amp - here are the descriptions:

1. The amp is grounded to the grounding point on the passenger side of the front trunk side wall.

2. The ground wire is pretty thick as it was part of the monster cables purchased with the amp.

3. The grounding point is the one Porsche uses for another wire. It also has the passenger side HID ground wire. The popping was happening even when the HID was grounded somewhere else.

4. The amp is mounted using screws to a wood board behind the trunk carpet. See the picture below - I have lowered the amp since putting in the strut brace - the amp does not touch the strut bar.
<img src="http://boards.rennlist.com/upload/StrutBar4.jpg" alt=" - " />

5. The amp wires run down and around the front of the trunk before entering the passenger cabin through the hole near the pedals. The power wire runs from the battery to amp around the front of the trunk. (The popping also occurred when the entire HID unit and all wiring was in the light well.)

6. I unhooked the line out to the amp from the head unit and ran a wire from the speaker out connection directly to one of the speakers. With this setup, there was NO POPPING.

7. I just tried to unplug the CD changer and it still did the pop when turning on the HIDs.

8. The pop is the same if the engine is running or not.

** Could this be something that is typical with Alpine because Renato is having a similar issue.
** If I was to mount the amp under the passenger seat (like you have it) do you think that would solve the problem? I don't want to go through the effort if it has no hope of resolving the problem, but will if it is recommended.

Thanks so much for your interest and help.

-Skip

 

There's no obvious problem that I see from your descriptions. If I were to troubleshoot this problem, the very first thing that I would invest my time in, is to locate and resolve any ground loop points between the amp, the head unit and possibly the HID ballasts in your setup. The number one cause of noise in audio systems is directly attributed to ground loops.

<a href="http://www.audiocontrol.com/techpapers/tech1002.pdf" target="_blank">Tracking Down Ground Loops</a>

Second area of 'attack' would be to shield any signal wires to/from the amp and your head unit. Especially the point where the signal wires run parallel with power wires or pass through the firewall. Try wrapping these signal wires in alum foil as quick test . . .

I would not attempt to relocate the amp at this point. Installing the amp under the passenger seat is not a trivial exercise (don't ask me how I know <img border="0" title="" alt="[Wink]" src="wink.gif" /> ).

Good luck and keep us abreast of your progress.

 

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">** Could this be something that is typical with Alpine because Renato is having a similar issue.
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Could you go to a stereo installer and borrow and temporarily install another type of amp to see if that changes anything?

 

Amp - THANKS

I have checked the grounds for the head unit, amp and HIDs and they are all using factor grounding points.

When you say the signal wires, your talking about the speaker wires that carry the music signal? Right...

The amp power wire from the battery runs around the front of the trunk along with the speaker wires (both sets - inputs and outputs). Sounds like I should run the power and speaker wires so they are not together - is this correct?

I can work on this tonight...

 

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by swftiii:
<strong>
When you say the signal wires, your talking about the speaker wires that carry the music signal? Right...</strong>

The signal wires are the ones that carry audio signals from your head unit to the amp. These are the wires that are most succiptible to noise.

<strong>The amp power wire from the battery runs around the front of the trunk along with the speaker wires (both sets - inputs and outputs). Sounds like I should run the power and speaker wires so they are not together - is this correct?
</strong>

If you can, separate the amp power and ground wires from the amp audio input lines by at least a few inches. That may help as well . . .
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">

 

Amp or others - I have separated the amp input signal wires from the amp power and ground wires. I still get the popping.

What now? I'm at the end of my rope and think I'm going to just live with it until I replace the head unit. Do you think moving the amp inside the passenger cabin solve the problem?

A question for you as you seem to really know your stuff. How would a head unit putting out 4x60W without the amp do compared to the stock head unit with the 4x75W amp. I have MBQuart (approx 8" round) front speakers and Boston Acustic (approx 6"x9" square) rears. Without the amp the sound is terrible, but with the amp it is great (good base and crisp as loud as I would ever need it).

Thanks again for all your help!!!

