cabech984

Hi all,

I recently replaced an old Pioneer head unit with an Alpine ILX-W650 and KTA-450 amplifier into my 2007 Z06. I also used a Pac RP5-GM11 interface for SWC. I've been battling a terrible alternator whine that wasn't there before install. Initially, I ran the radio power and ground thru the Pac interface, the amp 12v directly to the terminal on the underhood fuse block, and a clean ground underhood near the fuse block on the frame rail. I have since tried all power grounds through the factory wiring, through the direct lines ran underhood, and even directly to the battery. I'm having zero luck with ridding my system of the alternator whine.

I've separated my wiring as much as possible which seems hard to do considering the amp is mounted directly to the rear of the head unit. I'm not a stranger to automotive electrical, but am by no means a professional aftermarket stereo installer. I feel like I've covered my bases short of cutting everything out and starting over.

I'm also not sure if I'm supposed to have the factory bose amp installed or unplugged while using this setup. My connector on the Pac interface is on the Non-Amplified factory audio side while experiencing this whine. Any help will be much appreciated!

VinceC5

did you bypass the factory amp? Meaning connect all the speakers to the KTA-450? If not, then you are adding too much input into the factory amp without gaining anything. remove the KTA-450 and just go from the head unit to the PAC adapter.

Pb82 Ronin

+1.

Also, that KTA is barely more powerful than a head unit unless you're bridging channels. What kind of sound are you after?

cabech984

Honestly, I wired up the speakers to the amp, and the amp to the stereo. I feel I probably went about this the incorrect way. Once I removed the KTA, everything works great with no whine, popping or anything. Thanks for the suggestion!
I was upgrading the head unit to get something more modern with carplay and bluetooth. As far as my existing speakers, the car currently has some DB Drive(which I've never heard of) 3 way speakers in the doors, and 5 1/4" speakers in the rear. I've never heard of this brand, but I'm figuring a good set of components and some 2 ways in the rear would be better? Bass is virtually nonexistient currently. I'm not looking to add a subwoofer if possible, but Something that is better than stock that will work with the new head unit and existing bose system would be fine? Like I said, I'm no audiophile, but I prefer a clean and full sound coming from my speakers! What would you suggest a good speaker setup would be? I appreciate the help!

VinceC5

factory door speakers are 1 ohm and about 30W, so the factory amp will not be able to properly drive a 4 ohm/100W aftermarket component speaker.

So many options, best to set a budget and then get some ideas to fit. Don't want to give you a $2K idea when you really want to spend $500 or the other way around...

Pb82 Ronin

If you have a 3-way up front, is there an aftermarket amp driving them? Is it run through the Bose amps? If so...that's why they sound "lacking." If you want a "clean and full sound" from your speakers, you won't get that with just door speakers. Especially if the factory 10" woofer was removed (not that those provide mush bass either). You won't be happy without a sub. I promise. A 5 channel amp for the speakers and a small sub (like the JL stealthbox) will get you at least sort of happy. The C6 is a monster to make sound "clean and full."

cabech984

Theres definitely no amp powering these speakers. After thinking about it and doing a little more reading on this forum, I feel that bypassing and adding an aftermarket amp, new speakers and a small sub will definitely be the way to go. I was looking at the JL stealth box and some focal components and 5.25” 2 ways for the speakers.

As far as wiring up an amp and bypassing the factory Bose setup, what is the most routine method to go about that in these cars? Running all new wire? Looping the speaker wires at the Bose amp input/output? I didn’t see much input on that, not sure if I’m even searching with the correct terms!

Pb82 Ronin

First...don't put 2-ways in the rear. Ask me how I know.

Second...ditch everything Bose. Don't integrate with it at all. Run all new speaker wires, RCA's, power/ground. Much easier to install that way and the results will make you MUCH happier. Anything associated with Bose should be thrown into the trash. Again, ask me how I know.

cabech984

What would you suggest instead?

Pb82 Ronin

A standard 5.25" driver. Quality/price is up to you. I have some Focal K2P's back there...but honestly, they're only playing from 200-2K Hz (in my setup), so they're not being asked to do too much. Rear speakers in a C6 are used to augment a lacking front stage, not to provide the stage. Does that make sense? I'm sure even a $40 set of Dayton's would be perfect back there.

cabech984

Thanks for the help and guidance everyone! I'll probably hold off till winter to rewire the audio. I've missed out on enough valuable driving already!

colter

Did you ever install that KTA-450 back in? I've got an Alpine head unit and the KTA-450 to put in. Though someone said they don't put out the amount they are rated for. Though I haven't seen anyone put this amp on a dyno to verify it's not putting out it's rated output of 50Wx4.

brentsz06

Normally these audio sounds are associated with an insufficient ground location/connection, wire. Just my .02