Audio interference with car charger
 

I bought an n810 about a week ago and think it's awesome. I've been buying a bunch of accessories, and just have one problem so far:

When I'm using my car charger and audio out (to my car stereo), I get a lot of interference. I've tried quite a few different setups and this is the only one that has problems.

Using the audio out to my home stereo with the wall charger works fine, car audio while not charging is fine, etc (I can list a few others if it will help).

My car charger is generic, so I tried a Nokia charger today but still got feedback, along with a variety of audio cables.

Has anyone else had this problem or have any suggestions?

I noticed that using the car charger with the Nokia-provided head phones also works, so I was thinking of trying to find an audio cable with an L-shaped plug.

Side note: I plan on using this primarily in my car. The GPS seems decent enough, I'll be getting an 8gb card pretty soon for mp3s, and Bluetooth PAN works for Internet (Did I mention this device is awesome?). The charger issue makes it a little less convenient, so I'm really hoping I can get it fixed.

Thanks for any advice!

- Andrew

Re: Audio interference with car charger
 

I also get annoying interference when I use the car charger with my N800.

What kind of cable do you use to connect your tablet to the radio? Do you get any kind of hiss when the charger is disconnected? Have a look at this post: http://www.internettablettalk.com/fo...d.php?p=197599

Re: Audio interference with car charger
 

I also get pulsing interference when charging my N800 in the car. Keeping the applications volume and the N800's master volume at max minimizes it's effect.

Re: Audio interference with car charger
 

@johnnybravo: I saw that thread yesterday and it inspired me to post my n810 question, but it's not the same :) This only affects audio when charging, and only with the car charger (as far as I can tell). It sounds like a pulsing and a low buzz. I use a standard 3.5mm audio cable. This doesn't affect the speakers either.

@gowen: Thanks for confirming. That's exactly it. A pulsing sound that is easy to ignore with music playing close to max. My guess is that it's because the power and audio jacks are right next to each other.

In fact, they're so close together that the first audio cable I had was too big to even plug the power in at the same time.

Anyway, I'm glad that it's not a problem specifically with my n810 (or car outlet). I'm far from an audiophile, but I guess I might try to find a more expensive audio cable that claims "low interference" soon.

Re: Audio interference with car charger
 

Interesting - I have the same problem, but assumed it was due to the rubbish usb charging lead I have plugged into the usb port on my griffin Itrip, or due to the charging current being a bit on the low side for the N800.

What are others charging with? via usb like me, or a seperate car charger?

Re: Audio interference with car charger
 

Someone told me car power is notoriously "dirty" and that I'll probably need to get some kind of filter for it. They also said getting a higher end audio cable probably won't help.

I'm charging with a regular car charger, not USB. I've tried with both a Nokia charger and a generic brand.

Re: Audio interference with car charger
 

It sounds like a ground loop is causing the buzz. As someone mentioned before, car power is very "dirty", and unless you use very expensive shielded cables it will cause interference with the audio cable. You could try using a ground loop isolator like this one between the tablet and your stereo. It's big, bulky, and ugly, but it should fix the problem.

Re: Audio interference with car charger
 

@jellotherat:
Thanks for the info. I've done a bit of searching and found one at crutchfield that I might end up buying. I'm going to do a bit of research since, from what I've seen at least, it sounds like the ground loop isolator will get rid of the slight buzz, but might not get rid of the thumping/pulsing sound.

I'll be trying a ferrite "choke" tomorrow, but it will probably be quite a while before I try something more expensive. I'll update the thread with any new info.

Thanks for the help.

Re: Audio interference with car charger
 

In addition to my comment above, I have found the same problem when charging my N95 whilst playing audiobooks from it through the car stereo.

Re: Audio interference with car charger
 

Oops, I meant to update this thread earlier, but I guess waiting was better so I can give the good news :)

First of all, just using ferrites didn't solve the noise when plugged in to my car charger.

But, as jellotherat suggested, a ground loop isolator worked perfectly! Crutchfield has one that's inexpensive and has 3.5mm m/f so it works with regular audio cable:
http://www.crutchfield.com/App/Produ...=noise&tp=2653

I had both a low buzz and a rhythmic thumping and assumed the ground loop would only get rid of the buzz, but I'm glad to report that it got rid of both. Now I can charge my n810 in my car. Of course, I don't think it will come in very handy for a while since I can't leave it alone so it ends up charging at night when I'm at home :)

Hope this helps anyone with a similar problem!

- Andrew