Can you fit kk47 capsule in a u87?

Gentlemen,

I have a u87 with a collapsing capsule. I also have a good kk47 capsule with no home. I also am considering an Inner tube kit. Will the kk47 physically fit, and will it work, or should I get the stuffed kk87 re-skinned?

basically, any advice most gratefully received!!


Kindest regards,


ANdyP

Innetrube audio probably requires the 87/67 capsule, which both have an inbuilt HF rise... the 47 will not have the rise, and as such will very likely be MUCH duller-sounding.

Keith

dear Keith,


I forgot about that hf rise! Fanx.



Kindest regards,


ANdyP

Maybe disconnect the .47uf from the drain side? This removes the EQ. Grounding the cap side that was connect to the drain should help filter noise in the capsule supply.

The capsule supply is driven via the .47uf and note the 330K in the capsule supply

Should give you a nice flat amp for the 47 capsule

Or reverse the capsule sides if all you use is cardiod, sometimes this works.

Does the inner tube kit have EQ in the amp or is it a simple plate out cathode biased flat tube triode stage?

Dear Gus,

very interesting! I was just about to ask if someone could show me the eq network to counteract this famous hf rise! Now I understand where it is in the u87, but can someone show me where it is on the u67 and/or m269 circuit diagrams? Can't seem to work it out . . . .


Many thanks,



ANdyP

Hi,

looking further, Is it perhaps c17 on both u67 and m269? feeding back hf from output of transformer to input?


????


ANdyP

Someone posted a link about the u67 at Klaus's sometime ago. IIRC the link was also posted in a Waveborne 770 microphone thread here.

http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=US3207848&F=0&QPN=US3207848

Found this link in a thread at Klaus's