Making your own Active Mount...?

Daaave · Posted: Sun Aug 05, 2007 11:32 am Post subject: Making your own Active Mount...?

Hi everyone,

I have a cubby hole in my car dashboard that the TT 720 fits nicely into. I would like to be able to have all the cables (power and line out) wired into the cubby hole so I can easily mount the TT and remove it when I want to for swapping to another car or whatever.

As there aren't any active mounts out there yet, I wondered how easy it would be to make my own... I don't use the USB PC docking unit (I have enough cables and proprietary 'mounts' for other gadgets crowding my desk) as I just use any mini-USB lead that's free.

So I wondered if I could take the docking unit apart and make my own active mount? I need to get a 90 degree 3.5mm jack for the line out, drill a hole and glue it in position, and I'm hoping that I'll be able to re-wire the cable for a 12 volt power supply rather than USB.

Has anyone ever tried this before?

999tommo

Daaave

mikealder · Posted: Tue Aug 07, 2007 9:34 pm Post subject:

What you need is a "Ground Loop Issolator" there is a problem with the ground (earth connection) between the supply feeding your 720 and stereo - the easy option is to fit one of These between the two devices or use the FM transmitter built in to the device and do away with both the cable and the problem - Mike

Daaave · Posted: Tue Aug 07, 2007 10:04 pm Post subject:

mikealder · Posted: Tue Aug 07, 2007 11:20 pm Post subject:

If you use a ground loop issolator it will get rid of the type of noise you describe, the device is only required if you use the direct wired connection between the stereo and TomTom device.

I would try using the FM transmitter built in to the 720 and tune the cars radio in to the same frequency, you can have the sound through the car system without the problems of a direct wired connection, thus negating the need for the ground loop isolator - Mike

Daaave · Posted: Tue Aug 07, 2007 11:48 pm Post subject:

Sorry I don't think I was clear enough, what I meant was as things currently are (i.e. without the isolator) shouldn't I get the same background hum on the stereo no matter what the output device was?

So no matter if I connected a TT, Ipod, PSP, walkman, etc, (and had the TT power plugged in) then I would have thought the noise should still be there, but it isn't. It's TT specific... Confused

mikealder · Posted: Wed Aug 08, 2007 7:41 am Post subject:

Some devices will generate this type of hum, others do not so the Ground loop issol is ideal for those cases where a wired connection is providing noise on the speakers.
It is the physical connection that is causing the loop and associated noise, try switching the audio output of the TomTom to the FM transmitter and tune in the radio to the same frequency, do you still get the noise using this method? - if you do then it sounds like the TT is faulty - Mike

markjohnson · Occasional Visitor Joined: Jan 20, 2006 Posts: 41

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