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Location:
Newcastle
Registered:
June 2002
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 Trouble with car amplifier
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Sun, 23 June 2002 03:41
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Hi guys
sorry, this question is not engine related but anyhoo!
Me and my father put some new speakers into my AW11 the other day. But being excited and all we forgot to disconnect the battery. Dad heard some crackling sounds when we installed the second speaker, like something was shorted out.
Now my amplifier wont power up. I checked its 15 amp fuse on the back and it had blown.
So i grabbed another one an shoved it in there and it blew immediately.
So I disconnected the battery, put the 15 amp fuse in and then reconnected the battery, then it blew as well.
I dont know what else to do, it just keep blowing fuses????
I cant get any power to the amp and im pissed off cause that means no base.   
Please if someone who knows stereos, amps and car wiring could lead me in the right direction.
Thanks everyone
martin
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Location:
Brisbane, QLD, Australia
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 03:54
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You arn't using a power wire that is too large are you? It could be letting too much power down it. Try using a lower rated wire for the power.
I also hope you have the amp with a switch on it or to only turn on when you turn on the ignition.
Try taking off the 2nd speaker and trying it again. It is a two channel amp isn't it? You arn't trying to run 1 channel to two speakers are you?
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Location:
Newcastle
Registered:
June 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 05:13
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thanks apollo
my system was installed by Newcastle pro sound, so it should have been installed correctly, with the correct wiring.
bummer, i dont have a switch, it just runs off the ignition.
only my sub runs off the amp the speakers run off the head unit.
thanks for your reply
but i am still without base
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Location:
Newcastle
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 06:55
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G'day,
It sounds like a short.
If you didn't touch any of the wiring on the amp end,then check the wires to the sub aren't cracked or brocken (like where they go under a seat, or through metal).
When did it first pop? was it when you fitted a second sub, or when you recconected the normal speaker to the head deck?
Cheers
Stew
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Location:
Newcastle
Registered:
May 2002
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Location:
Brisbane, QLD, Australia
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 08:19
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| tanman wrote on Sun, 23 June 2002 5:41 PM |
You cannot have wires too big only too small. The amount of current drawn through a power cable is whatever the amp wants to draw. I agree with TOY77 you have a short somewhere. Disconnect your speaker wires and measure the resistance between the terminals, it should be 4 ohms. How many subs are you running and what configuration are they wired in?
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Trust me, I've had a wire too large before.  Kept blowing fuses until I got rid of it.
But yep, break out the multimeter I agree with.
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Location:
Newcastle
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 08:23
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Apollo,
You should have only blown inline fuses with a bigger cable, not fuses on the amp.
Blowing the inline fuse constantly normally means your fuse is too small and to get a bigger one to match the current draw of the amp.
Stew
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 08:35
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If your someone with little knowledge of electronics, I recommmend dissconnecting all speakers from the amp.
Once that is done turn on the amp, if it still blows the fuse it means you have a more terminal problem!
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Location:
Sydney
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 08:40
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check for resitance vrom the positive terminal to the negative erminal of the amp, may be a short inside the amp.. also try disconecting the power cable from the amp and batter and checking to see whether there is any resitance to the shell etc.. your definatly looking for some form of short
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 08:52
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I dont think it would be a short on the supply side of the amp!
If this was so, it would blow the fuse not matter if the ignition was on or not.
I could be wrong, would'nt be the first time.
If the fuse was blowing when the igniton was off, i would suspect the overvoltage/reverse protection diode.
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Location:
Newcastle
Registered:
May 2002
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 09:09
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| tanman wrote on Sun, 23 June 2002 6:58 PM |
Check that the power lead is not short to earth or has a high resistance to the posive batt terminal.
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Dont you mean low resistance! You will always have a high resistance between +V and Gnd.
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Location:
Melbourne
Registered:
June 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 13:29
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There seem to be some SERIOUS misconceptions about electronics and electric circuits here. I will attempt to explain this in a simple and understandable way.
Voltage:
Simply put this is what is 'supplied' by a source. In this case it is the battery (or alternator). It is roughly 12V (the varying speed of the alternator and varying loads on the cars electrical system means it usually fluctuates between about 11.5 and 14.5V)
So you 'give' 12V to the amplifier (the load).
Current:
This is determined by what the 'load' wants. In this case the amplifier. it will 'draw' whatever current it needs regardless of what size cable it is connected with. So a bigger wire WILL NOT deliver 'too much' current. If a wire that is too small it will simply heat up if a large current is drawn - this is how a light bulb works and how a fuse works.
A light bulb has a large current go through a small wire which makes it very hot and therfore gives light! A fuse is similar, when a current is TOO large the fuse gets too hot and melts (blows) whichs breaks the circuit.
That is why it is imperative that a power cable is properly fused, if it shorts a HUGE current will flow and it will literally light up! This causes fires and all sorts of other nastyness.
