As many of you may have noticed, yesterday i wasnt on the forum.

Was out getting someone to wire in my girlfriends sounds system in her car. But there is a problem....

Basically there is 2 rca's running to the rear to connect into 3 amps. One rca for the speakers and one for the subwoofer.

Now forget the other amps for the moment. We only got as far as the speakers amp.

Its a dub amp and when we wired it all up and it lit up there was no sound but a "pwr/prot" warning light. So it was protecting itself against a power overload??

Anyways, managed to get the amp working but only on the radio mode of the head unit. Anything else (dvd, aux etc) would trigger the protection circuit.

Increasing the volume on the headunit or the amp would also trigger this.

Anyone, any ideas as to why this is happening? No problems with the headunit before this and i run the same headunit connected to an amp aswell, without any problems.

Ross

Has the amp or headunit got a switch for different level rca inputs, sounds like the head unit is giving the amp the wrong level.

Well here is the thing... It has high and low level input settings.

The low level is where the rca's are plugged in just now. The high level requires some kinda adaptor.

Ross

have you got the remote power on cable plugged into the amp or is there a manual switch somewhere?

the rca are delivering a higher voltage level than the amp accepts (that's why at higher levels it protects itself)

I had the same problem with my first carpc, I solved it by changing the two amps, because the one that was powering the subs had a broader input band

Oh right. We have a Star Sound Jackslammer amp aswell, which was supposed to run the sub, but we might wire it in a way that it gives power to the speakers and the other amp gives power to the sub, or will that still not work because of the RCA output?

Ross

If it's a decent headunit, which I'm sure it is, you might be able to change the voltage output of the RCA's.

Or you could try turning off the internal amp in the headunit.

not all the amps have the same tollerance in the rca so I'd give it a try and see if it works with the other one

sounds like you need to explain to him how you could do this

run a voltage meter on your rca and se what the voltage is [more than likely 2v and under which is ok on any decent amp] than check you have a live remote turn on wire in all mode’s[i.e. cd,tuner,aux]sounds like you may have two from your h u, one might only work for the aerial amp hence the radio etc, also check the power cable isn’t warm i.e. to much load, last of all you must have a good earth other than that make sure you haven’t earthed out a speaker, all these symptoms can cause your fault, other than that, your amps are toast matey. Hope this helps

We've tested the amp with it just connected to the headunit and above a certain voltage its just going into protection. Maybe need to test the RCA's right enough and see what they putting out. Thing is tho, (just remembered) that even when the volume on the heaunit is 1, if you try and amp it up with the amp's volume control, it just goes into protection again? Is this another sign that the RCA's are kicking out too much voltage?

Ross

How am I supposed to know how to work his headunit?

not really in my experience if lets say you had a one off head unit i.e. a Rockford fosgate kicking out 8 volts pre out you would get distortion up to all most full kick then maybe protection, after the list I wrote you if all correct wiring wise you gotta think the amps got faults,But a speaker short will deffo cause this tho instantly, with so many possibilities to the cause, you really will have to do a full system check

We are gonna try a different amp sunday/tuesday and see if we can find out if its the amp. I suspect it is.

Ross

just a tip.....are you sure it's not the amp's ground?

But that would cause the amp to be dodgy at all points?

Ross

Not necessarily Ross, a shit earth is the most common fault on ICE installs. Easy to check.

Well... we drilled a hole in the floorpan, and put a bolt in and used that as an earth.

Ross

Good show, did you make sure you removed all the paint and primer so it had a good bare metal contact?

Yeah took a piece of sand paper to it.

Ross

OK, and the power is from the battery yes?

Yeh from the battery with 4 gauge.

Ross

Hmmm, maybe it's a fooked amp then.

Thats what we are thinking. U an audio installer? any DUB amps?

Ross

I'll fit anything.

However we're not an Audiobahn agent I'm afraid.

U in glasgow anytime soon dude?

Ross

I don't think so, but to be honest I haven't looked at next weeks fitting diary yet...

Any chance you could drop me a line if your gonna be near so you can take a look?

Ross

Of course.

RMA'd two audiobahn amps straight out of the box. Not very impressed. Vibe BB2's still going fine after 4 yrs of use/abuse