Autocom Isolation Adapter

[BmKev]

Hello all

Autocom states that an isolation adapter must be used if both the Zumo GPS and the Autocom are bike powered.

Does anyone know if this is just advised, to avoid interference, or is it mandatory, to make a proper isolation between the two devices?

I intend to power the two from the same source (both +12v and ground) so there won't be any other loop in the wiring.

Thanks

Kev

[Ken H.]

I have mine both bike powered (Zumo 660) w/o the isolation adaptor - no issues.

[krussell]

I had noise with my 550 and SuperPro AVI that went away with an isolation adapter. I used both the Autocom 1314 as well as a radio shack part. Both worked fine, I ultimately went with the Autocom part because it was smaller.

 

I did struggle with the autocom part picking up noise. It was inline not to far in front of the seat along the frame and that didn't work well. Later I upgraded all of my wiring to well shielded stuff and moved the isolator to the tale of the bike where the autocom was. All was well.

 

The complete story at

 

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=311441

 

 

[BmKev]

Thanks for your replies so far. I forgot to mention that I have a 2009 Autocom model (L-1 Logic). Could this make a difference? Autocom seems to insist on "2009" in its isolation adaptor document. The Autocom and Zumo are placed close together and powered from the same source so interference shouldn't be a problem.

I wouldn't like to fry my new Zumo/Autocom due to a galvanic isolation issue.

Cheers

 

Kev

[FlyingFinn]

You are not going to fry anything from not using a ground loop isolator. Assuming all the wiring is still done correctly.

If anything you can get noise from the ground loop that's being created, but then you just get the isolator.

Then again you might get lucky and not have noise even without one so I'd for sure give it a try.

 

Just make sure there are no wiring errors. Plus goes to plus, minus to minus, no shorts anywhere (including the signal wires) and so on. Check each connection before turning on the power and you're fine.

 

--

Mikko

[Tom B]

One of the most important reasons why you need ISOLATION leads is to protect your audio device, which does not like having its audio output connected to its own negative/ground/earth.

 

As ALL Autocom audio inputs have common ground (earth) in relation to its power supply (our black power wire that goes to your bike battery) this is important to help reduce undesirable noise pick up from audio leads used on a bike.

 

If your Autocom device is bike powered (also to the bikes negative terminal) then if you use a standard wired audio lead between your Audio device audio output and your Autocom audio input, you are basically connecting your audio devices audio output to its own power supplies negative, which can and in most cases will blow your audio devices output amplifier. Usually before you burn your audio amplifier up, it will moan and grown and often squeal and complain which is what is often heard and reported.

 

So in order to protect from this you use an ISOLATING audio transformer built into your audio lead so that it allows AC signals to pass but not DC power.

 

Not all audio devices have independent earths for their audio outputs but those that do MUST be used with isolated leads if BOTH the Autocom and audio device are bike powered.

 

If either the Autocom or audio device is used on its own batteries then that device has its own independent and so isolated power supply and so standard leads can be used.

 

Hope that helps explain what its all about!

 

EX-Autocom UK Tom

[Tom B]

It’s all about DC decoupling.

 

You SHOULD check with the manufacturer of your audio device to see if it is OK to connect the audio devices audio output (neg) to its own power earth. In MOST cases (these days) it is NOT!

 

Older audio products (say 20 or so years ago) tended to work on higher voltages (typically 6 or 9 volts) and in many cases had common earths for both the audio output (negative) and power supply earth/negative.

 

Modern audio amplifiers are designed to work on much lower power/voltage (1.5 or 3 volts for example) and so to typically develop more audio power at lower supply voltage they now have independent earth audio outputs and SO MUST NOT BE EARTHED (via a standard lead to something like an Autocom which has common earth audio inputs (relative to power earth)

 

If you do not wish to damage your expensive Garmin/IPod etc PLEASE use ISOLATION IF IN ANY DOUBT, or at least call the technical support for the audio device before risking blowing up your device, which WILL almost certainly invalidate any warranty.

 

I understand about the matter and care about my old customers, which is why I tell others about this. Some may think it was because I was Autocom and its all about making more profit.. Well I am not Autocom now and I am not making any profit from telling you this information.

 

Tom

 

[BmKev]

Thanks very much for your reply Tom, and for your concern for your old customers.

The details you gave were as I imagined, so I am glad I asked for confirmation before trying to connect witout the isolator.

I sincerely hope you have managed to make a new start after Autocom, and, maybe you could kindly continue to give us some of your pearls of wisdom from time to time. I imagine that the Autocom user community would be pretty well in the dark otherwise!

You're proud of your products and it shows!

I now have a choice between an isolation adaptor, battery power or Bluetooth.....

Thanks again

Kev