Amp woes

[Heyho]

If you didn't need a ground loop isolator before, you shouldn't need one now.  The seperation of the RCA/power cables is a myth, and need not be done.

Have a look at this, it's pretty comprehensive:

http://www.talkaudio.co.uk/vbb/showthread.php?t=164566

What you describe sounds exactly the same as a problem I had with a cheap and nasty amp.  Follow the above guide, and if possible, try a different amp.

[Uruk Hai]

I don't agree that the separation of RCA/power cables is a myth, before I attempted to install the stereo wiring in my first Golf I read several books and consulted a few fitters about the subject and all the advice I got was the same, run the power and RCA cables down different sides of the car and on top of that run the RCA's the opposite side to the fuel pump. As allready said I would try fitting a suppressor.

[Heyho]

I've yet to see it proved that a whine/interference was the result of RCA cables (AC Voltage) being affected by the power cable (DC voltage), unless the RCA's are faulty and have broken sheilding.

If it was an issue, manufacturers wouldn't risk running airbag triggering circuits near battery leads.

More likely to be caused by poor earths or cheap amps (with poor filtering circuits).

[grimbo]

Right, I think I've gotten to the bottom of it:

http://www.talkaudio.co.uk/vbb/showthread.php?t=61962

Basically I've gubbed my pre-outs by the looks of it. Nice.

My concern now is that I bought the HU online while I was living in Edinburgh last year (back in Dublin now)... Have mailed the pioneer distributors over here - hopefully they can point me to a service center to get it fixed. Have had the unit (DEH P75BT) less than 6 months!

Think I'll upgrade the earths afterwards - pretty sure I read somewhere else that the standard earth through the harness isn't enough.

Will let you know how I get on with pioneer.

[tommk3cab]

yep the HU will be the cause then, i had this happen to my fave ever rockford fosgate headunit, i remember now, one of my door spks were shorting inside the door ( before i took care with wiring!) the RCA outs were first affected, then the HU amp then the HU amp blew all together and the rcs were all that were left!
have you tried another HU yet?

[grimbo]

I plugged a mp3 player directly into my amp and it worked fine. Then I connected teh RCAs up again - savage interference. Disconnected the RCAs from the back of the HU - no interference.

I've dropped the HU into Pioneer to fix. It's only 4 months old - so it should a warranty reapair.

[tommk3cab]

nice one, my rockford was under warranty too but it had to be sent to the US so its still sat in the cupboard, ill get round to it one day.