Differences between Blaupunkt Koln 'V' & later power amplifiers

[Mende]

I don't know whether this will help as I can't identify the exact model but there is a circuit diagram for a Köln 1964 here which would fit your date criterion:
http://www.4tubes.com/SCHEMATICS/Radios/...n-1964.jpg
If there is any problem with umlauts you'll find it here in the appropriate alphabetical place.
http://www.4tubes.com/SCHEMATICS/Radios/...index_img/

There's a KölnG from 1958 here:
http://radio.mijnwijkapp.nl/Blaupunkt_KolnG.pdf
It's a bit early but might be interesting.

Various other Blaupunkts here:
http://www.nvhr.nl/gfgf/schema.asp?Merk=Blaupunkt&Zoeken=exact&isSubmitted=yes