K47 capsules roll off

[oscarhuang]

I have to say with flat circuit I don’t like k47 and k67. I build u87 and u67 point to point and I love it. I used rk87 capsule for them. I also tried Maiku k87 for u87 circuit but Maiku k87 is not fit for it. Maiku k87 is much flatter response than original k87. Because I did a schoeps with HF boost and I found the sound is what I wanted. So I made this post to see if anyone have a better idea to made a HF boost for tube circuit.

 

[RuudNL]

Okay, please explain where the filter is?

There is no HF filter! This was probably a prototype or a development model. (Schematic 00-00-00).
It is the same with some of the stereo microphones that Neumann has produced; they used a K67-like microphone capsule without any form of de-emphasis. The idea was that at a larger distance the friction between the soundwaves and the air molecules would already cause a HF Roll-off.
In the schematic shown, the tertiary winding only provides a wide band feedback.
The tertiary winding is terminated with R18 and is in series with R19/R20. This signal is fed to the backplate of the capsule, providing wide band feedback.
In later versions, C19 is responsible for a frequency dependent feedback.

 

[McIrish]

Not to start any argument at all but... If the OP does not like a K47 type capsule, why would anyone recommend an M7? If the K47 is too dark for his purposes, then the M7 most definitely will be too. While not identical in sound, they are very much in the same family. A K67 or a CK12 would be brighter. The K67 might be horrible without the right circuit to tame the HF. Maybe the OP has used many of the less costly condenser mics coming out of China and likes that high frequency push? I personally would rather add a bunch of 10K to a U47 and use an overly bright mic and try to tame harshness later. I've never been successful with that.