Power:
Is simply a relationship between voltage and current.
Power = Voltage x Current (P=VI)
So if an amplifier 'uses' 600W (VERY different to it's audio output due to efficiency etc, and will change depending on volume etc) and the source delivers 12V it will draw a current of 50Amps - regardless of cable size. If this exceeds the fuse's rating it will blow.
Resistance:
Resistance will not affect current. It will however drop voltage. If you measure the voltage across your battery and again across your amp you will find that it has dropped - sometimes by as much as 1V! This is because the power cable has a 'resistance'. A smaller cable will have greater resistance and a larger cable less - hence less of a voltage drop!
Therefore it is ALWAYS better to have a larger cable for less resistance.
A small cable will cause a greater drop in voltage which can damage equipment. Most amps will shut down in an 'under-voltage' situation.
How does this all relate?
The fuse on the amp will blow for one reason:
Too greater current flows through it.
Why this has happened is what we want to know.
NEVER replace a fuse without knowing what blew it.
In this case it could be a couple of things:
A.
The fuse is too small for the amp. Unlikely as this usually occurs while playing music and here it occurs straight away.
B.
There is a short in the system. A short happens when the source (battery) is presented with little or no resistance (Load) like when the power cable touches the body and the circuit is through the power cable and back to the battery through the body. This will allow a HUGE current to flow and should blow the fuse.
The main fuse should blow in this situation.
Check ALL the power cable for any possible short. Also check polarity (that +ve is in +ve and vice versa).
If it was crackling when you wire up the speakers it means that the amp was powered up, eg ignition was on - not good! However if the speaker wire was grounded (touched the body) it may have blown the amp fuse when the amp was on. So check all that too.
This sort of thing is really hard to diagnose remotely, especially without knowing what amp, fuse ratings, install etc. My best advice is to VERY CAREFULLY (and with the battery disconnected) check ALL wiring and go from there. Also check the amp manuals for the fuse rating you should be using.
What everyone else is saying is true, if you don't really know what you're doing take it back to the guys that installed it for you and let them check it out. Better safe than sorry! The last thing you want is to return to your car to find it on fire due to faulty audio wiring... (trust me i've seen it happen)
As i said i tried to explain all of this in a simple way so some things aren't completely technically correct but should be ok in this situation.
If anyone wants to know more, or in more detail, just ask. I can explain it all the way down to coulombs, potential difference and electron flow if you like!
Cheers,
Robin.
robinjp@mac.com
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Location:
Sydney
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 23 June 2002 14:26
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good stuff rob having a bigger cable will only do good (cost aside )the prob is either with the wiring to the sub (a short *read above*  ), the sub might be stuffed causing a short, or your amp has gone to thatbig woofer is the sky...
btw i had the same prob it was the amp go have a sniff of it see it it smells strong
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Location:
Sydney
Registered:
May 2002
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 Re: Trouble with car amplifier
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Mon, 24 June 2002 01:16
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I suspect you have blown the amp. To be absolutely sure,disconnect everything except power and earth. Power on, if fuse blows,internal power supply or output stage transistors have blown.  If this is the case take it to a good TV/Radio repair shop for a quote on repairs and/or shout yourself a new amp, get an electronics wizz to help you hook it up, there could be a short lurking (you don't want to blow it again.)
Pedro
*****
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Trouble with car amplifier
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Mon, 24 June 2002 08:28
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Resistance will not affect current. This is not true at all.
If your an electronics tech Robin you should know I = V/R. Which means Currnet = Volts divided by Resistance.
Less resistance = more current. More resistance = less current.
Dont get me wrong,I'm not having a go at you! Its just that you said other people are confusing things, then you say that resistance will not affect current!
Sorry just had to point that out.
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Location:
Melbourne
Registered:
June 2002
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Re: Trouble with car amplifier
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Mon, 24 June 2002 08:40
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Sorry Cool1, i appear to have confused people!!!
Ok, what i meant was that the current will not change across a load, however the voltage will drop, going with Kirchoff's laws. Eg, if you put 10 resistors in a row and measure the current at one end and the current at the other you will find it is the same.
You are quite right in saying that lower resistance will allow more current to flow - hence a short circuit!
This is exactly what i was worried about! It is hard to write things in a way everyone will understand while being completely technically correct!
Again, sorry if i confused anyone! (my excuse is it was late and my head hurt...)
If anyone really wants to understand what is going on in a simpleish way i suggest you go out and pick up a Yr 11 Physics text book - it will tell you all you need to know!
(with the added bonus that it has been proof read many times - instead of not at all! )
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Location:
Newcastle
Registered:
June 2002
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Re: Trouble with car amplifier
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Thu, 27 June 2002 01:21
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Thanks for all your help guys
just so that everyone knows, this is my setup:
1 alpine 4x45 head unit, running 2 x dash mounted 4" clarion speakers. also running 2 x pillar mounted 3.5" JBL speakers with 2.5 cm tweeters.
