weird audio amp requirement

[shilka99]

I have a question for the audio experts out there.

I was recently playing around with the non-functioning 6-cd stacker in my suv to see if I could fix it. Luckily all it needed was a cleaning and now it works perfectly.
While I was doing this I was playing around with the idea of connecting a 3.5mm auxiliary input. I want to keep the original stereo, and connecting my own aux input should be a lot cheaper than a decent double din unit.

So after a few minutes I found the inputs, and it works. I can flip a switch and the cd stacker signal is bypassed and the aux input plays through the speakers.

But theres a slight problem - the aux volume level is very low, too low to be of much use. I bought an inline amp for headphones and it did increase the volume, but not by much.

So the question is - does anyone know how I can amplify the audio signal from my iphone so that I can match the volume of the other inputs?

[DarcShadow]

I assume you're using the headphone jack from the iphone, might try using the line out option. You'll need a docking station for that though, but the line out is a stronger signal intended for powered speakers. The other option would be to figure out the RMS voltage from the CD stack in order to determine how much amplification of the phone signal you need. From what I can find online headphone jack outputs are around 300mV RMS and most aux inputs are around 1V.

[DarcShadow]

This build it yourself amp might work for you.
http://www.instructables.com/id/The-Opa ... /?ALLSTEPS

[shilka99]

That would be perfect. But the seller is nowhere to be found. I'll keep looking.