Klein & hummel ue-100/ue-1000 topology?

Hi all,

I posted this before in the drawing board, but I think it's more appropriate here.
I was wondering what the topology of the wonderfull K&H ue-100 and ue-1000 eq's is?
Schematic of the ue-100: http://www.gyraf.dk/schematics/KH_UE100_equalizer.pdf
Schematic of the ue-1000: http://www.gyraf.dk/schematics/KH_UE-1000.pdf

What i've found so far:
They exist of a few building blocks (baustein).
Baustein O is the input and output stage
Baustein N is the power supply
So far the easy stuff.

Baustein E is a high-pass filter. I think the topology is Sallen-key. With the switch 12db/24db/36db you select how many of them are in cascade. The lin/etz switch is a bypass filter. And with the freq switch the frequency is selected of all 3 filters in cascade at the same time.
Baustein F is a low-pass filter, with the same principles as above, but of course instead of a HPF a LPF.
Am i on the right track so far?

Baustein A is a high boost, B a low boost, C is the low mid, and D the high mid. But i don't have a clue what the topology of those is. Does anyone have an idea?

Thanks in advance!

I am working in re-drawing the DaveP schematics for the UE-100 Klein & Hummel, and see the topologies of all these 6 boards (A to F) in a more easily fashion. I would like to get some help in order to analyze electrically with its networks equations for these boards in order to determine the Transfer Functions Equations and look for its frequency performance.

Any comments?
opacheco