Got Whine?

[318Joe]

Hep a brother out.

Finally decided to finish out my audio system with a PPI 5 channel amp, using the front 4 channels to actively cross over the fronts.

Pulled the oldschool 2 channel amp I had been using for the sub, ran new wire back to front for the speakers, hooked everything up and...wow. Powering the fronts with something other than the deck pays off.

So I button everything up, hop in and head off to work. Turn on the system and the car fills with the dreaded motorboat and/or alternator whine. Shut off the system until I could run through the checklist today.

Front channels are fed to amp by one rca pair, split in the trunk just before the amp into 4 channels. Speaker wires run in the sill channels on both sides of the car.

deck power and ground are from factory harness

Amp power and ground to battery

So far I have:

Disconnected the rca cables from either the amp or from the head unit, whine stops.

Remove signal splitter at amp - no change

Run new signal wire outside of car - no change

Running dedicated power to battery - no change

run ground to amp ground (-battery term in trunk) - no change



What am I missing here?

Anyone? Bueler?

[318Joe]

Did a little more testing - put an ohm meter between the head unit chassis and the ground on the rca and the readings were all below .4, so the rca's should be properly grounded at the source.

Re-adjusted the gains on the tweets, but that just masks the problem.

Next step is to put a filter on the ignition switch.

[318Joe]

Installed filter on ignition (switched hot) wire and whine reduced but not gone. I guess I'll need one on the constant hot wire as well.

[318Joe]

Soo went to show off the system today and ... nothing. No power. Turned out the noise filter gave out and took the fuse with it. It wasn't doing much anyway.

Instead installed a ground loop isolator in the rca lines - problem solv.. well, masked, anyway. I'd rather not have done it that way but at this point I'll call it a win.