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Discussion Starter #1
I am not that electronically challenged, I love doing things to my car, always doing SOMETHING, haha.

I still have my JL 300/4 Amp sitting in the garage and I am really wanting to replace the factory ampifier in my 06 Speed6.

How exactly can this be done. What are the downsides to doing this?

I am not too familiar with the OEM amp, but I do know, it has inputs AND outputs, which is not what we see on a aftermarket amp.

Help is appreicated, I already got my Kappa components in, but doesn't make a big dif with the factory Bose amp.

Thanks in advance,
Pathik
 

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You will def notice a difference if you slide the jl in there. Do it, it's not that difficult at all.
You can follow the pinned info at the top of this forum for the color coding on the stock wiring harness under the seat. Just unplug the stock amp under the pass seat and slide the 300.4 in there, patching it in where nessecary.
Because they are seperate power, amp and speaker, I believe the stock sub set up can still be utilized until you decide to upgrade (which we probably be about a week :D ).
Good luck.
 

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I found it much easier to tie into the factory preouts at the headunit, then running rca's from there. I put my amp in the trunk and ran all new speaker wire from there.
Good luck
 

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I found it much easier to tie into the factory preouts at the headunit, then running rca's from there. I put my amp in the trunk and ran all new speaker wire from there.
Good luck
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I'm almost positive there aren't preamp outputs on the factory headunit. Or at least not on the bose. I'll find out for sure as I'm replacing all the speakers and the amp next week.
 

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I'm almost positive there aren't preamp outputs on the factory headunit. Or at least not on the bose. I'll find out for sure as I'm replacing all the speakers and the amp next week.
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THere are 4 pre outs on the bose head unit that feed in to the bose amp. You have to splice female rca's into them and run rca's from there. Thats how I did mine anyway. I figured the signel would be better at the headunit then at the amp because it didnt have to travel thru all that wire and plugs before it got to the amp.
 

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I'm almost positive there aren't preamp outputs on the factory headunit. Or at least not on the bose. I'll find out for sure as I'm replacing all the speakers and the amp next week.
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The Bose has pre-amp outs, the non-Bose doesn't.
 

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Are you guys just alking about a low level output? I don't recall RCA outs on the back of the BOSE head unit. I spliced some female rca plugs into the bose wiring harness that goes into the amp under the passenger seat.
 

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like gspot mentioned, the bose OEM HU outputs low level signals. **EDIT** you'll need to splice in your own RCA <strike>female</strike> male ends. a pretty easy task.

splicing behind the HU or before the bose amp under the seat is neither here nor there; it's the same point electrically.
 

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Discussion Starter #9
So what is the downside, or difference in splicing behind the headunit (wires that lead to the amp), and in splicing at the amp (inputs from the HU)?

I am not that electronically challenged. So I would imagin I would completley cut off the harness behind the HU (or at the amp) and wire in my own RCA's (one pair). I'm free almost all week and would like to get this done soon, so Ican begine my fiberglassing on the Speed.

Thanksfor the help guys.
 

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Splicing at the HU will require you to run a new set of interconnects with RCA connectors between the HU and the amp location. Splicing at the amp will allow you to use the factory wiring harness and avoid running the new set of cables. Theoretically, splicing at the HU will give a slightly cleaner signal, as most good quality pre-amp cables use high quality conductors, and the presence of a ground (black) next to the signal line for most of the run will help to dampen some electomagnetic interference (EMI). If you wanted to go further you can get shielded interconnects (they have a grounded metal braid around the signal conductor). At very high freq this shield can cause attentuation but it won't affect anything at audio frequencies.

There are two ways of splicing at the amp as well:
1. You can get a long enough set of interconnects and cut one end off. Hardwire this cut end to the wires coming out of the HU. Now you have a HU with really long cables with male RCAs on the end to go into the amp. This reduces un-neccessary mechanical connections but means that taking out the HU will require cutting the interconnects.
2. Wire female RCA connectors to the wires on the back of the HU. Get a good set of long interconnects (male RCAs on both ends) and connect up. If you ever remove the HU it will be easy to disconnect the interconnects, but you'll have an extra set of mechanical connections.

Realistically? In a car environment I doubt the difference would be audbile. Personally I'd save the effort and do it at the amp. You'e going to have enough things to do as it is.

Get some short, good quality interconnects, cut off one end, hardwire (solder) the cut ends to the appropriate wires in the harness, plug the other end with the male RCAs directly into the amp. No need for more mechanical connections than that.


Others may counsel otherwise of course. Just what I would do if it was my car.
 

