BrianC

Some of you may recognize me from a few months ago, but I haven't posted in a while. Recently I got my act together and bought stuff.

OK here is a rundown of what's going on in my car:
It's a 99.5 A4QTMS, with stock Concert headunit (non-Bose), and the Panasonic DP610 changer in stock location, which has worked fine for a while.

When I decided to upgrade, after carefully considering my options, I decided to get the MB Quart 5.25 front adapters, the Blaupunkt pre-out adapters, DEI Studio 5.25 Components, PPI PC 4400.2 50Wx4 amp, and a JL Audio 10W3 woofer in the factory ProWedge sealed enclosure. I wanted to keep the rear speakers stock, running off the signal from the head unit (not the PPI amp)

The install: Getting the speakers to fit in the doors was the biggest chafe. One of the reasons I got the DEI's was their tiny neo-magnet woofers have very shallow depth. They fit in the Quart adapters, and the tweeters in the stock location, but I had to Dremel them a little bit to make it work. (NOTE: I did not cut any metal in the doors. This is unnecessary in a 99.5. Just shove it in.) Running new speaker wire into the doors was tricky. Use a coat hanger.

The back of my Concert had the one-piece harness, so using the Blaupunkt adapter was not exactly plug and play. (For info about this harness, check JohnP's archives. They were very helpful) Instead of cutting the Audi harness (risky), I cut the blau harness. I simply took a front left and front right RCA-out from the blau harness, and plugged them in the empty pin-slots. Bingo, $4 investment and I have front pre-outs. No modification to Audi. My amp has a "combine" switch, which doubles this front signal for front and rear output channels. Rear channel is bridged for the sub. Remote turn on lead is just plugged in with the pre-existing lead for the stock integrated rear amp.

I took the car in to have a pro (John at Stereo Types in Charlottesville, VA) do the power and ground wiring (both 4 ga.). He ran the power down the PASSENGER side, and the ground is attached under the back seat. The other wires, for now, just run through the passenger compartment, until I get this problem resolved.
After everything was hooked up, with the car off and the stereo on, everything sounded great. When the engine came on, I got this terrible whine. It fluctuates with RPM, but stays at a constant volume, regardless of the volume of my music. We tried different RCAs, and ran them outside of the car. That didn't change anything. I know that most people have run their power down the driver side, but at the time, I just let the installer do his thing.

>>Could this be the problem? Is there something in the passenger side of the engine compartment that is causing this interference? Could it be a bad ground? Again, there is NO NOISE WITH THE ENGINE OFF. What's going on? Any help is much appreciated.
Any new guys who have general questions are welcome as well. Thanks.

Andy H

I just finished my install (Diamond Hex's - had to cut metal on my door, PPI amp) earlier this week and I'm having the same problem with alternator whine.

I have my 4 gauge power down the left, monster cable 201xln's down the center, and speaker wires down the right.

I've been doing some reasearch and I've come to the conclusion that I have some ground loops. I guess these ground loops send current through your RCA's (not supposed to happen) giving us the variable pitch whine we are hearing.

You can buy a Ground loop isolator from Radio Shack for $ 15 which will significantly reduce the whine but it will not get rid of it completetly. Some believe that this diminishes sound qualtiy however some private testing using lab grade audio testing equitment revealed that the sound quality loss is negligble. This solution will not satisfy me, but it does make my system bearable until I can isolate the problem.

The best way to solve this problem is to eliminate the ground loops, however this seems very difficult.

I have been attempting to isolate my ground loops to no avail. I sanded the paint off at my ground and grounded my headunit and amplifier to the same ground in the trunk. I've tried both the bolt in the rear left of the trunk on the front left and neither remedied the problem. The resistance for each was less than 1 ohms, which would suggest that they are reasonable grounds.

I'm going to run a ground to my battery and ground my headunit, rcas, and amp all to my battery directly when I get some more powerline. Hopefully this will solve my problem.

D.Ross

Brian.. what side did you run your RCA's on? Also, one of them may have a shielding defect.

BrianC

DRoss:
RCAs are not permanently run yet. They were moved around, etc. in relation to the power wires, even routed outside the car, to see if that had any effect. It didn't. Double-Super-Duper Shielded Monster Cable RCAs were tried to see if that helped, and there was no improvement. I don't think the RCAs have anything to do with it.

BrianC

Anybody?
Andy, You sound very knowledgeable on the subject. I'm about to go off for a few days. Please let me know what you find out. Thanks

D.Ross

but one of them had a sheidling defect and after replacement all was fine. I'd say the problem most likely has to do with the blau convertor and stock headunit and such. It's so easy to put a single din deck in there, why not just drop that garbage and get an aftermarket unit? Kenwoods match the dash quite well. I just didn't wanna drop a whole bunch of cash on a system and then have problems with the crappy stock HU.

Mooney

I'm running the blau adapter to the amp off the stock symphony head unit.

I have the power and left front door speaker wire running down the left. Monster 2 pair XLN's down the center, and passenger door and remote down the right side. I'm grounded to the driver's rear passenger seat belt bolt. I'm getting the whine all through the rpm range. I'm going to try some different ground points tomorrow, but I'm not hopeful. I'm also going to try some different rca's not run down the middle (just out fromthe head to the amp to try and isolate the problem.

This whine is unbearable at low noise levels, you have to be cranked up to get around it. Details tomorrow on the further troubleshooting efforts...

siberian

I noticed the common denominator between all of your systems is that you are all using the stock head unit. I think your problem might be that the output voltage on the pre-out from the head unit is too low to reject noise. Take your ohmeter and check the voltage on the signal cable leading to your amp.

I did my own install and ran power down the driver side, RCA's down the center, and speaker down the passenger side. I have absolutely ZERO noise with the engine on. However... I used an aftermarket head unit that has a relatively high (4.5v) output on the pre-outs. The rule of thumb is that the higher the output voltage, the better chances of rejecting noise. That's why you see many cheaper aftermarket headunits have small voltage on the pre-outs.

Here's something else to consider... what kind of RCA's did you use? Are they shielded AND twisted pair? Shielding and Twisted Pair also help reject noise. I used Stinger Dream Series which utilizes the above mentioned construction.

Getting back to the voltage thing... if you indeed do have a low voltage.. I believe someone makes a line driver that steps up the voltage... but I don't know who off hand.

Hope this helps.

Mooney

Well Siberian hit it right on the nose. Apparently my 2000 Symphony's line outs are not powerful enough to supress the noise. I have a brand new Panasonic head unit that I was planning to install, so I took it out and hooked it up to test with.

The only alternator whine I could get was when I muted the radio and then it was barely perceptable. On the lowest volume setting, there was no whine at all. My new HU has 4.5v preouts like Siberian's.

Now I don't have a meter, but I'm going to bet the voltage on the stock preouts with the Blau adapter are very low.

So this is just accelerating my head unit install. Fun fun fun... Thanks Siberian!

-Alex

Mooney

Do you have any pics of your single din install?