Thread: vw mk4 monson amp and another amp

what i did was this. i stole the 5v from the computer (red wire) with 18 gauge wire then simply connected it to the left common. the audio is split this way, a 1/8 to rca cable from the computer...spliced and soldered into 4 lines of 18 gauge speaker wire for FR, FF, RR, and RF. anything connecting to the monsoon amp was connected at the grey harness on the amp with radioshack tap line connectors.

Just wanted to clue anyone in that theres a similar thread going now that R32 Juhl published his diagram:

http://www.mp3car.com/vbulletin/show...oon#post591924

whit the 5v regulaotr i used a heat sink so all the heat is being removed with the regulator as it is only rated at 1 amp so no worrys the output of the car puter could be up to 5 amps. i would use a regulator if i where you.

Originally Posted by vdoubleu

what i did was this. i stole the 5v from the computer (red wire) with 18 gauge wire then simply connected it to the left common. the audio is split this way, a 1/8 to rca cable from the computer...spliced and soldered into 4 lines of 18 gauge speaker wire for FR, FF, RR, and RF. anything connecting to the monsoon amp was connected at the grey harness on the amp with radioshack tap line connectors.

So are you feeding the 5V signal through the entire car harness... all the way back to the radio?

Originally Posted by alimh

I need some advice now...

This is my setup:
I have a 1/8'' connector (regular stereo) that has 3 pins (left, right, and common). The left wire connects to the LF+ and LR+ of the monsoon. The right signal from the 1/8'' connets to the RF+ and RR+ of the monsoon. The common from the 1/8'' connects to the LF-, LR-, RF-, and RR- of the monsoon as well as a 5v signal from the m1-atx power supply (red wire).

The amp turns on and I hear a little bit of static to confirm... The computer turns on fine... but when I plug the speaker 1/8'' plug into the computer, everything shuts off! This only happens when both the speaker 1/8'' plug AND the 5v turn on are on. Any ideas?

Also, I used the 5v from the m1-atx but plugged the 1/8'' connector to the output of my laptop sound card and it works perfect!

I think it might be a grounding issue... maybe the 5v is going back to the soundcard (which is grounded?) so there is a short. Also, somebody in the thread mentioned that their setup was getting really hot... maybe mine shuts off but theirs is still shorting but instead of turnng off just getting really hot. I guess I need to put a capacitor to block out the DC from coming back into the soundcard, but I don't understand exactly where to put it...

Any help would be much appreciated!

Test this: Install a 10k ohm resistor in series from the power supply to the amp.

+5v-----10kresistor-----amp left channel common

Let me know if that changes anything. I tried my work-around on two different sound cards and did not have any trouble. And I believe you're saying that you can hear your laptop perfectly through the audio system, but your carputer doesn't like the 5V coming in. Let's see what this does.

All right! Good news from the desert:

I was playing around and got my setup to work. I have a m1-atx power supply, and a on-board soundcard (on my mini-atx motherboard) hooked up directly to my Monsoon amp. It works and sounds awesome! There is some slight audible noise but nothing too bad (could just be the quality of the mp3...?). I am posting a picture of my wiring diagram. Hope this helps to all you dubber's trying to hook up directly to the Monsoon amp.

I would be great if this info could make it into the FAQ, there seems to be a lot of vw owners here.

I GOT MY PROBLEM FIXED!!!

in case anyone else runs into the same problem....my setup basically looks like alimh's diagram but i used a diode where he used a capacitor.

I still have a little noise when the computer is on.

But my biggest problem is that I have a LOT of noise when the computer is on, the amp is on, but the lilliput is unplugged. Anyone know what the problem might be?

try only putting the 5v to the left front speaker common.. alos make the cap bigger to 1000uf or more then place another cap inline so the negatives are tied together... when the caps are tied together like that it makes a dc filter and since you are entering dc into the speakers it is what you are hearing.. also when the caps are tied together like that is it like a 500uF cap so bigger is better but i found 1000uf to 2200uf works good.