interference, interference interference...
Iv got some much connected on up behind the dash that I "think" somethings causing interference over aux.
Whats there at the moment includes.....
DVD player
Apple TV
Navigation module (Audio connects through second aux plug)
Bluetooth audio module
Video box (setups the correct video signals)
Volts gauge
USB charging outlets
And last but not least, standard aux (Third aux plug)
The bluetooth integration is working without any dramas so the aux connections seem fine, but the navigation implementation Iv made up has the sound veeeeeeery quiet and is a bit "rusky" with any noise that comes through.
I thought it may be the signal was bad, but if it was, the video on the screen would be distorted and failing but that doesnt appear to be an issue. Infact, the video looks absolutely mint!. Looks like something it should have had from factory.
Iv read up on people finding the aux really quiet although I have not found it like that at all. I used my own aux wiring and seems to be fine with a direct connection and also through the bluetooth connection.
But since theres such limited room behind the dash, I think I have my nav setup wrapped around in power lines (I think!) which might be causing interference?
I tested on the TV before and the sound came out fine, I guess Ill need to double check.., or disconnect everything and see if that helps.
I also noticed at full volume on the headunit, and zero volume on the iphone, you can hear a light "click" or slight interference sound, I only hear it when under those conditions, as soon as the headunit it put back to something like 25 and iphone volume is still zero, you no longer hear any sound. But with further research, looks like other have come across similar effects with aux on iphones or while charging. Looks like a good remedy for that is a aux filter to clear out any rubbish and possibly a pre-amplifier setup to give the aux a bit of a boost. Adding a filter can slightly quieten the audio through aux which is why its good to be coupled with a pre-amplifier.
Starting with the aux filter, these are nothing tooooo special to do, just a couple transformers wired inbetween audio lines to filter the extreme high and low bands. Ill chuck up a simple schematic later once I get it all up in eagle pcb design.
But the pre-amplifier audio booster, now thats where things begin to get a bit more tricky. Theres sooooo much that goes into these, the different configurations, gain selections, input voltages, bias ect. Iv ordered some parts which will hopefully come by end of week... really nifty devices.. just seems any decent IC's are a bit on the pricey side (As expected).