g'day,

This is my first post here. I've recently bought a 2000 TH Magna executive sedan (3l) which is on gas/petrol. This is my second Magna, my first being a 95 TS advance wagon which i killed.

I thought I'd install some decent sound in to the new car as I'd been living with the stock audio of the wagon for years. I have a reasonable amount of experience with home audio, so I thought I should be able to install it myself.. I realize now that I may have been a bit over confident..

So 3 days (and nights) later I've got all the wires in and speakers mounted. The problem is as soon as I reconnect the negative terminal on the battery, the fuse for the amp blows. Rather than describing the set up in text, I'll draw a picture of how it's layed out.
http://users.cyberone.com.au/twistie/carstereo.jpg

The head unit seems to work fine, plays CDs etc.

The fuse near the amplifier (on the red cable) blows first. If I don't put a fuse there, the fuse near the battery blows.

The fuses I had came with my other products. 1 came with the amp, the other came with the cable kit. I believe they're 60 amp, but aren't certain. They looked the same before they blew. I assume they're suitable since they came with the equipment

The fuses blow the instant the negative battery terminal is reconnected.

I've checked for shorts along all 3 power cables (ground, +, remote on). and haven't found any damaged cable or anything.



So my question is, what am I likely to have screwed up?

I'm thinking the ground could be the cause, as I'm not certain that it's location is ok. I sanded back under a bolt on the floor of the boot (under the carpet on the drivers side where it's metal) and attached the supplied copper end thing there.

Another possibility I'm thinking of is the remote on is wired wrong/with the wrong wire. The manual for the HU isn't clear on whether this is suitable.

Of course I've never done this before so I may well be missing something a lot stupider... Can anyone help? I've tried reading around but can't seem to find what I'm doing wrong.

I'd be happy to supply pics or anything if it will help.

Interesting....I would assume even if the remote wire you attached to it was wrong it wouldnt matter, all the remote wire does is "fire up" the amp, like a switch...
check the connections at the amp for no frayed power wire strands or anything.

By no strands, do you mean no strands going off and hitting other wires? The 4 guage wire has a few strands coming off (ive twisted them back on as well as I can), but they're not hitting anything other than the terminal. There's also a bit of exposed wire where it's connected, but not enough to touch any other wires or anything.

Being a total noob at all of this, I'm not sure if having a bad ground could cause this? If not, could you let me know so I stop trying to find a 'better' ground point?

If I don't have the 'remote on' wire connected at all, will the amp stay on or off? Is there any trick I can use to make the amp stay on for testing purposes so I can eliminate this altogether?

The manual for this amp is horrible (it's for everything from a minimal mono amp to high end 5 channel amps). I can't even find what seems to be vital information like how many amps it needs.

By no strands, do you mean no strands going off and hitting other wires? The 4 guage wire has a few strands coming off (ive twisted them back on as well as I can), but they're not hitting anything other than the terminal. There's also a bit of exposed wire where it's connected, but not enough to touch any other wires or anything.

Being a total noob at all of this, I'm not sure if having a bad ground could cause this? If not, could you let me know so I stop trying to find a 'better' ground point?

If I don't have the 'remote on' wire connected at all, will the amp stay on or off? Is there any trick I can use to make the amp stay on for testing purposes so I can eliminate this altogether?

The manual for this amp is horrible (it's for everything from a minimal mono amp to high end 5 channel amps). I can't even find what seems to be vital information like how many amps it needs.
well one would assume, to turn on, it wouldnt draw much current, thus to me a 60A fuse should be fine for it to turn on.

Was the amp working BEFORE you installed it?
Sounds like your ground is fine. bolted to a clean chassis point is ideal.
Stupid question but are you sure you've put + and - in the amp the right way?
And yeah by no strands I mean no strands of wire coming from either the + or - wire and touching the other side. Blowing the fuse means 1) it's drawing way too much, or what I think it is which is 2) a Short

but why is the amp connected to the antenna wire?
im assuming you mean amp remote right?

is there a main fuse next to the battery on the power line?
need to make sure the fuse is rated slightly higher then the fuses on the amp/s
seems the amps pulling too much current or somethings faulty
i would double check over all your wiring making sure no wire is making any contact with metal
also maybe try moving the ground to another part of the boot

is there a main fuse next to the battery on the power line?
need to make sure the fuse is rated slightly higher then the fuses on the amp/s
seems the amps pulling too much current or somethings faulty
i would double check over all your wiring making sure no wire is making any contact with metal
also maybe try moving the ground to another part of the boot
Yes, but even if its a 10A fuse, it's only turning on, and can surely not draw more then 60A on start up.
Try another earth perhaps, but it all goes back to the - terminal anyway, Give it a shot anyhoo

']Yes, but even if its a 10A fuse, it's only turning on, and can surely not draw more then 60A on start up.
Try another earth perhaps, but it all goes back to the - terminal anyway, Give it a shot anyhoo

yeah, well theres something causing a big enough spark to pop the fuses
maybe try another amp to see whether or not its a wiring problem

I put the positive and negative on the amp the wrong way... :nuts: I guess that's what I get for finishing it at 5 in the morning. Hopefully I haven't killed the amp (which is brand new by the way, so I have no idea if it worked but I assume it did). I can't believe all the wiring I did and got that of all things wrong..

