I’ve taken apart my wife’s stereo head unit so many times, I think I could do it blindfolded. You remember last time, right? Well, that mod broke.
The FM modulator box I used then was starting to die. All kinds of bad noise was coupling into the head unit, possibly from other FM stations as you’d drive the car around. Just not a good overall solution.
Plus, the charging power supply I used was a linear, which worked fine when she had a small iPod (read: not very power hungry). But since she’s upgraded to an iPhone, a lot more power is required for charging. And stepping down from 12V to 5, well, that’s a lot of drop. Yeah I know, lazy engineering. Should have been a switcher. So you can imagine that the linear popped.
Both good reasons to get in there and fix it right this time.
I decided on a better approach to get a real line input (or “AUX-IN” as they call them) into her factory head unit. A neat company called Jazzy Engineering makes a unique product specifically for Subaru Outbacks for $50. It’s got an RCA right / left connector jack on it.
My wife prefers the gooseneck type iPhone mount/chargers. I found a good one from Belkin for $25 (on Amazon). It has an audio output jack which is 1/8″ audio connector format.
So that presented a challenge. I had to adapt from 1/8″ to RCA R/L. For this, I found an old CD player and tore it apart. Inside, it had a nifty little PCB subassembly with the RCA jack portion all ready to go! It even had a ground loop interrupter circuit on board, consisting of a couple transformers. I just had to add my 1/8″ female connector and I was good to go.