Looking for Behringer B-5 schematic

[molke]

I have made my own, which goes very close to it and holds the same result. Since I fear scrambing, I include the text as *.pdf.

If you don’t like the theoretical calculations of Holger Pastillé, how do you explain the measurement results (for example, in Section 4 of the preprint version above), where the harmonics increase with an additional parallel capacitance?

For a short formal question to your document, I attached a PDF as well.

 

[Bert37]

Thank you for rising up that question. I notice that there is a mistake in my notations as the powers of k were missing after the equal sign. See pdf. Sorry for that.
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To the first remark: I think it is not up to me to evaluate why the practical measurements do not correspond to theory (which was already given in a similar form referenced by Jan) but the other way round. I also believe the major suppliers of high quality condenser microphones would not run that trace if practice contradicts the effect. Such disagreement to theory should always be suspicion for weak points in the measurement setup.

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[molke]

Thank you for the clarification.

Such disagreement to theory should always be suspicion for weak points in the measurement setup.

… or in the contradicting theory?

 

[Bert37]

It's everyone's choice to believe in either ! See Einstein !

 

[LevinGuitar]

I propose to eliminate the strange output network (R1, R2, R4, C4) completely. Instead, there should a similar transistor as Q1 hooked up with its base also via 150k at the crossing of R12, R5, C10 exactly as Q1, but no signal feed (blocking capacitor to ground). This transistor would only act as a bleeding path for XLR-2, carrying no signal. Both emitters may be connected directly or via low value resistors to XLR-3 and XLR-2. The cost of an additional transistor may well be paid off by the loss of C4 ! The gain in output swing and according reduction in distorsion may be considerable !

Bert

I just tried that in one of my B5 and it works and sound a bit nicer, more lively. After removing C4, C3, R1 and R2, there are enough space inside to fit the new 2N5401. I left the original R4 and placed a jumper instead of C4.

I wonder if a opposite diode to D1 is nedeed between Collector and Emitter of the new transistor.

 

[jp8]

I wonder if a opposite diode to D1 is nedeed between Collector and Emitter of the new transistor.

If you're 200% sure you will never short the signal wires to ground, as could happen in e.g. jack plug patch bays, then the diode can be left out. Else, put it in.

Jan