818
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Wed Sep 08, 2010 1:22 pm

maybe rca cables? they in properly
E30BeemerLad
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Wed Sep 08, 2010 1:29 pm

If you have no fuse in the main thick power lead then the amp can't be getting any 12v+ feed. The light coming on the amp is probably just the power switching (the feed from the head unit which tells the amp to switch on when you turn on the stereo - usually a blue lead I think)
pac1982
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Wed Sep 08, 2010 2:37 pm

Could be a bad earth
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bmw9818
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Wed Sep 08, 2010 3:24 pm

Yeah it's weird u really should have an inline fuse about 10 inches or so from the battery I've never seen a power wire without the fuse what guage is it?
mnmbm325
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Wed Sep 08, 2010 5:01 pm

the fuse is a must! but this would not do anything for sound, just stop your amp melting!! you say the red led on the amp comes on? this indicates there is power, the earth would also be proven ok if thats the case, because it would be really dull or flicker if its a bad earth. Is the blue remote cable wired in ok? this might be the problem! make sure its a good conection. the one i think is the fault would be the rca cable. most newish stereos have more than one pre out. just ensure its in the right one and not an rca connection for sound "in" to the stereo. failing all this it might be your amp! or parts in it. try adjusting gain and things. my pioneer has an option in the sound menu to put the sub "on" and adjust the high pass filters etc. only other thing i can think of mate is how you have wired your sub to the amp. is it bridged? + and - from 2 different channels? or the + and minus from the same channel (right next to each other)

hope this helps mate.
Adil786
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Wed Sep 08, 2010 7:46 pm

pac1982 wrote:Could be a bad earth
+1
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shonky
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Wed Sep 08, 2010 10:55 pm

Id say either a bad earth, The amp gain is turned down, The headunit fader is set wrong, The RCAs are not in the correct sockets or the speaker cables arent connected to the right terminals.

Or

The car doesnt have enough juice to run the amp.....Have you tried it with the engine running?
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JWaller360
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Wed Sep 08, 2010 11:39 pm

Check the settings on your headunit, my alpine has a subwoofer connection, but I could only get the sub working with the sub RCAs plugged into the rear speaker RCAs output, try that?
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grantfk10
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Wed Sep 08, 2010 11:42 pm

I'd say it's the blue remote cable not connected. :wink:
octanejunkie
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Thu Sep 09, 2010 8:20 am

grantfk10 wrote:I'd say it's the blue remote cable not connected. :wink:
+1 for the signal wire.
Either that or the RCA's are connected wrong.
sunnyr83
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Thu Sep 09, 2010 3:57 pm

Ok the blue remote wire is connected fine as is the black ground, the red battery wire is connected but does not have a fuse connected to it but the power light comes on the amp but no sound from the sub, (dont think a fuse affects weather sound comes out or not right?). On the headunit there are 2 pre-outs and a subwoofer one aswell, i have tried it in all off them i have also tried 2 different amps (power light came on both) and another sub and also a 6x9 speaker and still nothing. The only thing it could be is the jvc headunit which has no settings relating to connecting an amp. its doing my head in!!
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shonky
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Thu Sep 09, 2010 7:30 pm

Do you mean that the battery wire is missing its fuse or there it has no fuse (as in its one complete wire to the battery?)

If its the former plug a fuse into it

If its the latter, the amp should work but I would recommend adding a fuse close to the battery

You say the light on the amp glows........sometimes these will glow if theres a fault or a short (but usually a different colour to when its healthy.....i.e. Green for power on or Red for fault.

Without someone in the know looking at your wiring and set up, we could be guessing all week!
Why not nip down to your local car audio shop and ask them to take a look? If its something obvious that will only take a minute to diagnose, they may not ask for any money for doing so!
Banjo1981
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Thu Sep 09, 2010 7:51 pm

Have you checked speaker connections? and similarly have you checked for breaks in the wires?
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E30k
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Thu Sep 09, 2010 8:05 pm

this may help first was the whole setup working before if yes then it is some connections gone wrong or amp+head unit blown if not then try this i needed to switch a amp on once i had a sony head but the amp would only come on when the radio was switched on in the end i got my self a switch put it in line with the remote wire and put it to a live, switch on amp on switch off amp off but head still working good if you want to turn the amp off when going past the old bill in my case the control wire was labeled wrong it was the wire that controls the aerial
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