Re: [Tech - Audio]Popping Fuses and removing Alt whine

[Brett Van Sprewenburg <brett@netacc.net>]

Did you do the subfloor build in the trunk?  I just did that in the fall,
countersinking a pair of amps and a 12in Rockford Fosgate DVC in the
new trunk subfloor.

>Hi all,
>
>        Well, I finally got around to installing a pair of amps and a
>subwoofer to my 16v.  However, I need help from the electrical/stereo
>know-it-alls out there.  One, I keep blowing the five amp quick blow fuse on
>the back of the stereo (the stock Heidelberg IV) after about 30-40 minutes
>of playing the stereo.

What's happening is that your amps are loading down the outputs of radio,
presenting it with a difficult to drive load (not bad, just difficult). In
turn, the radio is drawing more current in an attempt to deliver the
goods to the amps...low frequencies (bass) will draw the most.  I would
suggest one of two things if you want to keep your current setup...consider
replacing the fuse with a slightly higher rated fuse, like 5.5 amps thin
wire quick blow.  Or, replace it with a 5 amp wound slow blow fuse.  The
latter will be much more resistive to quick high current draws (such as
fulfilling low frequency requirements) but will still blow at a sustained
greater then 5 amp draw or heaven forbid, a dead short.  I like the second
solution better.

> Two, I'm getting some annoying alternator whine.

You may have done something like what I did...I made the mistake of
running some low level amp RCA's too close to the heavy gauge amplifier
power feeds.  I'm getting some hum due to this, which I'm going to fix
by moving them apart in the spring.  You can try using a noise suppressor
on top of that, but it might be ground loop, which a positive feed line
noise suppressor will not fix.  There are several good 'how-to's and why'
that cover in car electrical noise to be found on the net.  If you want I'll
turn something up...probably should put it on scirocco.org... :)

later!

==Brett


>
>- Brad
>'86.5 Volkswagen Scirocco 16v
>'76 International Scout II

 \/  '84 Scirocco (ITB racer 2B) | "Hot VW's, take two home. They're small"
\/\/ '88 Scirocco 16v (Show), '92 Passat 16v (Winter+) | - brett@netacc.net

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