Guest noggy Posted April 11, 2009 Share Posted April 11, 2009 ok, so im 18 and perhaps a little bit mad, but i have installed four 6x9's and im trying to install a subwoofer with its own amp. now, i did study electronics when i was younger, but im baffled... the Amp for the sub, is wired straight to the battery terminals to give it the best 12v and ground possible. it was working fine for 20 mins, now everytime i switch the system on it blows the 25amp fuse on the Amp. whats the problem? the Amp says that it should have a 25amp fuse and im not even playing music through it and it blows. whats the deal? Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted April 11, 2009 Share Posted April 11, 2009 Probably a dead short somewhere. Put the electronics books away, break out the multimeter and look for the low resistance. I've got a pair of 6x9s in my Ninety - I had a 12" sub but realistically I couldn't hear it at any speed. Quote Link to comment Share on other sites More sharing options...
Guest noggy Posted April 11, 2009 Share Posted April 11, 2009 hmm... terribly annoying! gotta find a new battery for the multimeter... someone left it turned on..... Quote Link to comment Share on other sites More sharing options...
Night Train Posted April 11, 2009 Share Posted April 11, 2009 Check the sort of fuses you are using. I think they need to be slow blow fuses to cope with the start up current. Alternatively, I assume that the amp is wired directly to the battery via the 25 amp fuse and controlled on and off by the head unit? If the fuse only blows when the head unit is turned on then the fault lies in the amp. Any chance of damage or something dropping into the amp or its connections? If the head unit controls a relay in the amp supply cable then the fault could be in the cables if you have snagged one and damaged the insulation some where. I last installed an in car entertainment system when auto reverse cassette players were the latest thing so I could be wrong about how it all works nowadays. Quote Link to comment Share on other sites More sharing options...
Guest noggy Posted April 11, 2009 Share Posted April 11, 2009 hmm... actually night train.... i think you might be on to something.... The fuse, is actually on the side of the amp, not in the wiring, and it only blows when my headunit is turned on, which triggers a relay in the amp to turn it on. the fuse i blew first was a different kind to the ones ive been putting in, it was still 25amp but looked slightly different... i'll look into slow blow fuses and have a poke about in the daylight Thanks Quote Link to comment Share on other sites More sharing options...
task Posted April 11, 2009 Share Posted April 11, 2009 Also worth noting but probably not relatd to this current fault, you want a short as possible earth rather than going back to the battery. Quote Link to comment Share on other sites More sharing options...
Guest noggy Posted April 12, 2009 Share Posted April 12, 2009 Also worth noting but probably not relatd to this current fault, you want a short as possible earth rather than going back to the battery. how come? surely the battery is better? Quote Link to comment Share on other sites More sharing options...
GKP Posted April 12, 2009 Share Posted April 12, 2009 There's potential for noise to enter the system with long earth leads. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted April 12, 2009 Share Posted April 12, 2009 My take is, wire it up so it works. There's plenty of scope for noise to enter the system between the speaker and your ear, you won't be able to hear a buzz or whine over your engine/gearbox/tyres/missus. If you build a system to compete with all of the above you'll just damage your hearing. My amp says 1000W on it but there's no way I can hear it above 70mph - I've lost a radio station in the past and my brain keeps singing the song for me because it was only picking up every other note above the background noise Quote Link to comment Share on other sites More sharing options...
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