Ferrari Mailing List: Re: Need help with stereo in Ferrari

[Doug and Terri Anderson (dnt]

I recently attended a diagnostics OBD II class covering the new onboard 
communications protocol called CAN (Controller Area Network). For 2008, CAN 
is used on all U.S. passenger cars and light truck.

Found a break in a wire?  Want to repair it?  This touchy system requires an 
exact number of twists per inch, same length and gauge wires and don't even 
think about splicing unless you hold an ME in advanced auto electronics.

My head hurt after that séance.  heh heh
DOUG
(does electricity flow over or through a conductor?)

----- Original Message ----- 
From: "Charles Perry" <charles [at] carolina-sound.com>
To: "DOUG" <dnt [at] dock.net>
Cc: "The FerrariList" <ferrari [at] ferrarilist.com>
Sent: Sunday, March 08, 2009 8:42 AM
Subject: Re: [Ferrari] Need help with stereo in Ferrari


> Just for everyone's future reference, the basic problem with all car
> audio systems with respect to noise is that car audio is unbalanced by
> design (meaning the music's electrical return path and ground are the
> same conductor). A properly balanced system (most pro-audio equipment)
> uses three conductors (positive, negative, ground), rather than an RCA
> line's two conductors (positive, negative/ground).
>
> The signifigance is that the "shield" of RCA wires is not actually a
> shield since it is carrying the music signal. That is also why it is so
> prone to picking up noise. This is why things like Monster Cable
> interconnects are complete wastes of money. Extra layers of shielding
> are, by definition, not shielding in car audio, nor in the vast majority
> of home audio (anything with RCA connectors).
>
> This is also the hint of truth in Jeff's suggestion for using network
> cable. Network cables are balanced and use their twist as part of a
> noise rejection scheme (same as balanced pro-audio cables). This works
> in networks due to the balanced electronics on both ends. Using network
> cable for car audio will not give you the same benefits because the
> electronics at both ends are unbalanced. It will still work, but no
> better or worse than regular RCA cables.
>
> In the 90's Rockford Fosgate tried to introduce balanced audio into the
> car stereo world in their upper-end lines but it was expensive and
> poorly understood and did not catch on.
>
> My current favorite scheme is using fiber-optics as interconnects, but
> this requires equipment that is designed for that, which is expensive.
>
> -- charles
>
>
>
> -----Original Message-----
> From: Jeff Greenfield [mailto:coyote [at] acme-ltd.com]
> Sent: Saturday, March 07, 2009 10:24 PM
> To: Charles Perry
> Cc: 'The FerrariList'
> Subject: Re: [Ferrari] Need help with stereo in Ferrari
>
> Three things come to mind.
>
> One is that you are picking up RF noise from through your RCA cables.
> Believe it or not, I have read that the best thing to use for to connect
> components in a car is CAT 5 Network Cable. I've used this (making my
> own
> cables) on the last few installs I've done and have had no interference
> problems at all. Sometimes the shielding in shielded cables will
> actually pick up noise.
>
> The other possibility is that you are having a ground loop problem. This
> occurs due to a very small difference in potential (essentially voltage)
> when components are grounded at different points on a cars chassis. You
> can try a ground loop isolator to see if it reduces or eliminates the
> noise.
>
> One last thought, if your sub uses speaker level inputs from your head
> unit, sometimes this causes random popping usually when switched on and
> off. If there is any way you can use line level inputs to the sub (I
> assume you are using a sub that has its own amp) you would be much
> better off.
>
> Jeff
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