Audio problem - Where is the AMP?

S

sym

Member
Hey

Previous owner has upgraded the audio system of this 35is.
The system is now having issues. Every now and then random tones are played at full volume. They are not cracks and pops. Rather something from sine wave generator and they last 0.2-3seconds. Frequency is random.

I have been trying to locate the upgraded amp but have not figured out where it is.

There is a sub installed in the load through hatch and its amp is behind the cover in the trunk. It has rca cables coming through the wall between trunk and cabin. The power is taken directly from the battery. Two power cables go from battery to the right side of the trunk. One of them goes to the sub amp. Another one continues to the footwell at the passenger side. Figuring from this the amp must be somewhere at the front but I cant find it. I took off the head unit. Took out the glovebox etc. Nothing. I cant see the power cable there either. Last place where I can see it is at the bottom of the door opening when removing the trim. From there the floor blocks the view and I cant follow it. Nothing under the seats either.

Any idea where to look next or any idea how to troubleshoot? Id prefer not disassembling the whole car :D
 
Is it not where the original 677 DSP amp would be ?

RH rear bulkhead looking into the boot …
 
You mean this? (Image borrowed from internet).
That is where the subwoofer amp is but nothing else.
 

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How do you know there are two amps Sym..? It's possible the sub amp isn't just that and is a multi channel amp firing the rest of the system.
 
Sub amp has only one output. Also, when removing one power cable from the battery sub amp shuts down. When removing the another one most of other speakers go quiet as well. One interesting notice is that the rear mid range speakers still operate after removing power from both aftermarket amps. All of the others are quiet. Also, no more beebs and bobs at this point.

When power is on for the amps the random noises blast at full volume even when the audio/radio is turned off at the head unit.
 
Ok, well sounds like your head unit is still firing the couple of rear speakers.

I guess it's follow the other power lead until you find the amp, could be very small so it's pure uneducated guesswork from this end, you'll just have to remove trim. Best of luck. :thumbsup:
 
Amp noise could be anything really, bad earth, power leads crossing and touching RCA's, linked amps from splitter RCA's, any number of things.
 
sym said:
You mean this? (Image borrowed from internet).
That is where the subwoofer amp is but nothing else.
Click to expand...

The box underneath the ‘ summing interface’ is the 677 amp ..finned aluminium brick :thumbsup:
 
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