Hello, I thought I should show you how I plan to connect a amplifier to my system without cutting any of the original cables.
I got the schematics from my Honda dealer of the wiring harness at the back of my
non navi system.
This is for a JDM accord, but I think they use the same plug for the TSX.

I first bought from ebay a
Stereo wire harness



and a REVERSE stereo wire harness


I then going to solder together all the wires except the speaker wires and the
ACC. The ACC will be soldered together in a Y-connection to start the amplifiers.
The speaker wires from the reverse harness is going to be connected to a high low signal converter and run RCA cables to the amp.

Here are the audio unit plug schematics:



Good luck, dont burn your fingers with the solder iron :-)
use some crimps if you dont have a solder iron :-)

 

The TSX audio wiring (color codes) are different to the Honda wiring, since the TSX has a factory Amp. The Honda Head Unit uses built-in Amplification instead.

Actually those color codes are exactly the same as my Accord (CL9) audio system


ps. now I know that the tweeters are running off the door speaker wires - so I dont need to remove the honda tweeters since ive cut them off at the HU. Thanks for the diagram.

 

What he's doing is tapping the speaker level outs to the amp, it looks like. It is still better to tap the HU output (pre-amplified).

 

I dont think it is a pre amp out on my euro accord. Its two pugs, the other one is to connnect a cd shifter.

 

Is there a standalone amplifier below the 2 pockets underneath the radio? (behind and slightly below the gearbox)

 

Nope, just the player