Had some time to tinker.
I took the ATX power supply out to the car and powered it up.
I connected the ground to the radio harness ground pin which is grounded to the chassis.
I then touched the 5v output to each of the speaker negative pins in the connecter that leads to the monsoon amp.
When I applied 5v to the left front negative speaker line feed to the monsoon amp the amp came on and the speakers were alive. No music yet just a pop like I expected.
So, that confirms everything I have read thus far. I plan on applying power to the left front negative speaker terminal and ensure the ground is to the chassis.
Now I need to pull the monsoon amp and replace the input feed with my replacement cable.
I connected the mac mini via 3.5 to L/R "Y" cord and ground loop isolator (GLI) to my experimental box.
The box splits the 2 outputs to 4.
5v was input to the LF negative line only.
I had music but I also had a buzz. Since the Monsoon amp is looking for a balanced signal I decided to connect all the negative leads and apply 5v across the board. This eliminated the buzz.
The only thing that remains is a faint buzz or hum when there is no sound output from the mac mini.
It doesnt happen when I mute the source only when I turn off all sound sources, iTunes, internet radio, sirius, etc.
This may be related to the fact that there isnt 5v on the positive inputs.
However, when the stock head unit is installed the 5/6v is only applied when the radio is turned on. So when there is no source there is no current to the amp.
I think the safest and easiest solution is to install a switch on or near the center console that lets me apply the 5v and turn on and off the amp.
I would like some help figuring out the buzz with no sound signal.
One other issue, when the key is turned off there is no head unit to turn off the amp. It just keeps playing. This will be handled by the P2140 PSU.
At least I can have sound for now and the quality is much better than the stock tuner.
Once the system is installed I will readdress the audio to include a miniDSP that allows me to control the output signals via software. I can the control the speakers independantly and create a sub out.
This will likely coincide with a new amp and speakers.
I can move past the audio and start modifying the mini. This is where it gets tricky.
I am putting the finishing touches on integrating my Mac Mini to my VW Monsoon Amp.
I have the amp working thanks to the FAQ posts.
I would like to install a relay that uses the presence of audio current to switch on the 5v needed to turn on the Monsoon Amp. If you are unfamiliar the 5v is injected into the negative leads going to the amp.
The purpose of this circuit is to turn the amp on/off based on the presence of an audio current. When the current is present the audio sounds great. If I close the MAC applications or browser providing audio output then I get a buzz from the 5v being applied. So, the relay circuit would ensure that the amp is only powered when there is current on the audio output.
Mac Mini --------Analog out 3.5mm to L/R RCA------Ground Loop Isolator---------Circuit box (splits the RCA to 4 channels, adds 5v to the negative terminals)------Monsoon Amp
The relay would connect in the Circuit Box
RCA positive lead ------ Relay Magnet--------RCA positive lead out to amp
5v PSU ----------------Relay Switch-----------5V applied to negative leads
What relay should I purchase?
What is the current across the Analog audio signal which will be used to activate the relay?
This goes beyond the thump problem.So, If I follow - you don't want the amp on unless the mini is sending sound...
Looks like you are trying to solve the anti-thump problem (yes, your aim is slightly different - noted). I am using the Fusion Brain to prevent the amp from being on until my computer is ready for it..
I would search on solutions to the thump problem and see if they can meet what you need.
BTW: using the FB (or other similar solutions) would require a little programming...
With the MAc mini turned on and playing audio from iTunes everything is fine.
As soon as close iTunes I get a buzz in all the speakers.
The buzz is caused by the 5v ob the negative speaker terminals. With no audio signal the amp should be turned off.
The only way to effectively do this is to sense an audio signal and power the 5v lead accordingly.
Yes, this will also solve the thump, but that is not the primary goal.
The Pac-Audio TR-4 may be the solution but I am waiting to hear back from Pac-Audio to see if this is an on/off switch.
More stuff on order, Pac Audio TR-4 and LD-10, FME to SMA adapter to connect the GPS antenna to the GPS USB dongle, 100 amp fuse and fuse holder from west marine, and a few parts from Radio Shack.
The driver for the GPS are installed.
16GB RAM installed in the Mac Mini. Now I can configure Fusion 4 and run windows apps.
Car was in the shop because the electric radiator fan burned up. Anyway, that is fixed and I have the car back.
I will begin testing all electrical components this week.
Its been awhile but the project is alive and well.
I have been working on my cars interior. Trying to get some replacement parts that never materialized. So, they are being covered in suede as we speak.
On the computer front.
I tested several different audio configurations while I got up the courage to dissect my Mac Mini.
I purchased a 12v (13.8v) power supply from radio shack. The ATX power supply was too squirly.
I connected the P2140 and bench tested the unit checking all the possible configurations with PSUmoni. I was running PSUmoni on a winxp desktop as it will not run in windows 7 on the Mac Mini.
