stereo killed alternator

Kowalski · Post by **Kowalski** » 18 May 2005, 14:58

N90333C ALTERNATOR XANTIA HDI 150AMP + aircon
GSF do an alternator that will do 150 amps, I thought the 120 amp one on my Xantia was excessive. At 14.4v 150amps is 2160 watts, what does the Xantia have in it that needs 2kw to run it? Water preheater, glow plugs, heated rear screeen, 4 headlights plus fogs and sidelights, what else? It must be for Mosser's stereo.

jeremy · Post by **jeremy** » 18 May 2005, 15:06

There are a couple of points here relating to power of amplifiers. the generally accepted accurate output is the RMS output which is generally half or less of the publicists figures, called music power or whatever. An amplifier will only produce this power for heavy bass notes and its quite interesting to connect an analogue meter in the circuit and see what happens.
Generally the output is limited by the power supply and unless you use something like a welding transformer its difficult to get enough power for mains units and keep them small and running cool. there have been many advances in transformer/rectifier design in the recent past and modern power supplies are much better.
So having established that conventional mains power supplies are a problem - whats nearly ideal - the lead acid battery - smooth with the potential to provide enormous current instantly - hence the enormous power available in car amplifiers.
I seem to remember a formula from years back (Maximum power theorem?) which simply said that max power is produced when output resistance equals devise resistance. - So if you have an amplifier producing its maximum output into a 1 ohm speaker it has an internal resistance of 1 ohm - and if you connect it to an 8 ohm its output is less. Great - but you can't find 1 ohm speakers - and 8 seems to be a standard!
One day I'll see if the tape player in my BX works - only had the car 5 1/2 years!
jeremy

Kowalski · Post by **Kowalski** » 18 May 2005, 15:27

A good way to work out the actual power of a device is to have a look at what its input power rating is like. With cheap computer speakers you get a power brick, have a look at its output voltage/ampage and you've got the maximum RMS wattage that the speakers can handle. The same goes for car stereos although there you might have to look at fuse ratings...
Mains power supplies have improved a lot over the years, switching mode power supplies have come along. Switching mode power supplies tend to be noisy (even with BIG capacitors), cheap ones are very noisy so top end hi fi gear use toroidal transformer which are quieter. I would agree that lead acid is a smooth power source, but you've got to charge them somehow....

jeremy · Post by **jeremy** » 18 May 2005, 15:33

The other problem is that the internals of most amplifiers don't run at 12 volts - so you need something like a 9 volt battery and it all gets a bit complicated. I suppose if you wanted to use a lead acid you would break the amplifier at the power supply stage and connect in your battery here, then simply arrange a battery cahrging circuit - ie something with a smoothish transformer to charge. You could even arrange for it to turn off while you were using the hi fi if you wanted the ultimate smooth supply.
jeremy

Mosser · Post by **Mosser** » 18 May 2005, 16:10

Robin, i wasnt looking for any sympathy, my system is working perfectly and i'm vey happy with it, i never play it loud through towns and villages and turn it down at traffic lights or slow traffic as i dont like to advertise whats in my car,
The figures are genuine, i am using rockford forgate amps that quote genuine rms outputs at 0.1%THD, not like the newer noname amps that quote their figures at 10%, and i dont use the head unit amp as they are useless in a decent system, my system will blow an 80 amp fuse and i have had to put a 120 amp fuse in for the wiring protection, 1.3KW is about right for the amps i am using too, i am running 2 12" rockford subs in a sealed enclosure firing forward in the boot, Focal components in the front doors and rockford in the rear doors, with crossovers under the passenger seat footwell
If you want a good ICE forum, visit www.icecavern.co.uk

ActivaV6uk · Post by **ActivaV6uk** » 18 May 2005, 16:34

Looks like a good forum thanks.
Andy

uhn113x · Post by **uhn113x** » 18 May 2005, 17:03

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Sl4yer

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Robin

Mosser, if we SHOUT really loud can you hear us? What on earth do you want 110 amps of amplified power for in a car?
If this is the kind of volume that disturbs the peace and general quiet in our village every night from cars driving through with bass and volume up high then I personally think it should be illegal.<hr height="1" noshade id="quote"></blockquote id="quote">
Actually, it is illegal Robin. But as usual the police can't be bothered, unless they happen to pull alongside one at lights.
I'd have them all pulled, then prosecuted if they don't have correct insurance on their (usually heavily modified) cars.
As for an ICE forum, there is probably one on the Max Power website.
<hr height="1" noshade id="quote"></blockquote id="quote">
D'you think that they can spell 'forum'
Aw, c'mon, it's nothing that both barrels on a 12-bore into the speakers won't fix [}:)][;)]

