You'd really better have a True Color display, if you want to
look at every detail of the pictures on this page.
As a matter of fact, I found it easier to stick a drop of solder to a resistor or
a capacitor connected to the DACs' outputs, rather than directly soldering the
"tapping" wires on the chips' pins. At the same time, you avoid frying them
!
Here's a view of a portion of the card :
Overview of the card
The DACs are indicated and the location of the wires are circled.
Zooming in the area of interest :
Details about the audio outputs
The discrete components (resistors and capacitors) to which the wires are
soldered are :
FM L --> C120
FM R --> C121
WF L --> R43
WF R --> R47
The power was derived as follows :
Power derivation
The 7th ISA pin from the left is -12V and the 9th delivers +12V. I found it
easier to solder the wires to the capacitors a bit downstream, as circled in
the above picture (black=-12V, red=+12V).
The ground for all the additional circuitry was taken from the CD connector's
pin.
All you need now is to connect a pre-amp to all the wires sticking out from the
card.
Preliminary results
In addition to the output separation, WF's sound seems brighter than before.
I hope to provide some evidence for this later. The FM's output had a weird
behaviour : it had WF sounds in the background, i.e. there was a crosstalk. But
this crosstalk was not symmetric, i.e. there was no FM sound in the backgound
of the WF's sounds. To cure this situation, I cut the FM path right before the
original on-board pre-amp. This provided a clean FM sound BUT
because the WF's signal can no longer "leak" to the FM path, all the
WF's out is fed to the above pre-amp, resulting in an increase of input signal
: distorsions can be heard for some loud sounds. I insist on the fact that the
sound is clean when heard from the separated output. It becomes a problem when
trying to listen to it from the original outputs. This of course doesn't affect
the digital audio playback.
I hope you have enjoyed following this project so far. Just let me
know, be the answer positive or
negative.
Too ugly for you ? Then get back.
Did you miss the previous schematics ?
