Klein & hummel ue-100/ue-1000 topology?
« on: March 23, 2018, 07:05:08 AM »
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!