K67 capsule mod for less high end

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Quote from Martin Schneider:

"The [k103] capsule design is a modification of the U87 capsule. It has an average rise of 2...3 dB in the treble between 5kHz and 15kHz (in the lower tolerance range of the published specs)."

https://repforums.prosoundweb.com/index.php?topic=27515.0

From Klaus experiment (same link) about exchanging TLM103 and U87 capsules I guess that their response is quite different (where and how much is the rise in treble of the neumann's k67/87?).
 
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I am not so sure TLM103 capsule was designed to have flatter response than kk67, because the origin of the TLM103 concept was to make a more affordable version of the TLM171. The TLM171 was a kk67 on a 170. (I’m aware of the later marketing that would often mention U87, but the above is still what happened regardless.)

Maybe they did reign it in some, but I wouldn’t assume it.
 
I tried my K103 in a C12style 12AY7 and cathode follower 12AT7 circuits and did not like them, too much midrange and not enough highs, but with an Ami M49 circuit (cardioid) is completly different :)

The donor mic is a MXL V77 with circuit modified into an AMI M49 circuit, K103, 5840 sylvania, Jensen DBE, 1uf siemens MKP. The psu stock voltage is a bit high (158v), that polarize the capsule at 74v, so will lower it to 60v.
 

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  • 98 MXL V77 5840 M49 circuit Jensen MKP K103.wav
    9.5 MB
That’s how I felt with Samar’s capsule (cardioid-only as the k103) in both the cathode-follower and 49c style, but it was a C37-type direction instead of the C12-type. The low end of Samar’s capsule in the 49c style is phenomenally huge and open. I wonder how the k103 would compare. Following Neumann style, I’d imagine much much more tight.
 
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