pop when connecting ipod

Hi, I have a very simple setup: factory Head Unit, CD changer used as aux interface, and my iPod connected to that.

I turn the ignition on, then connect my iPod and pop go my speakers... (It's more of a 'bang!' actually.) And nothing else comes out of them again until I turn the ignition of.

I'd like to understand what is happening, and fix it.

Additional details:

• The aux interface I have (bought from bortesi.it, I have a Citroen Xsara Picasso) has a wire that I needed to connect to a metal part of the car or head unit, which I have done.
  
• I have found a 'workaround': if I touch the cars metal and the iPod at the same time, for a short while, no pop when connecting the iPod. (If I recall correctly, touching the car's body directly with the iPod, it does pop again.)

Clarification: CD changer *port* used as aux interface, not a real cd changer.

Plug the iPod in BEFORE you turn the system on. That's the only thing that will "cure" this situation.

What is happening, is the amplifier or HU is interpreting a transient overload condition, and the protection circuitry is doing it's job. Just make sure your iPod is plugged in, and turned ON before you power the system up.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Thanks, I'll try that in the morning. But are you saying that there is no way to work around this? No way to make this transient overload go away, or avoid it?

I was thinking along the lines of installing something (large resistor?) to 'ground' the outside of the iPod to the car before it goes into the dock connector, or putting something between that wire from the aux interface and the car body?

It's not a static issue. It is all of the analog devices in the iPod turning on. NOTHING can be done about it.

:::EDIT::::
ALL active devices should ALWAYS be turned on furthest from the speakers first, with the amplifier beingt he last items powered up. This is why amplifiers have a "turn on delay".

Your hint should have been that "when I turn the ignition off, then back on, everything is OK." This scenario should tell you that everything works fine if the iPod is on and then you turn everything else on. All you have to do is turn it on, on the way to the car, plug it in BEFORE you turn the key, and everything will be just fine!

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Well that's the problem, it's not: I still get a loud pop this way, before I turn the ignition on.

So, wait... you're telling me that if you turn the iPod on, AFTER the ignition is turned on, you get a pop, and everything shuts down, right? Once everything is shut down due to this pop, if you turn the ignition off, and then back there is no pop? Am I understanding this correctly?

And if I am understanding that right, now you are telling me that even if the iPod is turned on, BEFORE the ignition, you still get the pop? Is this also correct?

If all of the above scenarios are correct, one possible solution might be this: Take a DPST switch, and wire the center (the "pole") to the chassis, and the input (the "throw") to the signal carrying conductor of the input. While waiting for everything to "warm up", have the switch on, which will short the signal to the ground, preventing the pop. After a few seconds, and everything has stabilized, then turn the switch off, allowing the signal into the HU. Try that, and let me know what happens.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Hi,

for the scenario's, it's not so much turning the iPod on, but simply connecting it that causes the pop. Normally, the iPod is still off at that time, and the ignition can be on or off.

When this has happened, the speakers are 'stuck' in this popping-mode where they pop whenever the radio is turned on or off, until the I turn the ignition off and back on. It sounds like some circuit is overloaded and not 'cleared' until the ignition is turned off.
After turning the ignition off, I can do what I want, including disconnecting the iPod, turning the ignition on and off, ... without popping again, until some time later (say the ride home when the first pop is when driving to work).
This also makes it hard to test things, as I can do just one test per evening.

And thanks for that suggestion (and for trying to help in general). It may take me some time to see how to put that together, I'll need to find out what you mean by DPST switch first ;-)

Oh and I've described my situation with even more detail here:
https://www.citroenpicasso.org.uk/picasso/index.php?showtopic=12524&st=0&gopid=123900&#entry123900
perhaps that is clearer than my description here.

legolas_a20 wrote:

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And thanks for that suggestion (and for trying to help in general). It may take me some time to see how to put that together, I'll need to find out what you mean by DPST switch first ;-)

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Double Pole, Single Throw. It is two independent switches, activated simultaneously with one action of the toggle or rocker. This switch will have 4 terminals on it.

You can use a DPDT, (Double Pole, Double Throw) also; this switch would have 6 terminals on it, you would just not be using two of them.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."