I have to wait until tomorrow to buy some more fuses to test again.

Sorry for wasting your time, and thanks a lot for the help.

Good call too, you obviously read my noobishness flawlessly.

I was thinking it was going to be something a lot more complicated. Will let you know how it goes once I get the fuses and test it.

of course if you have damaged the amp you could return it as dead on arrival if you feel a little naughty :liar:

this is the reason i double check everything before putting power to everything but if it makes ya feel any better i blew the crap outta two amps before i learnt .... now was black power :D :D

Yeah wiring them up wrong can damage the input cap that first filters any noise. Not a problem to change if you have, you will just find that no matter what you do, you may get alternator noise through your speakers.

I put the positive and negative on the amp the wrong way... :nuts: I guess that's what I get for finishing it at 5 in the morning. Hopefully I haven't killed the amp (which is brand new by the way, so I have no idea if it worked but I assume it did). I can't believe all the wiring I did and got that of all things wrong..

I have to wait until tomorrow to buy some more fuses to test again.

Sorry for wasting your time, and thanks a lot for the help.

Good call too, you obviously read my noobishness flawlessly.

I was thinking it was going to be something a lot more complicated. Will let you know how it goes once I get the fuses and test it.
Thought so! Doesnt matter man, we all make stupid mistakes, and we learn! good to hear you got it sorted out anyway!

Don't stress man...

Even experienced guys get the simple stuff wrong on occasion.

At least you know it won't happen again! lol

Hell I've done this before.....granted the amp didnt blow a fuse, just didnt turn on....

Seriously who the hell puts a black rubber cover over the positive terminal of a battery and a red one on the negative?
:redface:

Ok, I got a new 60A fuse (which came in a new case connected to 8guage wire, rather than 4guage which the rest of the wire is. I connected the fuse near the battery and connected the amp properly.. but no lights or anything on the amp (or sound).

Could it be my remote antenna wire not turning the amp on? Anyone know if there's a way to turn these amps on without that wire to test?

I'm aware that there's a large possibility that I've blown the amp, I'd just prefer to make sure before starting the return procedure. As 95ts pointed out, it appears it may be DOA ;).

Ok, I got a new 60A fuse (which came in a new case connected to 8guage wire, rather than 4guage which the rest of the wire is. I connected the fuse near the battery and connected the amp properly.. but no lights or anything on the amp (or sound).

Could it be my remote antenna wire not turning the amp on? Anyone know if there's a way to turn these amps on without that wire to test?

I'm aware that there's a large possibility that I've blown the amp, I'd just prefer to make sure before starting the return procedure. As 95ts pointed out, it appears it may be DOA ;).

Do you have a test light or ammeter to check that the remote wire is receiving power from the headunit?

Your headunit may have two 'remote' wires - one being an actual amp remote wire, and the other being for an antenna.

The difference, is the 'antenna' one drops power when the radio is turned off or you select CD player as the source.

So make sure you are using the correct 'remote' wire.

Otherwise, check you have power going to the amp with a test light or preferably an ammeter.

If the wires have power, than you may have fried the amp already.

You can also bridge the power cable to the remote on for the amp. Just need a bit of small wire.

Also as above check the H/U wire , may have antenna and amp on mixed up.

The amp should have its own fuses as well as the ones you installed ,check these.

Looks like a good system all the best.

Once all is well if you have a multi meter check power reading at the amp with its pos and neg. Amp off. but with power running to it.

Then check again but use different earth point(a known good one) for the multi meter. If you have any voltage gain it means your amps earth point is not good.

Eg amp...12.6 volt with good earth and 11v on its earth point you did would show a bad earth.

If there the same no prob.

I tested the antenna wire and it only seems to have 50 milivolts on it (at both ends). This is the case whether it's on CD or radio. So I joined the remote on wire to the +12v coming in to the HU, which is turning on the amp.

Only problem now is that there's no sound coming out :(.

Tried with only the 2 rear speakers connected, and tried getting input from a nintendo DS via a short 8mil - RCA cable. I can't seem to get any sound.

I'm going to try plugging in all the speakers including the subwoofer now to see if it's a "feature" of the amp that it won't work without all speakers.

Is there anything I can do with a multimeter to test?

All of your help and suggestions are much appreciated.

Sounds like you may need to set up the amp.

eg check its in full mode. Not bridged etc check its levels. The knobs on it up to max for starters.

Should work with only one speaker unless that channel is stuffed.

Get it to work with the H/U first then worry about the DS..

What amp is it and how many channel etc..

