Autocom - noise in music output

[Tomcat]

Hope someone with Autocom expertise can give me some advice on this... I'd call Autocom but they won't be open until Tuesday and I'm an impatient bugger

I've just fitted an Autocom Active7, powered from the diagnostic socket, and with the earth taken back to the battery. I've velcroed the unit to the side of the airbox, under the ali panel at the side of the tank. So far so neat !

I'm using an HP iPAQ PDA as a GPS unit (has a compact flash GPS receiver) and as an MP3 player. The sound output from the iPAQ is plugged into the music socket on the Active7. The problem comes when I power the iPAQ from the bike. I'm using a bit of a lash-up, which involves plugging a ciggie lighter power adaptor into the accessory power socket on the GS, (via another adaptor which provides a ciggie lighter socket). When the iPAQ is plugged into the bike power there is a lot of electronic noise through the Active7 headphones which disappears when the iPAQ is running on its internal battery. I don't think its just an earth loop - there is some noise if only the earth side of the power adaptor is connected to bike earth, but its worse when the power adaptor is fully connected (Hope this bit makes sense).

So the questions are - do I need Autocom's stereo isolation lead (part 64)? Would I be better off getting the isolated adaptor lead for GPS and phone (part 57)? Or is the problem caused by taking the Autocom power and iPAQ power from two different locations in the wiring? Oh, and BTW what is the difference between the Active7 phone socket and the music socket - I can hear the iPAQ sound through both?

Thanks in advance for any advice
TC

 

[Mick_rw]

You will need the isolator

Hope someone with Autocom expertise can give me some advice on this... I'd call Autocom but they won't be open until Tuesday and I'm an impatient bugger

I've just fitted an Autocom Active7, powered from the diagnostic socket, and with the earth taken back to the battery. I've velcroed the unit to the side of the airbox, under the ali panel at the side of the tank. So far so neat !

I'm using an HP iPAQ PDA as a GPS unit (has a compact flash GPS receiver) and as an MP3 player. The sound output from the iPAQ is plugged into the music socket on the Active7. The problem comes when I power the iPAQ from the bike. I'm using a bit of a lash-up, which involves plugging a ciggie lighter power adaptor into the accessory power socket on the GS, (via another adaptor which provides a ciggie lighter socket). When the iPAQ is plugged into the bike power there is a lot of electronic noise through the Active7 headphones which disappears when the iPAQ is running on its internal battery. I don't think its just an earth loop - there is some noise if only the earth side of the power adaptor is connected to bike earth, but its worse when the power adaptor is fully connected (Hope this bit makes sense).

So the questions are - do I need Autocom's stereo isolation lead (part 64)? Would I be better off getting the isolated adaptor lead for GPS and phone (part 57)? Or is the problem caused by taking the Autocom power and iPAQ power from two different locations in the wiring? Oh, and BTW what is the difference between the Active7 phone socket and the music socket - I can hear the iPAQ sound through both?

Thanks in advance for any advice
TC

I had the same problem with my GPS audio, SPIII, connected directly to the Autocom 7, ok on internal batteries but lots of noise when running from the bike battery. Fitted the Isolater and it worked perfectly after that. I used Part 174 which is specific to SPIII. then changed it to Part 57 later on to add a phone. Both work fine. Hope that is of some help.

Mick

 

[Pukmeister]

My BMW Nav2 (same as Garmin 2610) did this when my Autocom Pro7 sport was bike powered (no prob on batts). Whenever the GPS spoke instructions, I just got electrical noise instead.

Turned out I needed an isolator block from Autocom (red/black inline box of tricks) which has cured it. Something to do with 'ghost earthing' I was told (???).

 

[GSrich]

You will need a Parts 57 and 170 to get yourself sorted. The problem is due to you having a thing called a ground loop which when you bike power your GPS the interface lead from your GPS into your system is picking up the bikes interference and being carried through to your system. Once the lead contains isolation the problem will be gone, problem solved.

 

[beemerboy9]

Part 57 contains two isolating circuits I think, one for the GPS (a one-way device) and one for the phone (two-way - send and receive). So you plug the 57 ( its about 6" long with the plug lead) directly into the music port of the Autocom.
All you then need is a lead to go from the the PDA (3.5mm stereo?) output to the "A" input part 57 stereo input. Part 60 (1.5m) or part 61 (2m) should do the trick as Part 170 is for GPS with mono audio output.
When you add the phone you'll need another suitable lead to reach the "B" input on part 57.
Hope this helps.

 

[beemerboy9]

Part 57 contains two isolating circuits I think, one for the GPS (a one-way device) and one for the phone (two-way - send and receive). So you plug the 57 ( its about 6" long with the plug lead) directly into the music port of the Autocom.
All you then need is a lead to go from the the PDA (3.5mm stereo?) output to the "A" input part 57 stereo input. Part 60 (1.5m) or part 61 (2m) should do the trick as Part 170 is for GPS with mono audio output.
When you add the phone you'll need another suitable lead to reach the "B" input on part 57.
Hope this helps.

I've just had another look at my installation which actually has separate GPS, music & phone units.
Since your PDA and MP3 are presumably one and the same output, you should find part 64 - isolated music lead - will remove the noise. Plug this into the music port on the Active-7.
When you add a phone this can be plugged into the Aux port. You should not require isolation for the phone when it runs off batteries.
I believe on the Active-7 that when you speak the music is muted.

Sorry about the previous, slightly dud, information.

 

[Tomcat]

Thanks

Thanks to everyone for the replies. Looks like I need to spend a bit more with Autocom...

TC