Re: [tech] Radio/ Amp

["mark hausler" <greenchester@scirocco.zzn.com>]

From: "Chris Chemidlin" <spredhaus@hotmail.com>

Hey kids...

After doing some motor work to my car, I thought Id treat myself and
install a radio. Ive run into a big noise.  Here's the setup.

1)Sony 'knob style' radio /cassette------(+ & - are factory hookups, I 
have the switched and constant power leads hooked together.)

2)4x6 'chrystal' speakers (Mark mages  hand-me-downs...Thanks!)  that
don't make any useful sounds....(powered by radio power)

3)small power amp (20x2) with RCA's and remote switch running on pass
side of car, and the power running on drivers side to fusebox constant 
power.

4)5.25 Phase-Linear speakers powered by amp.

OK, here's the bad symptoms.

when I turn the radio on (car off), the amp switches on and sounds fine.
When I turn the radio on (car on), the amp has car noise (alt, brake
lights, horn) at one particular volume- it doesn't change when I turn it
up.  the radio still works fine, but big noise sucks...
If I unplug the RCAs at the amp and plug in a portable CD player it
sounds fine---car on or off.

Now the amp seems to be grounded by the mounting screws--when I hook a  
ground to the chassis or to the battery, the noise is still there.

Im no stereo guru, but I like to pretend that I can complete a simple
circut! Should I try to run the power and ground to the ones the radio 
is hooked to?  question#2)  can I run the 'switch' wire from the amp to
the FUBA to power it? Right now the 'pwr ant' lead off the radio
switches the amp.


thanks for any insight!




Chris,

It sounds like you have most things in order. The one thing that stands out to me is you have the amp Pos lead to the fuse box. I know it is not the most powerful amp, but I would wire the Pos straight to the Battery (with in-line fuse). Also ground the amp with a wire, not mounting screws. Also make sure the speaker wires from the amp do not run next to the power cable.

Hope that helps




mark hausler
'81 scirocco s
'94 toyo 4x4
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