From: Chris Muth <rockbox_at_muth.cc>
Date: Wed, 14 Jan 2004 20:59:11 -0600

How much of an electrical engineer are you?

I modified the cassette deck in my Dodge Intrepid to allow for line in.
The cassette deck controller board was connected to the main board in the radio with a
10 pin (IDE like) cable. One wire was ground, one was left, and another one was right.
Unfortunately the left and right were were fluctuating around 10 volts and not 0 volts like
the ear out of the jukebox. I used two (one for left and one for right) 25V/3300uF caps to
couple the ~0 volt audio onto the ~10 volt audio lines. I clipped the left and right lines coming
from the cassette deck after I had fully scoped the cable and knew what each wire was. To keep
the caps from charging to the 10 volts, I put 100Kohm pull down resistors on the line in
side of the caps.

It seems to need a minute or so after power on before I plug the JB in, or the audio will become rather bad.
It had lots of distortion, static and such. I think what happens is that the whole cap gets driven to 10
volts and the pull down resistors slowly pull the low side of the cap back to zero. After that, the audio
is be great. I think I should have use smaller pull down resistors on the low side of the cap
to more firmly pull it low (this is what the JB does and messes up the audio), and the proper pull up
resistors on the high side to keep the cap from being pulled to ground (opposite of what happens now)
by the pull downs. Though, attaching the high side of the audio lines to the power rail (via resistors)
could have been problematic. As it is now it works great, I just have to wait a minute before I can use it.

-Chris

On 1/14/04 at 7:32 PM Glenn Ervin at Home wrote:

>Hi,
>I am now using a Ford Taurus with a stereo that allows for a CD player to
>be
>plugged into it, I think the connection might be in the trunk.
>But what I am wondering is if anyone knows if there is a way to connect an
>audio source, like my JBR into the stereo directly, such as in the back of
>the stereo.
>I would rather not use one of those cassette devices, as they are a hassle,
>and after a while, they ware out.
>Thanks.
>
>Glenn.
Received on 2004-01-15