So, I go out to the car this morning and find a bubble in the sidewall of my left front tire.
Of course, I need to hit the road tomorrow and really don't want to blow a tire.
I was planning on refinishing the wheels at the same time I buy new tires and after I get the computer installed.
Can't wait now!
Made a deal for tires and $5 per incident to dismount / mount the tires. So, it looks like I will throw on a set of tires and refinish the wheels one at a time.
Probably won't do much today with the computer.
These tires were on the car when I bought it and they suck. Might be good tires but the alignment was out and they had never been rotated or balanced. I am really looking forward to a reduction in tire noise.
Ok tire problem dealt with. I went out on a limb and bought Cooper Zeon RS3-As.
They were available today and they ranked very high on Consumer Reports.
Only time will tell.
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 finished the temporary interface box.
Molex connector goes to the ATX power supply. The grey connector goes to the amp. The black wire goes to car ground.
Now I am ready to hook it up with the mac mini and see if I have sound.
Had to take my dog to the in-laws for the week. On the way he took a big steamer in the back seat.
Its always something.
Looks like the steam-cleaner is getting a workout tonight.
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?
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...
This goes beyond the thump problem.
Originally Posted by nasa
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.