Geez dude, that was hard on my ears. I couldn't even tell WHAT the heck I
was hearing, it sounded like a loud roar. Whine? Huh? It seemed to be the
only sample there so I ASSUME I was listening to what you intended us to
hear but I could make out no "whine", unless you want to call that loud roar
a whine.
Frankly, it's easier to just tell you what a ground-loop will sound like and
you can make the determination yourself. A ground loop typically sounds
like a high pitch whine that comes over your system and the whine changes in
pitch along with the RPM's of your engine.
The changing in pitch along with the RPM's is really the tell-tale sign of a
ground loop problem and if your whine DOES NOT change in pitch to match the
RPM's then it is probably NOT a ground loop.
However, if it does, then you indeed have a ground loop problem. In a
nutshell, ground loops are caused by differences in negative voltage
potentials between the different components of your system. These
differences are nulled out over the RCA's that connect them together and is
where the noise comes from. The reason it changes with the car's RPM's is
because as the alternator produces more or less current, both the positive
AND the negative electrical potential of the car changes, in other words the
grounds get closer together and further away as RPM's change and the car's
entire electrical potentials change and this getting closer and farther away
is what causes the changing of pitch.
How do you get rid of alternator whine? Well, for me, the VERY BEST tried
and true method which I have employed for over 20 years is connecting ALL
the grounds of your system together (head-unit, amps, processors, ect.) with
large gauge cable, like 8 or 4 gauge. You can simply ADD this to your
existing ground cables (you don't need to rip out what you already have).
What you accomplish by doing this is assuring that all grounds see the exact
same negative potential and presto, no more ground loops.
Now in theory, you shouldn't have to do this as the car's chassis (what most
people use as their grounds) is so large (larger than any gauge of wire)
that ALL points on the chassis SHOULD have precisly the same negative
potential. And for many cars I've owned and worked on this has often been
the case. But, in practice, it is simply a fact that different spots on a
car's chassis do indeed hold differing negative potentials. It's not always
clear why (different thickness in metals, different alloys that conduct
electricity a little different, ect.). So, again, the best way to
absolutely fix the problem is connecting all the grounds together with large
gauge copper wire, and any residual differences in ground potential will
null themselves out over this large copper wire, rather than your very thin
RCA wire.
This has ALWAYS fixed any ground-loop problem with any car I have ever
worked on. It is, for me anyway, been a sure fire fix. If that sounds like
a little too much hassle, however, Radio Shack and others sell ground-loop
isolators that connect between the RCA's and I know those always work well
and, as far as I can tell, do not effect the sound quality. They sell for
around $20 I think and are a quick and easy fix.
Anyway, hope this helps.
MOSFET
"sustain" wrote in message
...
Could This Whine Be Caused By a Ground Loop?
The link below is to an MP3 file lasting only a few seconds (158 kb).
http://www.zshare.net/audio/605114385f1fe180/
Thanks.