KM84 circuit experimenting in progress ...

[gary o]

Great info about the other Mic models  im going to try maxed bv08 transformer in km84 circuit think it's about 7:1 I believe.

 

[gary o]

Having fun with this circuit added feedback/no feedback switch tried larger C3 & C1..... have been reading U87 build thread reading about the lower output level of U87, Im not finding this circuit to be too low output its not far off my DIY tube mics & Oktava mics I have

 

[gary o]

Thinking of adding a PP3 9 volt battery to the circuit to boost the polar voltage if I cut the junction of R1 & R8 & wire the battery in series that should work right ? maybe add 12 or 15 volts ....

 

[gary o]

I want to try a K67 capsule and so add a demphasis circuit been looking at the U87 schematics I need a little help

http://www.google.co.uk/imgres?imgurl=http://recordinghacks.com/images/mic_extras/neumann/U87-schematic.png&imgrefurl=http://recordinghacks.com/microphones/Neumann/U-87&h=1118&w=1600&sz=96&tbnid=Po5JMr3gPFT3CM:&tbnh=90&tbnw=129&zoom=1&usg=__t1FYbTKS-sGgBzQ3F0NHsy_Spwc=&docid=oElt8AEf2vkXXM&sa=X&ei=Pyt9Upa6DpSAhAfLjoCIDg&sqi=2&ved=0CDAQ9QEwAA

Im guessing I need to add U87s C9 .47u C6 220p & R8 1Meg I guess from the KM84s Drain as in U87 schematic but not sure where to frrd back in ..... at capsule back plate ?

Thanks