Small audio mod for stock radio

[Guas]

I'm sure this has been posted before but this is what I'm currently running in my car. Its a adapter that plugs into the EQ port on the back of the stock radio and overrides the input for the radio. I believe that the audio input should be grounded to the output and main radio harness. There is a hum when there is nothing playing at high volumes which I believe is caused by the floating ground. I also think that there should be a capacitor or resistor to prevent a spike when connecting the aux cord. However I'm no electrical engineer so feel free to add some input. I'm also currently working on a switch to change from aux to regular radio. I also believe I used a 8 pin midi connector from a e-waste store.





Simple wiring diagram:

[Jinnai]

That's really cool dude, I'm watching this!

[Guas]

Unfortunately I cant continue with this project because my stock radio kicked the bucket. I'm trying to fix my radio but I don't know much about audio repair.

[Jinnai]

Thanks for the update! Do you think it kicked the bucket because of the mod? I've been worried about injecting too much current into a pre-amp signal, but never had any proof that it was the cause

[ShiRen]

So, yeah this would result in sending a headphone out signal into a line input, but that's usually not very dangerous. Headphone out usually operates within the range of line voltage, it just has the capacity to drive high impedance devices, which a line input would be the opposite of since line signals must make it to an amplifier with as little degradation as possible. Keep in mind a line signal can be something like minute voltage fluctuations from a stylus riding across a disc with microscopic bumps. Headphone and line out are absolutely not the same and headphone out can definitely create some spicy signals. That's highly unlikely if you are using a USBC or lightning dongle on your phone, they're usually almost exactly within line spec, but if you brought your big smelly headphone amp into your car then yeah, that might be a bit too hot.