So I just purchased a 2013 G37 with Bose/no navigation. I am getting ready to replace all the Bose speakers and the amplifier with my own equipment. My question is do I run from the Bose head unit to the high level input of my Helix .3 dsp or do attach RCA's to the output wires from the head unit and use the low level input of my dsp? Correct me if Im wrong but the signal coming out of the head unit is a low level/balanced signal. Can my dsp accept a balanced signal? Non of the amplifiers that Im installing accept a balanced signal. Any help in this matter would be greatly appreciated.

 

Pretty sure the signals coming from the Bose head unit are "line level", like the output from the headphone jack of your phone or whatever. The Bose amp is just that: an amp with line inputs and speaker outputs. Looks like the Helix gives you the option of a standard (line level) inputs and high level inputs - like AFTER the amp (??). Signal from Bose head is not "balanced" as far as I know, it's just + and -. But I'm not sure how many channels it spits out.

Study here:
https://www.nicoclub.com/service-man...F2013%2FAV.pdf
(download that manual from link below the window). You want the section called "Bose No Nav"...

 

I can't confirm the 2013 head unit but the outputs from my 2008 were balanced line level.

 

Interesting! So it's two conductors in a shield style balanced. So I would guess an RCA connector for the +/- and ground the shield to the amp or dsp?

Looking at that manual, the head unit has 4 outputs (4 doors) and here's what I think are the amp input signal wire colors, at the amp:
Front RH - R+, G-
Front LH - P+, L-
Rear RH - BR+, Y-
Rear LH - V+, SB-

 

I used a Rockford Fosgate 360.2 which accepts balanced signals.

I've read several thoughts on where to ground the shield. The one thing that sticks in my mind is in WWII the radio operators would ground only one side of the shield otherwise they would get ground loops. They would ground the preamp side farthest away from the amp otherwise the shield would be like an antenna. Not sure it has any bearing on car audio but its worked for me so far

 

That sounds right. Some high-end audio gear uses that scheme too. The shield is meant to act like an extension of the radio chassis - as if the wire never leaves the metal box which "shields" it from induced interference by other equipment. Not sure in this application which end is meant to be connected and which is not, because both the head unit and amp should have their own robust connections to ground. So "extending" the shield from one end or the other ... I don't know. However, in this FSM it appears the shield IS connected on both ends of this run so, who knows? Floating the amp (or DSP) side of the shield would be worth trying. If clean, you're done. If noisy, try connecting it.