Transformerless Neumann SDC Help?

[gabasa]

Hi Everyone,

I haven't been here in a while, but I'm happy to be taking on another mic project! I have some mic pcbs with a Neumann KM84 on them that I want to populate. However, I'm toying with the idea of making them transformerless, with a capacitor output. My cleanest, clearest sounding mics are my AKG C460B's, with Jim Williams mods that I implemented a few years back, so I want to work with a transformerless concept using these boards.

Attached is the Neumann KM84 schematic. How difficult would it be to modify the circuit to a capacitor-output design? It can't be that difficult, can it? It's only four connections.

Cheers, and thanks in advance for the help.

 

[Khron]

Not impossible, but you DO need at least one transistor as an emitter follower of some sort, that can drive the low impedance of the cable + preamp input. That will, of course, require some extra current, so if your capsule is biased straight from the phantom feed, that will reduce the available voltage.

 

[kingkorg]

Or maybe go for this one, i tested it, extremely clean, high headroom, and very simple.

http://russelltechnologies.co.uk/images/rt-schoctava.sch.pdf

The hole story:

http://russelltechnologies.co.uk/rt-012.html

 

[doqmemory]

Or maybe go for this one, i tested it, extremely clean, high headroom, and very simple.

http://russelltechnologies.co.uk/images/rt-schoctava.sch.pdf

The hole story:

http://russelltechnologies.co.uk/rt-012.html

Schoctova can sound great with a decent capsule.

 

[gabasa]

Thanks. I can probably chop a breadboard to the exact dimensions I need and take it from there. Robert from Russell Technologies is awesome.
The Neumann KM100 mic does seem to have what I'm after, but I can't find a schematic anywhere.

 

[Voyager10]

Also worth considering: https://groupdiy.com/threads/a-very-versatile-input-stage-for-sdc-mics.80172/ from @MicUlli . Low parts count and good noise performance.