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Discussion Starter #1
In the 93 convertible 2004 the amp is next to passenger seat. Ive tapped into door and rear speakers to two amps and there is huming crackling and whining noise in the speakers when the new amps are on.

I have a 4awg power wire running close to this going to fused dist block. I have tried different earths and the noise is still there.

Ive tied earthing the cheap autleads line converters to an eathing point in the rear and that made no difference.

Ive taken the distribution block out of equation and the noise is still there.

When i unplug rca cables and the amp is on there is no noise. There is noise whether engine is on or off.

Ive tried a ground loop isolator from loc to amp and it didnt work.

I tried moving the speaker wires away from the 4awg power wire and it made no difference . Unfortunately i cant see a way of running the power wire on the opposite side because i dont want to drill through passenger side fire wall, ive used grommet on passenger side (uk)

Im looking at a line driver but they are expensive and i dont have the confidence they will sort it out.

Thanks in advance for any suggestions

Can anyone help as im about to pack all this work in.
 

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So the input to your amps is coming from the speakers to a High Level Input on the amp? Is this through wires soldered to the speakers then to the amp using an RCA jack?
 

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one of your problems could well be "cheap autleads line converters".

The line converters need to be able to handle higher speaker outputs than most cheap ones are designed for because the speakers you're tying in to are feeding out a higher wattage than the spec of the converters.

Another issue can be that the Saab system is a balanced system, i.e the speaker negative is not just a return path for the signal to the speaker, but actually carries a negative version of the sound to the speaker. (Not the best explanation, but it's from memory the basic idea).

Most people who've had these issues have found that using higher quality LOCs, don't have to be really expensive, (sure I remember reading of prices around $20-$30) and using ground loop isolators on the RCA cables has improved the situation.
 

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Discussion Starter #5
Thanks

Steve!! read so many of your posts hoping you would reply.

You got it in one mate!

Autoleads loc is what im using, today i wires the power amp around the car and the loc rca around the opposite side of the car and the noise was still there.

Here in the uk there is a limit of loc.

The pac and sosche are usually imported.

Ill report...

Any other commercially available LOCs you can recommend
 

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Discussion Starter #6
One other thing to add - would the autoleads loc still caus humming even when the radio is off?
 

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Here in the uk there is a limit of loc.

The pac and sosche are usually imported.

Ill report...

Any other commercially available LOCs you can recommend
DOH!!! Didn't read your status properly, thought you were the other side the pond. If I'd realised you were this side the pond, I'd have quoted a decent LOC price of around £20.

When I had a 2003 Aero, I used this one http://caraudiosecurity.com/shop/product/products_id/3794.html. Much better than the cheap ones from Autoleads.

One other thing to add - would the autoleads loc still caus humming even when the radio is off?
I did find I got humming with the radio off, but this was due to a bad connection for the remote turn on of the aftermarket amp. I initially took a power source from the radio antenna amplifier to turn on the amp, but this was not a clean signal and I ended up with all sorts of pops coming from the speakers, (my sub would even bang just from shutting the car door).

Ensure you have used a good ignition switched source for you amp remote turn on, the auto dimming mirror fuse is a usual choice, and having a good LOC will help.
 

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Discussion Starter #8
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thanks for replies....

Crappy autoleads/halfords loc

I got them free with amp on ebay.

As a result I spent a day messing with all connections and a ground loop isolator to find source of noise.

Massive learning curve on so many fronts

This forum has been really helpful but this wwebsite has essentially taught me all i know about car install www.[B]bcae[/B]1.com/

Do you think a professional would have done this install in a day/?

I mean some guys charge £70 for install. Im just thinking why on earth did i do it..

Hopefully it will all make sense when its all complete
 

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Discussion Starter #9
ICM2 radio signal

Twas indeed a bad line output converter.

In the end i used a cache cloc-d line output and line driver - this means my amps run on very low gain - sounds so clear and brilliant.

Thanks for all your help.

For any noob doing this install - amp1 in the convertible is next to left side passenger arm area below speaker panel - how you remove that panel is beyond me though there was enough room to tap into door speakers.

On a side note, i recently put in an icm2 the problem is the FM signal is now weak, also when i scan for radio stations it just stops at any signal be it a station or not.

Ive found a few threads on this for the saloon but also found that the convertible has an antenna or converter in the passenger door and good not find a fix for this... Any more help would be appreciated.

Once again thanks in advance.
 
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