I have two 3.5" Speakers in my doors and two 5.5" Speakers in the rear, and I was thinking it might be better to bypass the Bose Amp and directly wire the speakers to the HU (no Aftermarket Amp). But I'm unsure of the pro's and con's (and what kind of wiring do I need to add to make the rears stereo). I have a Pioneer AVIC Z-140BH (which has a MOSFET 50 W x 4 amp built in, I assume this means 50W and 4 channels).

If possible, I'd leave the stock door speakers driven thru the stock amplifier. Or replace them with 6.5's that I could wire directly to the HU. Or just remove them if the 3.5's will make enough sound.

Basically, I'm willing to ditch what's left of my stock system but I don't want to run an aftermarket amp. If it will clean up the sound a bit. I'm not looking for lots of power, just I'd prefer a cleaner and more controlled sound profile.

 

You could just run wires from the HU speaker outputs to 4 speakers, but.... Which interface adapter are you using? Got OnStar?

 

I did exactly what you are asking. I only had to run wires to the Right
Rear(Because they are mono. I used my Service Manual to find how they were connected at the amp and just spliced in there. I left the Bose amp hooked to the two door subs and it works great. The Kenwood I used has 22 watts RMS x4 which was plenty you my app.
I replaced the doors 3.5 with JL, and the 6.5 with Memphis M Class.
I already had the speakers installed. If I was doing the whole thing now I would use a higher sensitivity speaker such as infinity kappa's.
You will still need all the interface connectors to maintain your steering wheel controls, door chimes ect. Dennis on here or any good stereo shop can tell you which ones.

 

I have the PAC-OS2 BOSE and I have OnStar. I'd like to keep OnStar thru the center channel. What I was thinking was splicing off the wires that come out of the stereo (before they go into the PAC-OS2) and running them directly to the 4 speakers so the Bose Amp would only power the 10" woofers and the Center Channel (so OnStar and the Chimes have a speaker to use). For this I'd disconnect the "stock" wiring off the amp and tap into those (except for one rear which I'd have to run cables to). This would minimize the tear up of the car. I only worry that the Center Channel will muddle the sound. But I don't think you can tap into the speaker wiring after the PAC OS2 BOSE because it is processed to be ready for the amp.

If I swap the Woofers out for 6.5's I'd most likely get component, and switch out the 3.5's for the tweeters. I'd need to find good "adapter" plates for the 6.5" components. For this I'd run new speaker wire as I'd have to take the doors apart to put in the components. I hope I can mount the component "box" in the door somewhere. But I'm unlikely to do this as it is a major tear up to the car, and I'm lazy.

I have the current stuff installed, just looking to bypass the amp with minimum work if I can. Sounds like that is what you did, are you happy with the sound?

 

Yes I'm very happy with the setup, sound is crystal clear and has more than enough volume.

 

IF the OS2bose works the way I think it does (notice the big if), then you can do what you want to by cutting the 4 speaker leads going into the OS2 and running them straight to the speakers, but the radio will not auto mute when an onstar call starts, you would have to mute it manually. The center channel would also be 'silent' unless onstar was playing since you took away the radio input to the OS2.

This thread may help you out a bit also.

 

This thread also has some good info regarding making a custom wiring harness for your Vette. Check the bottom of the page for part information... I think I listed everything you need to make it things 'plug and play' between the factory HU and the Bose amp. That way, you could feed RCA level inputs into the Bose amp, and then use the HU speaker wiring output and new speaker wires to the 3.5" door drivers and rear speakers.

If you are looking to re-use the wiring harness between the Bose amp and the new speakers, then you'll probably want a different set of plugs/pins. When I was making adapters to replace the Bose amp with a JBL MS-8, I ended up buying some funky plugs that needed to be modified because they were designed for mounting directly to a circuit card.

 

Radio I think should still mute, as the OS2 Bose has a mute wire that mutes the radio. Not that I actually use OnStar, but I'd like to keep it "functional" I assume if I want to keep the Bose woofers running I'd need to Y the cables (and then I'd still get the center channel unfortunately). But ideally, I think I'd like to go to components. Which would mean I'd send no sound to the Bose amp from the HU. If I go that route, I'm getting an installer to do it. I'm sick of ripping my car apart.