Thud when switching on and off

[Neil VR6 0]

I've recently installed my old system into my new trolley. It sounds ace but it thuds when you turn it on. If you don't turn down the volume before switching it off it thuds then too.

 

The components:

 

Alpine MRD M500

Alpine MRV T420

Diamond Audio CM3 sub

Genesis Audiophile comps

Alpine CDA 7873 h/u

 

All the kit bar the components were in my old Corrado and there was no thud and I can't imagine the new speakers are the origin of the problem. All the cabling is good quality: 4 gu for the power (before the dizzy block), Directed RCA's, good quality speaker cable etc. All connectors have been properly crimped on. The power supply must be good as the voltmeter on the amp shows 14.8v for most of the time.

 

Any ideas?

[MickeyT 0]

Sounds like your having similar problems to me. I recently changed my Kenwood headunit with another. Literally a plug and play affair as the connections at the back are the same.

 

Now when I start the engine with the stereo already playing I get a thud through the speakers!

 

Doesn't sound too healthy does it!!

 

I can't understand it either as all my wiring is the same

[Neil VR6 0]

I've got a feeling it's something to do with the remote. I've tapped into the lead on the ISO which says somethign like "ignition" on it. I presumed this was the remote wire. It turns the amps on and off OK. I've done some research on talkaudio.com but can't see what I've done wrong.

[_Monkey 0]

How have you routed your wires?

 

If the RCAs are right next to the power cable, that'll cause interference similar to what you're describing. Might also be worth getting a ground loop isolator for your RCAs.

[Neil VR6 0]

Power and one speaker wire down one side and RCA's and the other speaker wire down the driver's side. What's a ground loop isolator?

[selbekk 0]

it's probably the earth to either your amps or your head unit.

[_Monkey 0]

You should really have your power completely seperate from all the rest, cos it can effect it.

 

A ground loop isolator is basically a box you put your rca's through to stop all kinds of ground based interference.

[jedi-knight83 0]

more than likely the earth. i had the same problem when i installed my sub / amp combo and was told to find a better earthing point. that solved my problem

 

also though the ignition thing you got the remote feed from is wrong i think. ignition in on the HU is so the HU only works when the ignition is on. if you have got a feed from that then the amp will be turning on as soon as you switch the ignition on even if the HU is off. your HU will have a dedicated IGN feed and you should use that instead!

[Neil VR6 0]

more than likely the earth. i had the same problem when i installed my sub / amp combo and was told to find a better earthing point. that solved my problem

 

also though the ignition thing you got the remote feed from is wrong i think. ignition in on the HU is so the HU only works when the ignition is on. if you have got a feed from that then the amp will be turning on as soon as you switch the ignition on even if the HU is off. your HU will have a dedicated IGN feed and you should use that instead!

 

I'll defo look at the earth. Interesting point about the ignition feed on the ISO....I'll see if the amps power up when the face off is detached from the h/u. I'm at a bit of a loss with regard to which wire to splice into in that case. :?

[Kevin Bacon 5]

Alpines have a blue/white wire with "remote" written on a blue label..... and not to be confused with the electric aerial trigger wire, otherwise the amp will switch off when you turn the tuner off to put a CD in.

 

Thudding is the Amp's 'soft on' circuit either being over whelmed by an erraneous signal, or not working. Poor earths can cause it as can iffy signals going into the remote on connection.

 

And starting the engine with the stereo powered up is not a good idea as the load induction relay will power down accessory circuits anyway, some ICE doesn't like that at all. Start the engine, then start the ICE.

 

14.8V is way too much, did you mean 13.8V?

[Neil VR6 0]

No, 14.8v! I was also surprised! Alpine quotes their amps power at 12 and 14.4v so I can't imagine that 0.4v difference is going to do much harm?

 

I definately haven't used the electric ariel wire as that's clearly labelled.

 

I think I'd best sort out the earth before anything else, eliminate that first of all.

 

It's a pain on the 200SX as you have to take the dash apart to get to the HU, great for security but not for fiddling!

[selbekk 0]

I had to pretty much disassemble the whole mid section of the dash to re-earth my head unit to the chassis underneath the gear surround. I've now done this (removing the mid section incl. all acc., the instrument panel surround and glove box) three or four times, and last time it took me about half an hour putting everything together. Not bad, when I spent about four hours taking everything apart the first time.

 

My electrics are hopeless.

[Supercharged 2]

Measure across the battery terminals, most likely the voltage guage on the amp is inaccurate...

[Neil VR6 0]

Had a faff with it last night and the ingnition wire on the ISO connector is acting at the remote. Duh! I'll make amends at the weekend and take it from there.

[ReekieVR 0]

Did you resolve this Neil ? I am having the same problem.

[Deluk 0]

running a real live from the batt for you hu is also a good thing to do 5amp cable will do it