Replacing the original Panasonic radio

[DavidL]

My 944T came to me with its original Panasonic Alphatune radio/cassette and the 10 speaker option.
I wanted to change the head unit for something with a CD so I sourced a new Sony unit. Comparing the instructions for both old and new it seemed a relatively straight forward job to swap them.
13 common wires -
8 for the 4 corners/speakers
Aerial
Power antenna
Switched power
Permanent power
earth

They were even the same colour.
Performed the electrical connection swap and it works splendidly.
However as I have the 10 speaker option somewhere in the car is an extra amp. This was connected by a DIN plug to the old unit.
This I cannot connect to the new unit for several reasons, mainly centred on not knowing how!
Wire colours are not documented and the instructions for the old unit do not label the connections on the back of the unit where these extra wires connect
I have looked at the Porsche wiring diagram but that left me even more confused!

It seems to affect the rear base speakers as I have no fade control front to back and the sound is a little base light.

The new unit has 6 extra phono type connectors for external amps so in theory it is just a matter of getting the correct wires in the correct place but I'm reluctant to just use a trial and error approach for fear of damage.

So any suggestions?
Thanks in advance
David

[hotblack944]

Is this any use?

http://www.connact.com/~kgross/FAQ/944faqst.html

[DavidL]

Thanks Jim,
I've read through that once or twice before. It details what the M490 option is but really how it goes together.
I never had the graphic equaliser so I assume just the external amp. I just need to reattach it.