Kevin McMurtrie wrote:
In article .com,
wrote:
I have a laptop in my trunk which I'm using as an MP3 player. Up
until
recently I used a cassette adaptor to pipe the sound into my 2000
Passat's factory head unit. I decided to upgrade the sound quality
a
bit, and bought a PIE VW-AUX (a device which converts the unused CD
Changer connector in my trunk into an auxiliary input) adaptor and
now
have the audio from the laptop running through it to the head unit.
Everything works like a charm as long as the laptop is running off
its
own internal battery. If I select CD1 on the head unit, I can hear
nice clean(ish) audio from the laptop.
When I have the laptop connected to the power inverter (plugged
into
the cigarette lighter socket in the trunk), though, I get this
really
loud buzzing/humming sound coming through the speakers (lound
enough to
almost drown out the music completely). It doesn't matter whether
the
laptop is on or not - as long as its plugged into the car battery
through the inverter, I get a loud humming sound when the CD
changer is
selected on the head unit. About 5% of the time, the humming sound
might go away for a little while, but always comes back again.
[snip]
You probably have one of the many piece-of-crap inverters that have a
live neutral. An audio ground loop eliminator is meant to block a
volt
or two of ripple, not a spiky 60V square wave.
There are solutions -
1) Find a quality, true sine wave, AC inverter with an isolated
output.
[snip]
I thought I'd post a follow-up with the "final solution". Kevin was
correct: the problem was with the power inverters. True sine wave
inverters are massively expensive, but there's a cheaper (and totally
adequate solution).
While doing research, I came across a product made by a company named
Vector. They make a line of inverters (MAXX SST) that advertise ("New
Noise-Free Technology"). I bought the 225 WATT model (TVEC034) at the
local Target for less than $30 and it has almost completely solved my
electrical noise problem (if I gun the volume up to the max I can hear
a very soft buzzing, but I'd never have the volume anywhere near that
high when listening to music).
My "only" complaint about the unit is that it's cooling fan is pretty
loud (loud enough that I can hear it in the trunk of my Passat sedan
when I'm sitting at a stop light), but I can live with that! :-)