This is not for a G35, but it runs a similar type of OEM radio setup and I know some guys here know their audio well. Just a shot in the dark, but here goes.

I am doing an semi-aftermarket setup which I must keep the OEM head unit. Everything else is aftermarket. The radio is also not in a car it was originally designed for..so mounting the OEM amps/subs/tweets is impossible. Not looking for any award-winning sound setup here...just needs to work and not sound like total poop. The system powers 4 tweeters directly off the head unit's internal Amp and then has line outputs which power 2 amps and 2 mid/low speakers each. 8 speakers total.

Prob is the line outputs. They are low level outputs. I've found the + and - for each line out (there are two separate Line outs, each one is MONO and powers a single amp which powers 2 speakers) and soldered RCA's to them, but when i plug them in, the volume is just too low from the speakers in comparison to the tweeters.

I can't use an LOC because the tweeter speakers are high frequency only.

Any ideas why my volume is so low with my hybrid RCA setup? I think i read that the RCA's are probably high impedance and dropping my signal by a lot? Any other ideas how i can get a good signal from two wires to plug into an aftermarket amp?

I just need a fresh set of eyes to offer a suggestion. Please no comments about getting an aftermarket HU. It would have been done already if I wanted to go that route.

I beleive the G35 Bose setup also uses a LINE out setup that is + and - wire. If so, has anyone ever hooked up an aftermarket amp to the stock HU without using an LOC and how did you do it?

 

What OEM headunit has both speaker-level and line outs?

There's no reason that any volume difference when using line-level inputs shouldn't let your amp bring the level desired by adjusting the gain.

Does the amp have a switch for high/low level that's set to high with low-level inputs?

 

Modern Ford OEM HU's do speaker level and Line outs. It's part of their "audiophile" setups. But the speakers outputs have built in crossovers...so they are all higher frequencies. That's why i cant use a LOC


I've messed with the amp settings, have even tried multiple amps and even used a test bench inside and hooked the RCA's to a home stereo with RCA input. I get music output through all...but need 100% volume to hear anything..and even then it's just not loud enough.

It's almost like i'm losing a lot of signal strenght somewhere.

The radio did work in the factory car it came from perfectly.

 

I would guess that the preout voltage is really low. Maybe try purchasing a line driver that will provide a higher signal to your amps?

 

model number of OEM headunit if possible?

 

I have two radios. Both the same except for the frequencies output from the speakers off the HU. Internal amp power might be different, but for the sake of this discussion they are the same.

1R3F-18C815-AD (the one I prefer to use)
2L1F-18C815-CE

But both radios have the same line outs, and both radios have the same issue with volume being low unless cranked up. Ive been googling this like crazy and would like to solve it so I can get the setup off my bench and into the car.

 

Well, kinda found my answer

Need one of these...or something similar

http://www.logjamelectronics.com/sounlocbosli.html