Re: Stereo Noise Fixed! Thanks

[steveb@newkla.kla.com]

> First suggestion from list was to improve grounding location. Got extreme on
> this one and grounded head unit to the ENGINE BLOCK. Result? No change. 
> 
... not a surprise to me.  If you want to minimize the coupled noise in the 
ground you need to connect all of the devices to a single ground point ... 
and that ground point should be as close to the BATTERY as is possible.

> Finally, yesterday, went to Radio Shack at advice of many, and purchased a
> GROUND LOOP ISOLATOR. $14.99. This hooks up between RCA patch cables. Well,
> tried it up front, between deck and EQ. Sadly, no change. Then tried it in
> back between one set of RCA's to amp at the amp. IT WORKS LIKE A CHARM!
> Unbelievable. No whine. Seems like the sound is cleaner, too. Such a simple
> install, to boot.
> 
I tried one of these on my QTC when I was rewiring the stereo, and much to
my surprise the buzzing actually got worse!  The strategy that worked the best 
for me was to run heavy gauge power and ground leads directly from the bat-
tery to the stereo head.  I rigged a relay so that the +12 was switched on 
and off by inserting the key in the ignition switch (using the same contact 
that makes the warning bell ring when you open the door with the key in the 
ignition switch).  I still can hear a small amount of whine in the rear 
speakers if I have the volume turned way up and it is a quiet passage of 
music, but it is acceptable.  BTW - the RS isolators use a transformer to 
isolate the two circuits ... if anything that should adversely affect the 
frequency response of the system (i.e. you should have a more faithful 
reproduction without the isolator).

Don't forget the fuses if you run any direct wiring from the battery!

Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)