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Isolated interface cable


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I have asked the question on another thread. The thread has since scrolled down the page.


I have a battery powered Zumo on my 12RT. I have the installed the radio auxillary outlet. I have purchase (will arrive in few days) an AmpliRider amplifier to boost the Zumo's audio signal.


The BMW factory radio is obviously bike battery powered.

The AmpliRider will be bike battery powered.

The Zumo is bike battery powered.


Do I need isolated interface audio cables between any/all of these devices? I have shielded 1/8" stereo (mini) cables currently. They are about 6bux. The isolated cables from Autocom are about 50bux.


I'm trying to eliminate any ground loop noise from the installation and protect the devices, in particular, my warranty of the bike.


Any help is appreciated.

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Warrantee should not be an issue at all with what you are doing.


To avoid having to buiy a ground isolation loop (GIL), attempt to have a common ground for all your powered sources.


I ended up having to get a GIL for my set-up since I was powering my XM off a separate power supply without a common ground.


There are cheaper GIL's avaialable, you can even make when with component parts from Radio Shack, however; I got the Autocomm and am extremely happy with it on my bike.


Hope this helps! thumbsup.gif

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Thanks for the reply

The Zumo and the AmpliRider will both go back to a Centech fuse panel. They will have a common ground at the panel. How's that sound?

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  • 3 weeks later...

Well the AmpliRider is installed. I removed the volume control and installed the resistors specified by Gary of AmpliRider. The volume is still too low. I'll probably end up going with the Canakit next.


There are some others problems. The radio, amp and Zumo don't start up very fast. In fact the original MP3 sound out of the radio is very garbled. It finally clears up a bit but is very erratic. The XM and the MP3 from the Zumo will sound OK and then they fall off in clarity. This only happens when going through the factory radio. It actually sounds better with the engine going than not.


The Zumo and the AmpliRider are grounded at the Centech fuse box. The factory radio obviously has a different ground. I was thinking that the problem is between the amp and the radio auxiliary mini cable.


Autocom sells the isolating mini cables for $49. I would hate to buy 2 of them if I didn't need to.


Has anybody completely fixed the problem yet? I understand the Canakit will bring the volume up with the stock radio/cd. Has the static issue been definitively solved?

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Thanks for the link. I've seen that thread. It seems like a well thought out option. My only concern is the clipping above 6v. Have you remedied that problem yet?

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The reason for choosing a kit like the Velleman, was that my buddy salivates the thought of an open PCB - and he seems to have every resistor known to man on his shelves.

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It is not a problem given the volume levels that I listen at - i.e it only clips at max volume.


That might be a problem for me. I typically have the radio cranked up in order to hear it a highway speeds. I've since installed a Vstream windscreen which quiets the environment considerably. I might not be at max volume but it's probably 95% anyway. I'm assuming this is in clipping range.


Thanks for the info.

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Harrington, if you're listening through the bike radio speakers it's highly unlikely that you'll notice the drop-off in quality amongst what's left of the wind noise - seriously!

You should consider that whatever you get is a bonus.


Good luck in your choice.



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