Xref: utzoo rec.audio:7976 sci.electronics:3680
Path: utzoo!utgpu!water!watmath!clyde!att!icus!limbic!gil
From: gil@limbic.UUCP (Gil Kloepfer Jr.)
Newsgroups: rec.audio,sci.electronics
Subject: Re: Sony D-10 through car amp
Summary: Try this, it might work...
Keywords: motor noise (CD motor)
Message-ID: <183@limbic.UUCP>
Date: 23 Aug 88 05:22:42 GMT
References: <2253@uhccux.uhcc.hawaii.edu> <15911@apple.Apple.COM>
Reply-To: gil@limbic.UUCP (Gil Kloepfer Jr.)
Distribution: na
Organization: ICUS Software Systems, Islip, NY
Lines: 35

In article <15911@apple.Apple.COM> lemke@apple.com.UUCP (Steve Lemke) writes:
|>In article <2253@uhccux.uhcc.hawaii.edu> taro@uhccux.uhcc.hawaii.edu (Taro Nobusawa) writes:
|>>...If I unplug the amp input from
|>>the D-10 headphon, I don't get any noise and also obviously no music.  If I
|>>run the D-10 off its own battery, I get no noise and good music.  The noise is
|>If anyone's come up with a solution to
|>this problem (which doesn't seem to be brand-dependant!), I'd love to hear
|>about it!!

Okay, here's my idea.  Please keep in mind that I'm a mere computer programmer
by day, digital electronics person by night.  I have an idea on what can be
done to fix the problem.

If you can dig up a set of 2 audio transformers (two of the same), try 
connecting the primary of each transformer between ground and the audio
output on the CD player side, and connecting the secondaries between the
auto ground and the audio input to the car stereo.  The transformers will
isolate the two grounds.

I have NO idea what kind of impedience the primary/secondary should be, but
I think a 1:1 ratio (ie. isolation transformer) is what is needed.

I looked at my Sony D-5 player, and if you look at the power connector, you
will see that (at least in mine) the "+" side is the outer conductor, which is
generally connected to the device's chassis and audio ground.  Why Sony made
a positive ground unit is beyond me, but it seems like they did.

I would appreciate knowledgable people elaborating on this idea...

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