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Discussion Starter #11
Exactly what I planned on doing.

Another thought before I take my car apart today...

I want to leave the bose amp in the same spot, so it can power the Bose subwoofer. So, all I have to do, if I am not mistaken is cut off the 16 wires (8 for speaker inputs, 8 for pre-amp outputs coming from HU to Bose amp). From there, run speaker wires to the JL amp in the trunk, and solder on RCA connectors and run RCA's to the JL as well.

And of couse, run my remote/signal wire either to the Bose amp (tap existing wire) or run to another source, run my battery and ground cables.

Please correct me if I am wrong or missing something :)
Thanks to all for their help and valuable inputs.

-Pathik
 

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I may not be able to completely help, but I am certain that the underseat amp does not power the sub. The bose sub in the trunk has its own amp attached directly to it.
I believe the signal simply passes through the under seat sub as a low level signal.
I may be wrong, but I do not believe the underseat amp adds any eq or crossover to the signal. That is all done at the amp in the trunk. If this is in fact the case you can simply wire the sub signal by bypassing the stock harness.
I hope this helped. Good luck
 

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You cannot just cut out the wires, you will need to splice into them. I just redid the stereo in mine this weekend and noticed that there are 4 channels in and 5 out. So the feed for the sub amp is pulled from either the front or rear speaker input from the headunit. So, if you want to pass it through the Bose amp, you will need to leave the appropriate wires in the harness, or like Cherryspeed said, you could probably splice the signal wire to the sub to either the front or rear channel from the head unit and completely remove the amp.
 

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Discussion Starter #14
So,

Instead of cutting, I just tap the wires?

I've got the wiring diagrams, colors, etc. I just bought my 2 male to female adapters and got a harness made up to run speaker wires from the bose amp to my JL amp. Do I splice both the speaker inputs and bose pre-amp outputs at the amp harness?
 

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Yeah, if you are intending on running the factory sub signal through the amp, which isn't necessary, you should tap in instead of cutting the wire out of the harness. You will only need to cut the speaker wire if you intend on using the factory speaker wires which I'm assuming you are. In my setup, I spliced the rca's in at the amp. The sound quality is good, I did it there as I contemplated adding a 3sixty down the road. For the speakers, I ran new wire from the amp to the door jambs and spliced in there so I was using as little factory wiring as possible. I was going to completely run new wiring, but that was going to be too much of a hassle and would require drilling.
 

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Discussion Starter #16
Sweet, so I tap for the RCA's (8 wires) and cut off the 8 speaker wires leading to the door jams and run my own speaker wires?
 

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That is correct. I also found that if you're limber enough, you have just enough room to tap into the wiring harness under the passenger seat without removing it. Just slide it all the way forward and you have just enough room to get in there with a razor blade and soldering iron.
 

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Discussion Starter #18
I'm hoping I've figured out the wire colors correctly. Read several posts with different information.

I will remove the seat entirely, makes it easier to get to everything and run my custom made harness.

Thanks for the info :)
 

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Discussion Starter #19
Well, everything went great! I tested the amp without mounting it and the driver side sounded a bit muffled/static at higher volumes. So I played around and ended up simply switching the RCAs around and everything seemeed great. Kinda odd, bt whatever works, lol.

I'll put the seat back in and finsih running my wires and hope it sounds as good as it did when testing.

So many wires to tap and splice and cut, you must be careful, or one wire can easily slip out of place or become disconnected.

I wanted to post pics, but my dig cam battery died :( Overall very clean, simple install, wihtout having to remove the dash and run more, longer wires.
 

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Well, everything went great! I tested the amp without mounting it and the driver side sounded a bit muffled/static at higher volumes. So I played around and ended up simply switching the RCAs around and everything seemeed great. Kinda odd, bt whatever works, lol.

I'll put the seat back in and finsih running my wires and hope it sounds as good as it did when testing.

So many wires to tap and splice and cut, you must be careful, or one wire can easily slip out of place or become disconnected.

I wanted to post pics, but my dig cam battery died :( Overall very clean, simple install, wihtout having to remove the dash and run more, longer wires.
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I'm glad it worked out for you. I found the bose wiring diagram pinned in this section was perfect. Did you have any issues with alternator hum when your car was running? I was pissed, when hooking everything up, I tested the connections individually with the car in aux and not running. When I got everything hooked up and went for a drive I had a wicked hum from the alternator. I ended up having to put in a couple ground loop isolators at the rca connections under the seat. Not a big issue, just annoying.
 
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