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Discussion Starter #1
I’ve installed the Autocom Active-Plus on my 05 wing. Everything on the Autocom side works fine.

Now I’m trying to connect the Wing’s radio to the Autocom Music input. I started by making a passive adaptor to connect the passenger headset pigtail directly to the autocom music input. This sort of worked (you can hear the music), but there is a loud buzzing even when the engine and radio are off.

So, next I made a Ground Loop Isolator, and put it between the headset and music input. This completely eliminated the buzzing/hissing and the music sounds loud and clear…

Until I crank the bike. When the bike is running I get some alternator whirring in the autocom headset. I’ve read all the posts about moving wires, adding shielding, cleaning grounds, ..etc, but I’m not having problems in the bike system or the autocom system independently. Just when they are linked together through the passenger headset.

I know Autocom makes an adaptor for exactly this (part 1343).

My question is does this adaptor completely eliminate the electrical alternator whirring sound, or will I still be chasing something else even after I lay down my $109.99 (plus shipping) for the adaptor?

If it does eliminate it, how does it do it?
 

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Hello again, Backwoods...

I had an Autocom system on my '02 BMW K12RS and also had alternator noise on audio sources.

The Rube Goldberg solution I came up with was this: Wired a 140W inverter to the battery. Then plugged a Radio Shack doodad that plugs into 120V and has a cigarette lighter output. Plugged the Autocom into the 12V outlet and Presto! Whine was gone...

Evidently going from 12V to 120V and back to 12V eliminated the interference...

I'm sure you will come up with something a little more elegant... :D


Stay safe,


Lance
 

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Hi Backwoods,

I have an Active Smart 7 system I brought over from my 2001 Roadstar. I used part number 1048 ($60) but much to my chagrin I have the alternator whine in my headset. I went with Fred H's installation of putting the unit in the CB area of the trunk.

I emailed Autocom about it and their only suggestion was to try moving the wires around. I need to try that next, it is a very annoying problem.

As Themobb solution using an inverter, I discovered this works in my van when I was using a portable DVD player to feed the TV and sound system in it.
 

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Sounds to me like you have a ground loop. I have the Autocom interface, and I have no whine or problems when using it.

Are you sure you got the lead connected in the right phase? It sort of sounds like maybe you have the wires reversed. The input lines are left +, left -, right + and right - If you get the polarity messed up it will cause all kinds of problems.

I think all the high dollar autocom adapter lead consists of is a couple small transformers that act as ground loop isolators. You should be able to do the same thing with a $20 Radio Shack ground loop isolator IF you have the polarities wired correctly.
 

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The Autocom unit itself and its' input cables (and filters) are very susceptible to RF generated by the bikes' wiring harness. You may need to experiment with different installation locations before finding the right location for you.

I had one installation that was noisy no matter where I attempted to install it. When I used the 9V battery adapter, the noise went away. It turned out that the power connection point that I had tapped it into on the ACC terminals on the side of the fuse block were very electrically noisy.

Powering the unit off an E/C power plate (which uses a relay to switch power directly from the battery) and using a clean ground from an E/C ground termination block solved the issues.
 

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Discussion Starter #6
Fred, I’m connecting to the Goldwing pigtail which has a common ground between the left and right speaker:



I’ve already added a Ground Loop Isolator which did remove all the buzzing/hissing I heard while the bike was off. Now I’m just trying to get rid of the alternator whirring.

This thread has been helpful. The consensus seem to be that it’s the power rather than the audio input that’s causing the problem. So I tried running the Autocom from a separate 12v battery. Sure enough that completely eliminated all the alternator noise.

Themobb, your solution worked because the 12v - 110v and/or the 110v - 12v inverter must have been isolated. So that would be just like running from a separate battery. So it looks like I’m on the same path as you after all.

Anyone know a good source for a really small 12v-12v isolated/regulated supply?
 

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If your noise goes away when you unplug the interface from the Autocom to the bike, then the noise is from a ground loop that has formed between the bikes audio system, the Autocom, and the charging system of the bike. You can break the ground loop in several places, either at the power source or at the interface with a ground loop isolator. But be warned, the ground loop isolator itself is nothing more than a large transformer, and it will act as a magnet to any RF that the ignition coils or alternator produce. You may have to position the ground loop isolator itself far away from any harnesses to keep it from picking up noise.

If the noise is always there when the Autocom is powered on, even with the interface disconnected, then it is noise on the power line.
 

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Discussion Starter #8
Fred, my understanding is the same as yours, but I can’t explain what I’m seeing. I made my GLI out of caps rather than a transformer and it does eliminate all the buzzing when the bike is off. My circuit is as follows:

-------||--------- Right
-------||--------- Left Goldwing headset pigtail
-------||--------- Ground
.01microF

It does block DC, but maybe that’s not sufficient for clean audio. When I unplug the music lead from the Autocom, the headset is completely quiet and all the other Autocom inputs work fine, so I would agree with you that the problem must be on that music interface.

However, when I leave the music lead plugged in, and power the Autocom from a separate battery, there is no whirring and the music comes through clearly.

It seems like if the whirring is caused by RF induction then I would hear it no matter how I power the Autocom.
 

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backwoods said:
Fred, my understanding is the same as yours, but I can’t explain what I’m seeing. I made my GLI out of caps rather than a transformer and it does eliminate all the buzzing when the bike is off.
I think you will have better luck with an audio transformer instead of a capacitor.
 

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Discussion Starter #10
Fred, you are correct.

I replaced the caps with two audio isolation transformers from Radio Shack (about $3.50 each). Now the music comes through clearly with no buzzing, hissing, or whirring. Just clear music.

I should have thought about it more before just using what I had laying around. :) Even through the caps block the DC part of the Ground Loop they pass ALL AC, both the signal and noise.

The transformers also block most of the common-mode noise. Since the audio wires run along the same path, they pick up about the same noise on both positive and ground leads, so the transformers are very effective at removing it.

So, now my $10 adaptor allows the Autocom to hear any output that originally came to the bike’s built-in headset, just like the +$100 Autocom adaptor. Though, to be fair, my solution supports output only, while the Autocom also supports microphone input for the CB function.
 
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