-Skip

 

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by swftiii:

<strong>Amp or others - I have separated the amp input signal wires from the amp power and ground wires. I still get the popping.</strong>

Don't despair! You're chasing one of the most difficult to solve problems, audio noise. It took me over a month to resolve an issue with alternator noise after I installed CDR-220 and an ADS amp. It turned out to be grounding of my hands free Nokia kit that produced the noise. Believe me, I was climbing up the walls!

<strong>
What now? I'm at the end of my rope and think I'm going to just live with it until I replace the head unit. Do you think moving the amp inside the passenger cabin solve the problem?
</strong>

Don't give up, at least not yet <img border="0" title="" alt="[Wink]" src="wink.gif" /> Let it go for a few days, let it sit and jell in your head a bit and you may see another path or discover something that you've missed. Moving the amp under the passenger seat might help the situation but most likely just be virtue of picking up another ground location and getting shorter head unit to amp signal wire runs. Before moving the amp, I would try a few more things.

Disconnect the plugs from one of the Catz ballasts and see if it makes any difference. Reconnect, and try the other side. Any change?

Head out to Circuit City and look at their amps. 30-day, no-question-asked return policy is a wonderful thing . . .now come down boys, I’m not really suggesting anything here <img border="0" title="" alt="[Wink]" src="wink.gif" /> . They carry Sony, Alpine, Kenwood and others, I believe. Pick one up that closely matches your power/ground and signal/speaker connections. Connect it up to your harness and do a quick test and see if that makes any difference . . .
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">

 

I think your problem is related to the high voltage ignition used to start the lamps. These arc lamps need around 15-20KV to strike an arc between the electrodes. The ignition pulse to the lamps is coupling to the wires of the amplifier. To fix the problem, you need to shield the wires coming out of the lamp ballast. I think that is easier than shielding the amplifier and its wires. Also, moving the amp to inside the car will most likely solve the problem.

To determine if wire shielding will work, get some aluminum foil from the kitchen and wrap it around the wires to the lamp. If the foil works, you can buy some metal braided wire jackets from an electronics supply store that will give you a professional installed look.

I work for a company that makes HID lamps and power supplies. The EMI emissions with an arc lamp/ballast can sometimes give neighboring electronics a fit.

Good luck and keep us informed

 

You 993 guys have it rough, huh?

They make the real deal litronics so expensive, everyone runs out and buys aftermarket and then has problems, well what do you know?

Wow, my litronics have never caused any problems and they are NOT grounded to the same place as my amp.

You shelled out the $$ for the P-car, c'mon, do it right!

Yea, I know the 993 lits will set you back over 2 g's but I'll bet you won't have these problems.

 

Chris,

Thanks for the ideas...

I tried covering all the HID wires w/ aluminum foil and the pop is still there.

All of the hid components and wires are in the light wells and the amp is in the front trunk. These are separated by a metal body panel. Do you really think moving the amp under the passenger seat will resolve this problem?

DCFLAT6 - I'm not going to spend 2,500 for the Porsche litronics and there is someone who posted within this thread that the same problem is occuring with his Porsche OEM litronics.

-Skip

 

I spoke with one of the guys at work about your problem. His thought was ignition pulse from the ballast was being conducted onto the ground wire at the ballast. There is being very limited filtering on the power and return lines.

Have you tried disconnecting one or both lamps and letting the ballast try to start the lamps. Does it go pop..pop..pop? If it does, it would confirm the ignitor is the cause.

 

Eurocarguy,

Thanks for the help.

I unhooked the wire to the igniter, which left the power to the ballast, but wouldn't light the bulb. The pop was not there, so I think it is isolated to the ignition/igniter.

Now the question - how do I isolate it so it doesn't affect the amp?

-Skip

 

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by swftiii:
<strong>Now the question - how do I isolate it so it doesn't affect the amp?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Have you tried wrapping the wires and/or the ballasts in alum foil yet?

 

The aluminum foil itself must be grounded somehow too, otherwise it will not shield.

Chip