MW · Post by MW » 18 May 2005, 19:14

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Mosser
my system will blow an 80 amp fuse and i have had to put a 120 amp fuse in for the wiring protection, 1.3KW is about right for the amps i am using too<hr height="1" noshade id="quote"></blockquote id="quote">
I find that a four inch nail makes a useful substitute for a fuse on the annoying occasions when this happens. I mean, there I'll be, minding my own business and quietly cooking my breakfast on the amplifier casing, when suddenly phut, out go all the lights.
I've tried transferring the fuse from my uprated air conditioning unit, which I got from an old bus in Barcelona, and which now sits where the front passenger seat used to be. But it's no good, with the aircon switched off the smoke from the sausages just fills up the whole car, and it spoils the leopard-skin headlining something rotten. Yes, there are times when a motorist's best friend is his bag of nails. I expect your neighbours would agree.[:D]

Mosser · Post by **Mosser** » 18 May 2005, 19:46

MY neghbours have never heard my car hifi and dont even know i have such a powerful system, just because a system can go loud doesnt mean it is run at 140 Db all the time, it was built for sound quality first, but also happens to be able to go very loud, that is the nature of a decent quality hifi, show me a system that sounds as good as mine that isnt able to produce similar volumes,
Its quite a home playing classical pieces and piano solo's, but it also had the ability to reproduce drum and bass the way it was meant to be played (loud), I can pick out every instument and the slightest imperfection or sound in a symphony orchestra thanks to the liquid cooled titanium domed tweeters, and on the other hand with a bit of drum and bass, i can make my skin move like it is about to separate from my bones, the shock waves are surreal and the whole system really has to be heard to be believed,
Some of you seem to think that just because i have a very good (and loud) hifi in my car, that everyone around it is going to hear me from a mile away, this isnt the case and you are misjudging me, you dont know me and yet you are lumping me in with the nova and saxo chav's that drive with their cheap and nasty system running near full volume just to annoy everyone, that isnt me, my system is totally hidden and my car looks completely standard if you look in the windows of my car, there is no way of telling that there is 2 grands worth of hifi equipment in there without actually sitting in it and listening to it
You would be pretty stupid to put a nail in place of a fuse that is there to stop you car catching fire, its to protect the wiring and guard against short circuits

bxbodger · Post by **bxbodger** » 18 May 2005, 20:08

Well said!!! You need the power to get the clarity.
Small overdriven amp-lots of distortion.
Big barely running amp-clarity!!!
Drifting off topic a bit, Denny Stratton, the ex Iron Maiden guitarist, owned a pub in Stratford ( E15, not on Avon....) for a while and used to play there himself regularly, with a tiny 15 watt Marshall Amp- people who hadn't heard him used to wonder why a top pro used such a tiny amp, but when he plugged in and played they soon realised why!!!!
The distortion and overdrive had to be heard to be believed-it sounded great!!!!!!!![:0][:D][:p]

ActivaV6uk · Post by **ActivaV6uk** » 18 May 2005, 20:16

Mosser well said mate, any one who is seriouse about audio will agree with you. That forum you posted is really good ive been looking for someware like that for ages, the people giving advice are really sensable and know there stuff.
Andy

MW · Post by MW » 18 May 2005, 20:21

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Mosser
You would be pretty stupid to put a nail in place of a fuse that is there to stop you car catching fire, its to protect the wiring and guard against short circuits
<hr height="1" noshade id="quote"></blockquote id="quote">
I know, Mosser, I was just winding you up. Incidentally, did you ever read the story on the Darwin Awards about the two good ol' boys in America who fixed the blown headlamp fuse on their pickup truck with an old rifle bullet that happened to be rattling around in their car?
They got the headlights working UK, but they only managed to cover a couple of hundred yards before the bullet went off. They survived, but the driver won't be having any more children. [:0]

Post by **RichardW** » 18 May 2005, 21:00

My HiFi in the house cost nearly a grand, and I thought that was expensive enough! £2k in a car where you've got to put up with all that engine noise, wind noise, road noise, and non-ideal acoustic environment is (to me) barking - I'd rather spend the 2k on beer and curry[:D]. Clearly Mosser has got too much cash - want to donate some of it to me so I can buy an HDi (with standard ICE)???[;)]

fastandfurryous · Post by **fastandfurryous** » 18 May 2005, 21:08

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RichardW

I'd rather spend the 2k on beer and curry[:D].<hr height="1" noshade id="quote"></blockquote id="quote">
Now THAT'S what I call a good idea! The question is would you die of heart attack or alchohol poisoning?

Mosser · Post by **Mosser** » 18 May 2005, 21:13

The setup was bought at a time in my life when i did have too much money spare, i had a company car, no wife or kids and had about £700 a month spare so i slowly built myself up a killer car hifi system, nowdays, i'm lucky if i have any spare money at all as it is all spent on my 3 children,
And the xantia is a rather quiet car, you get used to the road noise at very low volumes, but luckily it car produce hifi results at volumes louder than the engine when needed, it was also bought at a time when i was spending 8-10 hours a day in my car driving and no much time at home so it didnt make sense to spend the cash of a decent home hifi at the time, even now i still wouldnt spend the money on a decent home setup as the kids are always making a noise, and people watch tv nearly all day, and there isnt any time to sit down and enjoy some music, i would need a music room to be able to use a home system to its fullest, hence the reason for still sticking with my decent car setup