I wouldn't do it just for the heck of it. The Neumann engineers are pretty bright and knowledgeable people who know what they're doing. The TLM electronics and capsule are optimized for each other. I'm sure you'll get neither the TLM's low noise floor nor the U87's sound by exchanging the capsule.
BTW: The TLM103 has a single diaphragm capsule, the KK67/87 is a dual diaphragm capsule.
actually, there is a tlm around with this capsule. it is called tlm-171 and looks exactly like the 170, same housing and electronics. they didn't make a large production of that, 100 or so. but i'm glad to have one. but i wouldn't try to mod the 103 this way since it
a) dosn't have the electronics to make use of a dual-capsule and
b) has half a kk87 in it anyway, so why exchange it to another one?
The 103 capsule is not 1/2 of a k67. The 103 capsule has its own sound. I like the circuit design and build of the electronic board, looks like laser trimed deposited resistors on the ceramic? PCB a good comformal coating on the circuit parts and board.
are you sure about that the 103 does not have half a KK87? To compare the sound of the 103-capsule to the U87-capsule , you'd need to take out the capsule and test it inside of an U87, since the U87 has kind of EQ.
My 171 definetly sounds different than an U87 even if it has the same capsule. They also mention in the manual that the capsule has more presence which is not equalized in the 171 but in the U87.
So I think it's the same with the 103 that I used for a long time. To come closer to the U87-sound you need to damp some presence with an bell-filter. I think it's more the amplifier than the capsule that makes a different sound here.
To my knowledge the TLM capsule is its own design. Of course it's based on the KK87 design, but optimized for lower noise. Note that the dual diaphragm version of the TLM103, the relatively new TLM127 does not use a KK87 capsule but its own design also. You're right about the EQ thing, though.
Yes the 103 is not the same as a 1/2 k67/87. The pictures are of my 103 in the meta and I also have a real k67 capsule and have worked on a number of u87s and compared them to my 103. I believe someone "here" counted the front plate holes and even that number is different.
Once you take capsules apart and start to study them you find out almost ever thing makes a difference and alot of tests and builds of capsules must have happened to get the sound wanted.
I have not fully traced my 103s schematic but Dale has a fragment in a thread in the meta it appears the 103 does not have a filter network like the 87. It kind of looks like a cascoded fet "top" BJT "bottom" white follower type circuit.
I believe people should think of and use a 103 as a 103 it does seem to have its own sound.