Defective amp?

[jmw703 10+ year member]

Ok so i just hooked up my subs and amp in my friends car.. everything works..

The problem is NOT:

The head unit

the subs

the amp and all connections to the amp (power wire, ground, rmt, speaker, rca )

the rca wire.

Meaning the problem lies behind the HU in the wiring which i personally did not do (other than installing the new HU). Im starting to think the local car audio shop which installed my first system did something, because now that i think of it my old system which i bought used had to have the gain cranked in order to be very loud and this was with my old HU with a single 2v pre out. I just didnt know what to expect because the system was used and very old, not very high rms too.

I have a ktp 445 alpine mini amp wired to the HU could that in anyway draw signal or power from my HU since it has no dedicated power/ground wire of its own?

It is directly between the factory harness of my car and the HU.

Or a bad ground connection at the HU? i simply cut the previous connections from the old HU and crimped the new harness to the side of the KTP 445, the ground as well so i did not ground it myself.

Other than what i listed above what could cause this weak signal im getting, im really confused right now.

Any thoughts or suggestions would be greatly appreciated!

 

[akheathen Premium Member]

this is why i suggested taking rca voltage readings to compare. try tapping into the ground connections at both the back of the head unit, and vehicle harness connector. do the same for the main power (yellow) see if you have a voltage drop.