Amps/steros and Grounding

Post by **GrahamR** » 20 Dec 2005, 19:42

Hello

Got some kind of weird grounding problem going on with my van.

I have fitted an amplifier, speakers (stero front/rear pairs) and a head unit - very simple install - new lead from battery to amp, amp grounded to bodywork. Lead from battery to head unit. Head unit grounded to bodywork.
RCA leads x2 running down to amp, speaker wires running back up through dash and out to doors.

I am finding that some sort of earthing distortion is occuring- to which the only fix is to earth the negative of the RCA lead to the body

Have checked all wiring many times, and tested all components in different vehicles - all working

Does anyone one if there are any known grounding/earthing/eletrical problems with T25s'v ?

If there are, are there any fixes ?

-Thanks in advance,

Graham

Post by **ROBS T25** » 20 Dec 2005, 19:52

hi there have you tried a different set of rca leads had a similar problem not long ago tried everything and changed them and fine. Also if you are running wires side by side you can get feed back to try splitting all wires up

Post by **GrahamR** » 20 Dec 2005, 20:06

Hello

Thanks, but tried that one.

Have enough spare wires, steros, speakers etc be able to test/replace everything. All individual components in the system all check out OK.

Post by **tweeks** » 21 Dec 2005, 19:45

Hi Graham,

Have you checked that you have a good earth on each of your components with a multimeter on Ohms setting (it should be zero), even a tiny bit of an Ohm will give you a potential difference (voltage) between the earth on the head unit and the earth on the amp. Remember that the earth on your van is used as the reference point for the audio and even a small difference can cause howls and whining. If you can you should use the same earth for all your stereo equipment to prevent this problem.

Post by **HarryMann** » 21 Dec 2005, 20:06

I think Paul might be on the right track - look up 'earth-loops' - depending how it's connected up, you might be earthing at both ends. It's not a matter of the more earths the better (in simple terms). One good earth and the rest of the system should connect them together (failing instructions to the contrary in the guff-sheet)

Post by **GrahamR** » 22 Dec 2005, 00:15

Thanks for the stuff on ground loops

Googled it and came up with:
http://www.jaycar.com.au/images_uploaded/humloop.pdf

The wiring example on the first page matches the wiring in the van.

Will re-wire the head unit tomorrow, and post the results

Thanks for help