I read the DIY post https://www.audiforums.com/m_318162/tm.htmon adding an sub and amp through the stock bose amp. I ran the power wire fine but I can't figure out how to run the RCA's through the bose amp. The DIY is for a 2005 A4. Is there a difference between the 2001.5 S4 and the A4 bose amp because it looks like the open terminals to run the RCA's aren't open. Also the male spades connecters I bought look to big.

Any suggestions?

 

There are no RCA's on the stock amp. What you need is line level inputs on the AMP, or a line level adapter to plug in the RCA's.

 

Where would I acquire one of those?

 

Did you read this part?
10. Cut off the end of one of the RCA cables. Each RCA cable has four wires running through it, two positive and two negative. The outer shield on the RCA ends is the negative, while the inner post is positive.

11. Use the diagram below to see which wires coming off of your stock amp to tap into. Connect the wire taps to the appropriate wires. The ground wire will need to be tapped twice.

I'm pretty sure the pin outs are different.

Any Car audio place will have amps that can do line level, or a line level adapter.
Then there is always www.google.com

 

I already have an amp. Found a line level adapter, but I am not sure how this would work. Would this just tap into the speaker wire?

Sorry for all the questions, never dealt with running a sub and amp through a factory amp before.

 

Yes, you use the speakers for signal, then plug the RCA's into the adapter.

What the adapter does is drop the voltage & wattage of the signal for the amp.

It should come with instructions on how to hook it up.

 

The line level convertors are a cheap way to do it, but the quality kinda sucks. The best way is the JL Audio Cleansweep or Rockford Fosgate makes a similar unit that is supposed to be even better. These run a couple hundred bucks but provide a very clean signal, guess it all comes down to how picky you are on sound quality.

 

Would the line level adapters make the stock bose speakers sound bad, or just effect the added sub?

 

Usually just the sound quality of the sub. The only effect on the stock sound would be if wired incorrectly.

 

Thanks for all the help. I used the line level adapter and it worked well. I don't think the sound quality was compromised at all.

Now i just need to stop the trunk from vibrating so much!