The knobs on it up to max for starters.

:nuts:

:nuts:
yeah was thinking that too

don't turn your gains up to the max unless you like blowing **** up lol

It's a Cadence FXA5100. I'll just copy the stats from Cadence instead of pretending I know what I'm saying. Note that this is actually more specifications that what's in the manual itself..

5 CHANNEL STEREO POWER AMPLIFIER

SPECIFICATIONS:
* 4 Ohm RMS Power: 4 x 100 Watts @ 13.8 Volts
* 2 Ohm RMS Power: 4 x 150 Watts @ 13.8 Volts
* 4 Ohm Mono RMS Power: 1 x 300 Watts @ 13.8 Volts
* 2 Ohm Mono RMS Power: 1 x 400 Watts @ 13.8 Volts
* Frequency Response: 20Hz - 30kHz
* S/N Ratio: >100 db
* Damping Factor: >200 @ 100Hz
* Minimum THD: <0.05%
* Input Voltage: 200 mV - 8 Volts
* Dimensions: 18" x 11" x 2.75"

FEATURES:
* High Speed Mosfet Power Supply
* Lucite Encapsulated Angled Terminals
* 12 dB Crossover Circuitry
* Fully Adustable Crossover
* Bass Boost Equalization
* High Level OEM Input
* Lucite Encapulated Terminals
* Includes Dashboard Bass Remote Control
* 2 Year Warranty

Speakers are Cadence FXC-6K 6.5 Inch 2-Way Component 75w rms for the front, and Cadence FXS-6934 6x9 55w rms for the back.

Sub is an Audioline ALSL12. I don't know the RMS watts of it.. it says 600w.. but from what I understand, if it doesn't say RMS then it's to be taken lightly.

HU is a Clarion db346mp (has 4 RCA outputs).

I want it to work with the HU, I just tried the DS to eliminate bad input as the problem.

Of course it's still likely that I've screwed up the

I tried with all speakers hooked up, and still silence. I also tried fiddling with all the nobs and switches. I've got it set to 'Full' mode on all the channels, and have all of the dials turned about 45 degrees from their minimums.

Are you sure turning them all up full is a good idea? Won't I blow the crap out of my speakers and/or ears if/when I get it going?

I assume it's still quite likely that I've blown the amp with my original screw-up, even though the green light is coming on?

Are you sure turning them all up full is a good idea? Won't I blow the crap out of my speakers and/or ears if/when I get it going?

I assume it's still quite likely that I've blown the amp with my original screw-up, even though the green light is coming on?

Turning the gains on max is an extremely stupid idea.

There's a few things to check.

Are your RCA's plugged in at the H/U?

Is your remote wire connected to the correct 'remote' wire?

Is the headunit on mute?

Chances are though, you've stuffed the H/U.

I also sure as fck hope you get caught for the 'DOA' bullcrap you're going to try and pull for your screw up

The RCAs are plugged in to the head unit, and to eliminate input into the amp as the problem, I've tried plugging in a nintendo to the amp with a headphone - rca adapter. This eliminates anything to do with the HU (including mute) as the problem, as the amp isn't even connected to it when I do this.

As for the remote on wire, it's connected to the red wire going into the head unit, which is +12v (ACC lead?). The green light on the amp is coming on now, where it wasn't when it was connected to the antenna power like the amp's manual says to (the amp's manual says the antenna should have +12v, mine has next to nothing).

Do amps usually have a switch between RCA and line level inputs? I can't seem to find one so I've been assuming it just takes what it's given.

So it seems I've most likely stuffed the amp. Is there any way to confirm this?

I can't see how it would hurt anyone other than some rich yank.

Yep, send it in to get checked by someone.

It seems you have stuffed it.

With the gain etc i only meant turn up to get volume.....eg is it working?


If the H/D is low no prob but it eliminates another prob, Being low signal.

I never said leave it there as it will cause all sorts of issues.!................

haven't read your recent post yet but just giving reason to my advice.

Back ground I've fitted systems to a lot off cars over the years but with out being there to check the install its hard to offer advice.

Just read the specs


Sounds like a good amp for your needs....

If you have checked all the fuses and it powers, i;d assume the worst!

Amps will work of what you give them ...RCA or low level. but not both at the same time!

cuzman - an RCA is a low level input.

I jumped in the car to take the amp back to have it looked at, and music started playing!! It turns out the head unit's RCA cables are a bit dicky, as is the Nintendo that I used to test or that RCA cable. The head unit is only temporary until I can afford the parts for a Car PC anyway (PCs are my background), so I just bent it in the direction it seems to like and sticky taped it on..

So it's all working now :D. I've only spent 2 minutes tuning it (had other stuff that I should have done over the past few days), but it already sounds great. There's no noticeable noise so far, so hopefully I haven't blown up the filters that Mr Charisma was talking about.

Thanks for all your help and input.

Now I just have to put the car back together.. :D