I subsequently installed Win XP pro on the Mac Mini.
I disassembled the Mac Mini and removed the internal power supply.
I replaced it with an internal cable and a Case mounted DC plug. I have successfully powered the Mac Mini with both the P2140 and the Mac Mini's original power supply using a patch cable.
I have two additional mods to make to the Mac Mini and I will be ready to install it in my GLI.
ACPI "Y" connection.
Patch cable for the external wifi antenna.
Progress has been slow but deliberate.
Mac Mini is ready to install in the car.
3 mods complete.
Removed the internal power supply and replaced it with a new cable with a DC power plug.
Added a Splitter to the on/off switch to allow the DC power supply or a dash mounted switch.
Installed a WiFi antenna cable for an external WiFi antenna.
Here are some pics after assembly.
Everything works and the WiFi reception has improved.
Finally got the "B" and "C" pillars covered in black suede.
I can get the interior back together now.
I still need to cover the door inserts.
I started spewing foam foam the A/C vents. So, I will explore pulling the dash to replace the air mixing box. Not looking forward to this at all. The dealer wants $1600. Anybody pull your dash lately?
My MAC mini is installed and working.
Have to cleanup some wiring, install the USB hub in the glove box, and install the Xenarc 8" monitor in the dash.
Integrated the MAC mini sound output into the stock Monsoon Amp and they are getting along just fine.
Taking my time with this project paid off. I did a lot of bench testing and planning.
Here is where I am at:
The next step is to mount the USB hub into the glove box and install the Xenarc 8" LCD into the dash.
But I have a problem that plagues all IV owners, the dreaded foam in the A/C vents.
I have ordered a new airbox and all associated hardware.
I am going to create a DIY thread for removing the dash and fixing this problem the right way. I plan on replacing all under dash items including the heater core, blower fan, airbox, and A/C evaporator.
I should have that new car smell and no more foam.
I will post a link to that thread when I get it started.
Here is my new thread, DIY: Foam from the A/C vents.
I will continue to add to this thread the applicable tasks of mounting the video monitor in the dash and the USB hub in the glovebox.
Last edited by cazzz; 01-19-2013 at 04:00 PM.
I am back from replacing the airbox, evaporator, fan, and heater core.
Quite an under taking but the used car smell is gone!!!!!!! And no foam blowing through the vents.
I still have the radio cage and glovebox out so I can install my 8" LCD in the radio cage and the USB hub in the glovebox.
Here are some pics of my radio cage and disassembly of my Xenarc 8" LCD.
Monitor came apart easily by removing the four corner screws and prying the back off.
Disconnect the speaker wires from the motherboard and move the back out of the way.
Disconnect the button board, I left it mounted in the case for now. I will attempt to remount in the car. According to Xenarc the LCD panel will work without the board attached.
Remove the six screws holding the LCD to the front of the case and it is now apart.
I need to modify my radio cage by removing a portion of the top shelf.
I still think I am on the right track using the 8" LCD panel. Looks like it will fit perfectly.
this is amazing. i want to add sound deadening material throughout the entire car because i took my rear seats out and they did block some of the sound.
you're like mad mike from pimp my ride with all of that electronic stuff in the trunk
His prices are not the cheapest but the information is great. You will understand soundproofing after reading.
Most think dynamat is soundproofing and it is not. It is sound deadening, just stops the vibrations of the metal. It does not absorb sound.
That is why I used Mass Loaded Vinyl (MLV) throughout the car. In fact, I used dynamat then MLV. On the floor I used MLV with a foam backing.
After reinstalling the dash there is a significant reduction in noise from the front of the car.
When I open the sunroof with the cover still closed I cannot even hear the sunroof raise.
It is very nice to have a quite clean '04.
I still have to do the door panels. They will be next right after I install the 8" LCD monitor in the dash.
I bought the MLV from TM sound proofing, they had the best price.
Holy this is intnse
No turning back now. Just modified my GLI radio cage and modified the backside of the motherboard mount on the Xenarc LCD.
Now I modified the back plate so I can reinstall the motherboard securely.
Take deep breath and relax........
I actually created a channel the the LCD panel slides into.
The only problem is the the LCD panel will be recessed into the dash and not mount flush. I need some room for a bezel.
I am attempting to use the radio cage for support.
If this does not work or look right then I will trim the side tabs off of the radio cage which will allow me to mount the LCD panel flush to the dash.
This requires fabricating some type of mount. I am not sure how I would make the mount or what materials I would use. More than likely some type of sheet metal or bracket.
Might be making a trip to Lowe's and Ace Hardware for some ideas.
The bezel will be made out of fiberglass or carbon fiber and will not provide and structural support. So, I can do that last.