Neumann PSVe summing amp - broadcast filter?

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adamasnan said:
Yes, the caps are 2.2uf. If that resistor on the board is R6 then what on the schematic says 47k, this is 2k2.

Does that help?
Can you be more precise? What is the value of R6, the one that goes to the non-inverting input of the opamp?
What is the value of the resistor on the daughter board?
The available info tends to indicate a cut-off frequency of about 30Hz with a 12dB/octave slope.
 
abbey road d enfer said:
Can you be more precise? What is the value of R6, the one that goes to the non-inverting input of the opamp?
What is the value of the resistor on the daughter board?
The available info tends to indicate a cut-off frequency of about 30Hz with a 12dB/octave slope.

OK I will try, thanks. BACK SOON
 
Hello - I draw out the circuit as best I could, maybe it's enough to determine what I can change. Please forgive the layout, I had to draw it as I saw it, but hope it reveals the filter

Many thanks for all your help!

 

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adamasnan said:
Hello - I draw out the circuit as best I could, maybe it's enough to determine what I can change. Please forgive the layout, I had to draw it as I saw it, but hope it reveals the filter

Many thanks for all your help!
I bet teh left hand side of the 2k7 goes between the two caps. At least, thet's where it should go.
So clearly, the designer's intention is to create a Sallen & Key 2nd-order HPF at 18Hz.
If the circuit is really how you've drawn it, it's a 1st-order HPF at 80Hz!
 

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