1 x blaupunkt 2 channel amp, http://www.bosch.com.au/productcatalogue/scs1/prod ucts/Mpa2.htm , running 1 x 10" clarion subwoofer in an enclosure.
All installed by newcastle pro sound ( and was running fine)except for the 3.5 inch JBL's. This is what my father and I put in the other day.
When we put the second JBL into the pillar near the drivers head we heard a crackling sound (possibly due to the ignition
being on, I know, we f..ked up) when the speaker touched the pillar.
All the guys who said the amp has shorted out, I think this is the case.
NOW for the fun part, I dont know enough about electronics to try and fix it myself and I dont have enough time on my hands.
I shall take it to Newcastle Pro sound and:
A: tell them my story about our dodgy installation of the JBL's, and the ignition being on, and the crackling sound.
B: Tell them that I installed some new speakers and ever since then I have had no base. (let them work it out)
or does anyone know what I should say to them? DONT forget all these items were purchased and installed not to long ago, so its all still under warranty
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Location:
Newcastle
Registered:
May 2002
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Re: Trouble with car amplifier
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Thu, 27 June 2002 06:54
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Remove all evidence of you speaker installation and take it back to them under warranty.
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Location:
Newcastle
Registered:
June 2002
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Re: Trouble with car amplifier
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Thu, 27 June 2002 23:27
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Good Idea Tanman
 ill see how I go. Ill let everyone know how things end up.
A big thanks to everyone for the detailed responses
martin
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Location:
Newcastle
Registered:
June 2002
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Re: Trouble with car amplifier
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Sat, 29 June 2002 20:10
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Well guys
shes booked in. Cant wait to have the base back. Sounds so tinny at the moment.  they can sort it out.  also forgive me for being so dumb with car audio
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 30 June 2002 01:24
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Your not dummb, just not so knowledgeable with electronics!
Good luck with the amp.
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Location:
Melbourne
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 30 June 2002 05:13
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Dont know if anything i am about to say has been said before in this thread (READ: i could not be stuffed reading it all) hear goes anyway.
1. Check your current load 1st, you will find that you will keep blowing fuses if only you are pulling to much current. This could happen when the amp is needing a 12v supply and only getting 9v. Hence the amp will pull more amps to make up the difference and you will blow the fuses.
2. Check you got a fuse connected to your battery for the power feed to the amp. Make sure you do.
3. Your amp should be triggred by a remote wire from the deck, which will activate the amp when the deck powers up. Unless you do not want to run the amp all the time. Then you will need a switch.
4. You said your system was installed professionaly, dont know these installers or the work they do so i am not knocking them, it just i have seen some dodgy shit in my time from people who call them selves professionals. YOU KNOW WHO YOUS ARE.
Good luck with your problem and hope you fix it if you havn't already.
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Location:
Melbourne
Registered:
May 2002
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Re: Trouble with car amplifier
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Sun, 30 June 2002 05:19
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Just read the bottom part.
If you are suffering from a lack of bass in you system. Check that your speakers are not wired out of phase. i.e the polarities from the deck match the polarties on the speakers, so one speaker is not poping out when the other is moving in. This will cause a cancellation out of the sound waves in the lower frequencies, its kinda like not seperating the front of your speaker from the back, it wiil have the same effect.
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Location:
Newcastle
Registered:
June 2002
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Re: Trouble with car amplifier
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Fri, 19 July 2002 23:41
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Guys
the car was booked in at Newcastle Pro Sound to repair the faulty amp. Instead of repairing it, or doing whatever, they just ripped it out and replaced it with this foreign model.
THIS IS MY ORIGINAL AMP
Max power into 4 ohms,
2 x 80 / 1 x 180 W
RMS power into 4 ohms,
2 x 30 W + 1 x 90 W
Channels 2 / 1
Frequency response 20 - 50,000 Hz
Signal / noise ratio dB/A > 90
Variable sensitivity 0.3 - 5 V
2 ohm stability (stereo operation)
Switchable low-pass filter 75 / 100 Hz
THIS IS THE ONE THEY REPLACED IT WITH
2/1-channel output stage
Max. power 2 x 100 W / 1 x 320 W
RMS power 2 x 50 W / 1 x 160 W
Bridging mode: 2/1 Channels
Low-pass variable
High-pass switchable
Bass Boost 0/9/18 dB switchable
Dimensions: 218 x 57 x 250 mm (W x H x D)
I am very pleased with the new amp, creates lovely punchy bass, or with a quick adjustment, low and deep killer bass 
Once again my AW11 pumps out audio, hopefully it will stay that way 
I would also like to thank Clarion for making such high quality woofers
this is what ive got, which the above amp runs
it really rocks the AW11
,from behind the passenger seat I had no Idea that woofers, even a single 10 inch, did so much to improve the sound
thanx guys
later
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