U47 FET pcb.

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Igor

Well-known member
Joined
Jul 17, 2006
Messages
2,193
Location
Israel
Have a Skylar body. Well, not his, but the mic one.

Now, working on this:

u47fetpcb.jpg


I want to add polarity patterns like in U87 etc.

Any recommendations for good step-up schemo for 60V polarization for capsule?
 
Beat me to it :) I'd already started something similar, but for the 87ish style bodies that are being used for the U1621. Neumann actually made a microphone that was a fet47 circuit in a u87 style body, but I can't find the model number anywhere to bring up a picture.

Oliver at TAB has a transformer spec'd for it that I'd love to check out.

I hadn't gotten as far as stepping up the voltage yet, so I can't be much help on that front. I can't wait to see some suggestions.

EDIT: Found it. The Neumann U497, built in limited numbers for french broadcasting. It was a K47 capsule with U89 style multi-pattern fet electronics built in to a U67/87 style body. I'll start digging for schematic, though I think it's prob a long shot.
 
Looking great mate  ;) as usual. Btw, do you have idea about output transformer?  Be aware of "modern" type of lamination since vintage lams alloy doesn't exist anymore. At least for BV8 ;)
 
The Neumann U497 was made for French broadcast organisation and used a uncommon 12V power supply... Keep that in mind if you want to modify its circuit for your purpose.

Or you can have a go at the U87A/U89 circuit.

Axel
 
really interesting project Igor... once again!!! What capsule will suit this project? and will you maybe post a circuit? :)
 
Marcocet said:
Anybody have any info on the transformer? I know Tab-Funkenwerk makes an exact copy but they're custom order and expensive.
I'm not sure about winding/ratio but it looks that lams are same as BV8. Also, it looks that shares the same but not 4 chamber bobbin. If that's true I'm sure it's not a big deal (except obsolete lamination alloy/shape). I would like to know about it too since I'm done with BV8  ;)
 
Igor, did you find the DC step up solution? I never tried this circuit but maybe it's worth of trying  :eek:

http://www.instructables.com/id/Simplest-Ever-DC-DC-Boost-12v-to-73v/step3/Connecting-the-power-transistor/
 
Bump to see how this is progressing, Igor.  I'm really interested in a pair of these...
 
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