[s-cars] Bose system pops with Alpine deck

[Andrew Beckert]

You need to run your line-outs through ground loop isolators into the Metra
harness.  Most aftermarket stereos use floating grounds as they have
individual amps for each speaker.  The Audi/Bose is designed to use a common
ground, so whenever you change tracks or turn your new HU on, the audio
would be grounded using the common ground, but with the aftermarket unit a
floating ground is used with a potential differential from common ground
(what the Bose amps are using for power), and this causes the capacitors in
the Bose amps to discharge creating that cool popping sound.  At least
that's how it was explained to me.  Here's a Crutchfield link that goes into
some more detail:

http://www.crutchfield.com/S-MbhgVdg05NA/tech/kb350.html

ymmv,
Andrew

On Thu, May 1, 2008 at 12:30 AM, <calvinlc at earthlink.net> wrote:

> That is a GREAT way to describe it!  The tumor in my car known as
> Bose.....That's great!
> --Calvin
>
>
> -----Original Message-----
> From: Eric Phillips [mailto:gcmschemist at gmail.com]
> Sent: Wednesday, April 30, 2008 10:05 PM
> To: calvinlc at earthlink.net
> Cc: john at johncleirigh.com; s-car-list at audifans.com
> Subject: Re: [s-cars] Bose system pops with Alpine deck
>
>
> Here's a funny story:
>
> When I first got my Traffic Pro, I used its line-outs to go to the
> Bose stuff.  Popping on shut-down, just like the OEM head unit.  I
> tried capacitors in-line.  Nope.  Noise suppressors.  No dice.
>
> So, I purchased a line level converter.  Well, it goes both ways -
> line-out to speaker level, and speaker level to line-out, depending on
> what way you hook it up.
>
> I used the speaker outputs on the Traffic Pro as my "in" and line
> level as my "out" - no popping.
>
> The Bose crap is weird.  Maybe some day, I'll do some surgery and
> completely remove the tumor in my car known as "Bose".
>
> Eric
>
> On Wed, Apr 30, 2008 at 8:44 PM,  <calvinlc at earthlink.net> wrote:
> > Eric,
> >
> >  I am feeding the Bose system with the Line-Outs from the Alpine and it
> does
> >  NOT eliminate the popping.
> >
> >  --Calvin
> >
> >
> >
> >
> >  -----Original Message-----
> >  From: s-car-list-bounces at audifans.com
> >  [mailto:s-car-list-bounces at audifans.com]On Behalf Of john cléirigh
> >  Sent: Wednesday, April 30, 2008 6:30 PM
> >  To: Eric Phillips
> >  Cc: s-car-list at audifans.com
> >  Subject: Re: [s-cars] Bose system pops with Alpine deck
> >
> >
> >  Indeed Calvin and Eric!  You're both right about my response.  I should
> >  have offered my experience as a data point to suggest the remote amps
> are
> >  registering the power-down as a thunk through the speakers and so any
> >  aftermarket head unit with a non-filtered (non-balun'd) output will
> likely
> >  also overload the front end of the amps.  Thanks.
> >
> >  I think the Alpine deck should feed the Bose amps from the RCA jacks
> and
> >  not the speaker harness.  I'm sure that would eliminate the thunk
> because
> >  the amps are looking for a line level input.
> >  --
> >  john cléirigh | Boulder
> >
> >  On Thu, May 1, 2008 12:11 am, Eric Phillips wrote:
> >  >> The worn rotary switch and the amps popping or thumping are two
> >  >> separate issues, IMO.
> >  >>
> >  >> I, too, had the thumping on DeltaCC power-off (only with rotary knob
> -
> >  >> the ignition wasn't in the circuit.)
> >  >>
> >  >> Then I put in my Traffic Pro, and lo and behold - same problem on
> >  >> powerdown.  OK, so then I put a device in-line - a speaker -> line
> out
> >  >> converter.  No more popping.  :)
> >  >>
> >  >> I am very happy with the way it all turned out.  I would have
> >  >> preferred to stick with Audi stuff - like a Concert I as the head
> unit
> >  >> - to avoid all the electrical gymnastics it took to make the Traffic
> >  >> Pro work.
> >  >>
> >  >> Eric
>
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