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post #1 of 16 (permalink) Old 29-10-2010, 10:33 Thread Starter
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Best Earth Point?

I have just got a new amp for my sound system, Its going behind the passenger seat. Were would you say the best earth point would be?
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post #2 of 16 (permalink) Old 29-10-2010, 10:42
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Originally Posted by coleman758 View Post
I have just got a new amp for my sound system, Its going behind the passenger seat. Were would you say the best earth point would be?
Passenger seat railing screws. No need to drill any new holes and it's just there.
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post #3 of 16 (permalink) Old 29-10-2010, 14:04
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I think Liverpool is one of the best Earth points...
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post #4 of 16 (permalink) Old 29-10-2010, 15:12
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I would very seriously consider upgrading the front battery earth to body cable, it is very small as it is. It is a big bottleneck in the current return path and will strangle the output from the amp.
Anything other than a small RMS amp will need this doing, plus the positive feed from the battery to alternator and the engine to body earth cable will need upgrading. An alternator from the 25 derv and a bigger battery would be a good thing too as all the standard wiring and charging circuit components are not enough for keeping a decent output amp fed with all it needs.
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post #5 of 16 (permalink) Old 29-10-2010, 15:17
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I would very seriously consider upgrading the front battery earth to body cable, it is very small as it is. It is a big bottleneck in the current return path and will strangle the output from the amp.
Anything other than a small RMS amp will need this doing, plus the positive feed from the battery to alternator and the engine to body earth cable will need upgrading. An alternator from the 25 derv and a bigger battery would be a good thing too as all the standard wiring and charging circuit components are not enough for keeping a decent output amp fed with all it needs.

Depending on how big the amp is then yes a definite +1 on the above. You might also consider a few big 1 farad caps - they give you a sporting chance of the instantaneous current delivery you need for nice punchy bass.
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post #6 of 16 (permalink) Old 29-10-2010, 15:20 Thread Starter
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its 1200watt four channel
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post #7 of 16 (permalink) Old 29-10-2010, 15:26
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PMP or RMS?

Either way I would go with bigger battery. (Most of the Serious ICE boys go for a dedicated battery and a split charge system).

Best tip is try it and see - if your headlights dim in time to the beat you need a bigger battery and probably a few chunky capacitors to help you through the lumps! (and matching alternator if you put a bigger battery on of course)
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post #8 of 16 (permalink) Old 29-10-2010, 16:14
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Its going to be peak. Upgrade your wiring first, then alternator maybe.
A power cap s the worst thing you can put into your power supply, it actually puts more strain on the charging system with the extra drain needed to recharge the cap whilst doing nothing for the amp supply. A bigger battery could be needed, but definatly upgrade your wiring.
The easiest test is count the amps the fuses on the amp add up to, then consider your altenator is probably around a 45amp output in total, take away what your lights use, what your wipers use, and what your engine electronics use... There's very little spare. When your lights dim it's the alternator and battery failing to keep up with demand, this leads to voltage drop which send the amp into clipping whic can blow amps and speakers.
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post #9 of 16 (permalink) Old 29-10-2010, 16:27
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Hmm, all interesting to read. Never had any battery or alternator problems on my F with the amp, sub and nitrous bottle heater running all the time...
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post #10 of 16 (permalink) Old 29-10-2010, 16:29
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This may seem an odd Q, but how do you upgrade an alternator? Never seen an uprated version of the standard OEM spec, even on aftermarket....
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post #11 of 16 (permalink) Old 29-10-2010, 16:38
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The "BEST" earthing point will be the negative terminal of the battery, otherwise any good fixing screw that's not rusted on the chassis
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post #12 of 16 (permalink) Old 29-10-2010, 16:41
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Originally Posted by andycolm View Post
A power cap s the worst thing you can put into your power supply, it actually puts more strain on the charging system with the extra drain needed to recharge the cap whilst doing nothing for the amp supply.
Andy - No disrespect but I disagree. Yes the cap bank takes extra energy during its non-peak charging cycle, but allows delivery of high current without voltage dips on peak demand - far more so than a battery which is 8 foot away via sub-optimal wiring.

Depending on what type of music is being played the demand ratio usually favors the slow charge, occasional peak discharge scenario that a suitable capacitor bank provides.

If anything adding a cap bank provides protection from damage likely to be encountered from "clipping unders"

I could trot out the maths - but there is a frequently quoted article that saves me the time : http://www.caraudiohelp.com/newslett...citor_myth.htm
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post #13 of 16 (permalink) Old 29-10-2010, 16:44
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I still don't understand why people want mega watts of music, There's enough power in the standard radio isn't there. If you spend money on amps, speakers, capacitors, head units................. you could make the car go faster or handle better

Just me ranting as I am getting old and starting to listen to Radio 2 hahahahaha
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post #14 of 16 (permalink) Old 29-10-2010, 16:48 Thread Starter
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Originally Posted by Cossy Abuser View Post
I still don't understand why people want mega watts of music, There's enough power in the standard radio isn't there. If you spend money on amps, speakers, capacitors, head units................. you could make the car go faster or handle better

Just me ranting as I am getting old and starting to listen to Radio 2 hahahahaha
I'm the opposite, because of cost on insurance I can't go stupid but I enjoy music! It's not for the loudness more so for the quality
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post #15 of 16 (permalink) Old 29-10-2010, 16:57
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Originally Posted by Cossy Abuser View Post
I still don't understand why people want mega watts of music, There's enough power in the standard radio isn't there. If you spend money on amps, speakers, capacitors, head units................. you could make the car go faster or handle better

Just me ranting as I am getting old and starting to listen to Radio 2 hahahahaha
I like to be able to still listen to mine when i'm driving down the motorway with the roof down. Then again I've spent a lot more on engine, suspension and brakes than I have on audio anyway
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post #16 of 16 (permalink) Old 29-10-2010, 17:12
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Originally Posted by g7nbp View Post
Andy - No disrespect but I disagree. Yes the cap bank takes extra energy during its non-peak charging cycle, but allows delivery of high current without voltage dips on peak demand - far more so than a battery which is 8 foot away via sub-optimal wiring.

Depending on what type of music is being played the demand ratio usually favors the slow charge, occasional peak discharge scenario that a suitable capacitor bank provides.

If anything adding a cap bank provides protection from damage likely to be encountered from "clipping unders"

I could trot out the maths - but there is a frequently quoted article that saves me the time : http://www.caraudiohelp.com/newslett...citor_myth.htm
Just when you thought tyre threads on here were controvertial
I sit on the side that says you would be far better off with a second battery for the money as they are far more effective than caps.
FAQ for car audio power supply questions http://www.talkaudio.co.uk/ipb/index...-power-supply/
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