Mic modding - help a newbie out!! K47 & C12 options potentially

[rookiemodder]

Hi all,

I've now got a couple of Behringer B2 Pro's. Great mic for non-sibilant baritone's IMHO so going to keep one in stock form. The other one I am looking to put a K47 kind of capsule in (maybe keep as dual-diaphragm?) Anyone made any frequency graphs in similar 'flat circuit' mic's? Thinking for extra quality I should look at 3U or Maiku. Heard Rayking is decent on a budget but can only source Getwin here I think - any differences?

Also, I have an Aston Origin but think something is wrong with it as it's noticeably less sensitive than the Behringer's though the relevant specs would suggest this shouldn't be the case. I'm attempting to keep in in a wrapped bag with silica gel to see if that improves the situation. Else would a capsule replacement be the cure? I think I would try a C12 style, maybe even push for a Tim Campbell? But does anyone know about polarisation compatibility, etc? Should I try and measure something to make sure the circuit isn't damaging capsule(s)?

EDIT - I think I may have to check the impedance switch on my preamp, have a feeling I tried low impedance and the Origin is double the impedance of the B2 Pro so would be affected by this more in level, surely.

Thanks in advance