How much voltage is too much voltage? My rca pre-amp is 2v, the HU amp pre-amp is 6v.

 

What and where are you measuring to get 6v? Your signal to noise ratio would be inherently higher plus you cannot match your in/out since there is no gain adjustment on the Bose amplifier. I'm guessing you're gonna over drive the input stage on that little Bose amp. Most people just bypass it anyway and run aftermarket door speakers. I suppose you could try it out if you wanted.

 

I'll explain my issue differently since I think you have the technical knowledge to understand. I am using the Metra 7551 wiring harness on my Head Unit. Unfortunately the connectors for the 7551 (rca) have an output of 2v on my headunit, but the other wires that would normally connect to the pac wiring are 6v output. I am not getting a lot of sound out of my speakers, I am not trying to get the loudest car either, I just want the volume where it used to be with my stock HU. The PAC system would be sending the 6v output to the amp anyway, I was asking if I removed the RCA connectors and soldered the 6v output wires to the proper places would it give me the same output of the PAC without having to buy to PAC. I am willing to buy it I just would like to save some time and money. Also with the 2v ouput if I crank the volume to an acceptable level it has horrendous gain distortion.

 

Ok, after looking at both I kind of see what youre saying. The pac unit looks like it has a built in line driver which is how it acheives a high line level signal (output voltage). I believe what youre trying to do is replicate what is done on the Metra 7550 harness. I suppose you could try, im not sure what the results would actually be. If youre set on keeping the 7551 harness I would just get a simple 4 chan line driver.

 

I just looked up prices for the line driver, It's not even worth it to go that route. I''ll probably just get the PAC system. Thanks for the help.

 

The problem isn't signal level, it's signal type. The PAC ROEM-NIS converts from an unbalanced audio signal to a differential balanced one. Sending an unbalanced signal causes the Bose amp to effectively see half the signal as noise, which it attempts to cancel out. Some Bose amps in our cars aren't very effective at cancelling the perceived noise, which allows them to work OK with the 70-7551. So really, it's only Bose's poor build quality that lets any work without a proper adapter.

 

Thanks Wrathernaut, you da man!!