MJHSC400

I was able to get this mod to work very easily by hacking into the signal lines of my non-working cd changer (slightly partially working rather).

I finally installed my MTX 1500dx (960w rms @ 2ohm -- Class D) -- 4200x (70x4 rms @ 4ohm) - And an infinity Kappa Perfect 12.1 -- Plus an audiocontrol 2xs (9v line driver, 2way crossover @ 18db per octave-- also isolates ground loops very well) --

The Signal voltage from the head unit to the factory amps is pretty low and it doesn't want to power two amp inputs very well or effectively-- not to mention it's a very noisy signal-- So I needed a Line Driver and a noise killer-- Audio Control is one of the best in the business- we all know that-- I have an eql to go in it's place once I have it repaired by Audio Control-- I think its 10 years old, and some of the faders are getting tired-- They'll fix it for $35 flat rate- goes for anything they build that's out of warranty-- minus replacing the whole board-- that's pricey I'm sure--
This was installed quickly and is definitely not for looks-- But it does sound very good !!


No more Factory Sub-- The sound carries very well thru this sub hole-- With ZERO trunk rattle!


I will still be putting my components in, I'm just impressed with the quality of the factory speakers-- The rears are great for fill, and will be fine if kept on the stock amp-- as they are on a band pass frequency only playing mids with no bass at all--

This factory system is sophisticated and I am truly impressed-- I just don't like the weak amps--

GROUND LOOP! -- Edit: Fixed with the AudioControl 2Xs crossover/line driver-- System is noise free!--

I've read that these are elusive in this stock system, and will be attempting to counter this problem by simply pulling everything to one ground, but I will see if the power wire I run fixes the problem too-- It's possible-- But I'll know for sure later today.

vstyle444

do you knwo have to hack the signal line on a 01 gs300 w/nav? do you have any diagram thankz

Jewcano

iTrader: (4)

This piece right here did me wonders

MJHSC400

The nav option should be irrelevant to the function of the cd changer, and it will have separate lines that connect audio signal into the head unit-- I don't know the GS, but i would be willing to bet the audio systems are nearly identical in terms of function, and it would only take a small bit of time to find which lines feed audio signal to the h/u...

Good luck with it too-- I found my car's diagram here-- if it helps any--

Ground Loop

The ground loop did not exist, it was just the old cheezy amp I was using to test this setup, actually it's not a cheezy amp, it's just old and I've had it apart a few times --- It still actually cranks out some solid sound, as they are very solid built amps even by todays standards..

I plugged in my mint Thunder 4200x 75x4 in it's place and VOILA!! Zero alternator noise--

Beautiful--

The mod works perfectly--

vstyle444

which wire did you use on the plug and how did you connect to make it come to a rca/ipod plug? thankz in adance

MJHSC400

So if you are looking at the "output" plug from the changer, you'll see R+ and R-, and L+ and L- , these are low level signal lines around 2v +/- a little..

All you do is get some female RCA plugs from radio shack and solder them in-- I actually disconnected them completely from the changer, but they can be left connected if you wish using the relay method-- but that takes a bit more work to make it happen, and I am moving as far away from hundreds of cd's as possible-- as I just plain hate them-- too much mess--

It's funny-- My cd changer decides to start working again today, -- hasn't since I bought the car months ago-- until today when I finally get the system working like I want it -- Coincedence??

vstyle444

so its the plug from the socket 'C" right? so you use C1= CD R+ n C6= CD R- for one side n C2 n C7 for the other...also how can i wire it up to a relay to get the changer to work too...thankz alot

MJHSC400

There is a writeup just a few days old if you search this forum--

MJHSC400

Ahhhh - I installed the freakin PIE line driver to discover a new source for alt. whine and ignition noise (a LOT of noise for that matter) --

I pulled that crapper out and installed my old and trusty EQL, and voila, ZERO alt whine, no ignition noise, no turn on thump--

Also, the signal to the amps is much stronger, making the system loud enough to leave alone for a while-- plus the eql has a serious range of adjustment to tailor the frequency levels to your liking--

So far I've just boosted the high frequencies a bit to compensate for the weak factory tweets and I must say I'm impressed with the stockers --

I am also crossing the front mids (factory too) at about 70hz @ 18db/oct...

The sound is now in the "Excellent" range for stock speakers -- very very good...

I'll post up a pic of my install -- It's just a quickie, but it works well....

MJHSC400

Also-- I'm presently working on a design that will have the same basic functionality of puredrifter's source switching aux input--

I want to build an auto-sensing circuit using a darlington pair (transistors) sensitive enough to trigger a single 4pdt relay to switch from the cd changer source to the mp3 player/ aux input source.

The theory here is that a darlington pair will be sensitive enough to sense the mp3 player's tiny voltage even when it's at rest between songs--

This came about as an idea when I looked down and my cd changer no longer said ERR -- instead it was playing the #1 cd-- I was amazed-- It has worked since -- Though up until now it hadn't worked since the day I bought the car a few months ago..

Several companies use auto-on technology in amplifiers for 12v audio as well as for home powered subwoofers and other home audio amplifiers. The amp just basically senses an input signal and turns on by itself--

It's very probable even though I haven't seen a schematic that they're using a transistor and solid state relay to possibly trigger a larger solid state relay or something along those lines--

Any input from someone with electronics background will be welcome.

MJHSC400

updated-- pics of install

PHLSingle

AWESOME! Just did this mod over the weekend...I love it, thanks for the info !!!

Now...If I could only figure out why the audio from the right side has only a fraction of the volume as my left side!! (no the balance isn't set all to left!)

Jay

MJHSC400

That's funny-- I had the same problem-- but then installed an audiocontrol 2xs and the noise and imbalance were both fixed-- And it's a 9v line driver, so I was able to feed my amps what they need to come to life since I'm using the factory head unit ---

PHLSingle

Hmmm...interesting - so just adding a xover did it huh?

MJHSC400

Adding an AudioControl xover/line driver/ plus triple isolated ground did it--

All audiocontrol's units are triple ground isolated-- but digitally -- so you don't get that crappy attenuation and varying signal of a wal-mart ground loop isolator--

You can find the older audiocontrol units on ebay or *.craigslist.org pretty cheap-- A 2xs is all you need-- but an EQL would be awesome, so you can have 1/3 and 1/2 octave equalization and maintain the stock head unit--