Modding stock HU for RCA outs

[garboui]

I found this on another board but its for the stock stereo in the proteges. Does anyone know if the internals in our M3 HU's is the same? or does anyone know if this has been done at all on the M3 HU's?

http://www.msprotege.com/forum/showthread.php?t=123620193

When i get my car back i might pop the HU open and do some probing. Or just do some looking through the datasheets for the IC's used in ours to see if there is an easy way to do similar in ours.


edit: reading further on in the thread. our HU's have a built in loudness feature thats active up to about 3/4 volume. This thread also goes into detail to oh how to disable this function.

[TheProfessor]

Why go through the hassle when you can just buy a LOC for a few bucks? -RJ3- is giving his away for free, just cover his gas money! For those who still have warranty, keep in mind that cracking the head unit open and messing with it will void the stereo's warranty, so if anything should go wrong you're SOL.

[garboui]

the whole reason for doing this would be 1. cleaner sound and 2. cleaner install.

alot of distortion is avoided by skipping the amplification stage of the HU as well as the distortation incurred form the loc's components. whats the point of taking a perfectly good signal, amplifying it then atennuationg it again to have a line source.

it will be a cleaner install because all wiring will be done inside the hu and not a huge mess of wires behind the HU or by the amps.

also doing this gives you a better freq response. if you look at the comparison charts on the linked page the roll off happens alot lower with the line out mod. this is most likley due to the fact that there is a high pass filter in the amp stage of te head unit to help make the stock speakers survive. this lower bass extention is also important for those wanting to run a sub because having that extra 10-20Hz of low end makes a huge diference to how a sub sounds.

[TheProfessor]

Have you heard a MZ3 with a LOC and good quality components? If so, I'm not so sure you'd think it was worth the trouble. Add to that the fact that aftermarket companies make items like the JL Audio Clean Sweep and the case gets even stronger. Now, if you intend to run a serious SQ set-up then I could see it possibly being worthwhile, but if that were the case you'd likely be going for an aftermarket deck anyways.

[Gizzmo_jr]

I've only heard praises from people who use the David Navone NE-774 in their Mazda 3's.

[garboui]

i do have a sub running with line levels and coaxials running off the stock hu. i will admit is sounds decent. my view on this is so such a cheap mod to get better sq, why not?

sure you can gain back some of that low bass thats rolled off with bass boost but its still a compramise.

[TheProfessor]

Well if you do give it a shot definately post up the results.

[garboui]

i have access to equiptment to do some probing but by the looks of the way things are going with my car im not going to have access to it to do some tinkering for at least another month. allthough is someone has a deck that has a broken cdplayer or something like that that still outputs to all channels i am open to donations for a deck to experiment with.

if i am successful with figuring out some outputs i will be posting full step by step instructions with pics.