More Audio Noise Help

[4INer]

I know this has been covered and I think I've read most of the posts concerning alternator whine and an autocom install. I've got the autocam pro avi and so far have just a ski fi XM connected to it. I have a lot of alternator noise. My connection is ground to the battery and power from the aux fuse in (left side fuse panel) via a T-Tap. I'm removing the autocom today to send it back to top gear accesories so they can modify the unit so that the music inputs from aux 2 and aux 3 will not go to 50% volume when I talk (or in my case sing along). They call this option 1. When it comes back I'd like to do a better job of installing it and hopefully get rid of the noise. I just recieved a Centech aux. fuse panel, and plan to connect it directly to the battery and use the previously mentioned T-Tap to the aux fuse to power a relay. Then I plan to connect all my audio devices to the fuse panel. Plans are for the XM, and then adding a Zumo, and possibly bike to bike. Anybody have a suggestion on what relay to use and where to buy it? Also should I use the battery ground or ground to the frame, and if so where? And finally for the electrically challenged side of me, do I need a noise filter, what kind, and where do I put it. Do I need one for each audio in device? I've looked at Navone's isolated power supply, but am not sure that 2 amps will power everything I plan to add, and his larger capacity supply is more than I want to spend right now.

 

[Blrfl]

If your gadgets are bike powered, you'll need to put ground loop isolators in the audio lines. These work great and are $18 a pop.

--Mark

 

[bcst1300]

Ground loop isolators are an aid and better than most filters but good wiring practices are also very helpful. Get the power for all your Audio sources from the same place and close to the battery this is one place where an added fuse box, relay controled, is a good idea Bring all the grounds back to the same point and don't ground in multiple places. Don't use the frame to ground. Take a big wire from the battery and add a ground strip. make all you power leads as short as practicable including the big wires off the battery to the ground strip and fuse box.
Next route all wires for signals and power away from the ignition coils or plug leads. Inside between the air box and the frame under the gas tank is not too bad. Bikes and cars are noisy places. there is little or any filtering on the alternator (except the battery). A noise filter can help but if you use one you will need to power all your audio gear including two way radios from the filtered side. Maybe a 30 amp filter feeding the fuses for the audio gear might be another way to accomplish that.
I know lots of members here will power the intercom at the tail lights and the radio at the Aux power and the radio somewhere else and use a bunch of audio isolators with acceptable results but single point gronding is still a proven advantage over random power sources.

 

[newbluest]

+1 BLRFL


I used that on my XM to Starcom connection......I can't believe I rode so long without adding that......

Go straight to Crutchfield I can totally attest to the ability of that $18 device to clean the noise out!

 

[Blrfl]

Ground loop isolators are an aid and better than most filters but good wiring practices are also very helpful. ... Bring all the grounds back to the same point and don't ground in multiple places.

The other half of the ground loop problem crops up when you run an audio cable between the gadget and the intercom. Those cables have a ground line in them which introduces extra paths to ground. So you can either build cables with only one side grounded or put in the isolators.

--Mark

 

[4INer]

Thanks for the info. I'll start by installing the fuse block off of the battery with a relay to shut the power to the fuse block on and off with the bike power. I will still need to locate a good relay for that. I know autocom sells one but it is fused and rated at something like 2 amps. I'll want to be able to carry enough to power anything that I may want to connect to the fuse block so any suggestions would be appreciated. Then I'll ground everything to the battery and put an isolator between all my gadgets and the autocom. I'll let you know how it goes. Thanks again.

 

[Blrfl]

The relays they sell at auto parts stores are cheap, plentiful and most carry 30+ Amps.

--Mark

 

[sandman]

Here's the one I used to power the Centech fuse block. It's rated higher than the fuse block and will carry the full load.


http://www.aerostich.com/catalog/US/20V-70A-Sealed-Relay-p-18313.html



Gordon

 

[MAC_JD]

If your gadgets are bike powered, you'll need to put ground loop isolators in the audio lines. These work great and are $18 a pop.

--Mark

Has anyone seen a ground loop isolator like this one that can be purchased locally?

JD

 

[Mellow]

Has anyone seen a ground loop isolator like this one that can be purchased locally?

JD

That looks like the one at http://www.electricalconnection.com/audio/filter-gli.htm you can probably get one at radio shack too, but might be more bulky..

 

[NCrider]

Be careful with relay placement and don't get a cheap one. Make sure you get one rated 2x the current you expect and SEALED. You don't want any moisture getting in it.

Relays can be a real source for noise.

Edit: I would use shielded cable for all my audio power connections, but that's just me being overly anal.

Make sure you "twist" all your power leads.