Amp Problem

[jrocket]

Hi all. I just have a quick question that maybe someone will know whats going on.

I have installed two amps into my car, one for the speakers inside and one for the sub in the boot. I have wired the triggers (on signal) on both amps, up to the trigger on the head unit. This should then allow both amps to come on once the stereo is fired up.

If i turn the key ignition to the assessories position i can turn the stereo on and both amps come on as they should. Stereo works fine in this situation.

Okay, well if i go to now start my car, which causes the stereo to flick off and back on, one of my amps goes into Protection mode and wont work. Both amps are different brands. With the engine running i can then turn the head unit off, then straight back on again. After i do this, the amp that was in protection mode, starts to funciton correctly.

This happens everytime i start my car with the stereo already on before i turn the key to the start position. If i turn the head unit off then shut off the car and start it again. Then turn the head unit on, both amps work fine.

It is a bit annoying having to turn the head unit off and on all the time. I was thinking maybe a time delay circuit or something might fix the problem. I am thinking that when i start the car, there must be a bit of a spike in the current going thru the trigger wire to the amps. The cheaper crapper amp seems to not like this.

Can anyone suggest maybe what i should look at. I thought perhaps a Capacitor included in teh circuit there somewhere might take that edge off the power spike fixing the prob?

[Chris Rogers]

you need a relay on the trigger lead.

find a 5 pin relay (jaycar DSE etc.) and wire in this fashion

85 - gnd

86 - radio trigger in

87 - +12 battery (from amp supply) via 5A fuse

30 - amplifers.

give that a burl.

[jrocket]

Sweet thanks mate. Yeah i will have to give this a go. But one of my amps is f!*ked now so i will have to buy a new one. I will do this if i have probs with the new amp.

[TWEBSTAR]

Sweet thanks mate. Yeah i will have to give this a go. But one of my amps is f!*ked now so i will have to buy a new one. I will do this if i have probs with the new amp.

u should check ur wiring becasue it sound like ur earth wire is lose if it still doing it try runing one earth wire for each amp and one power wire 4 each ampbut use 4g wiring 4 earth and power becuase one amp is taking to much power

[Jmaac]

Yep use a relay, you'll loose signal strngth just splicing into it

[jrocket]

Ok Thanks guys. I will have to see if i have any relays kicken round here somewhere. I will have a play around n tell ya how i go.

[Domenico]

This is a very odd problem. Sounds like your HU could be faulty and it's not sending enough current to the amp in order to switch on the power supply. A feature of MOSFET amps is that if they dectect discrepancies in the switching line they shut off to prevent shorting exc.

Try hooking the remote wire up to your accessory line instead. This will solve the problem and will eliminate any delay from the HU signal. (if there is any)

The relay will also work, but would take much more effort to implement than this. You will have to attach the rem wire, power wire and an earth wire/lead to the relay. So you're going to have to hitch power from wires all over the place and run them to the relay. Can be a messy procedure.

I'd reccomend just hooking them up to your acc line. That way your switching power supply won't have any chance of being starved and it won't activate your protection mode.

Try doing this, if it still doesn't work speak to me again as you may have overloaded your ACC line!

Hope that helps!

Edited February 5, 2008 by Domenico

[Jmaac]

U only need a relay for the remote switch. Piggyback second amp in parallel with the first one and ensure your running heavy gauge