Anybody would have few 2N4856, 2N4857 or 2N4858, and few 1 G ohm resistors ?

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Hello

I have myself few Brüel & Kjaer 4145 mics capsules, unpolarised capacitor mic that needed a 200V polarisation voltage, but I don't have a power supply/preamps.

So I will use this HP15118A mic preamp schematics as a preamp and a 200v voltage regulator.

condensermicpreampHP15118Amicpreamp - HostingPics.net - Hébergement d'images gratuit

Q1 1855-0020 = SFE793--2N4856 or 2N4857
Q2 1854-0307 = BCY 57/LV2345---bc109, 2n930
CR1 51.1V 5% Zener
CR2 1901-0376 = 1N3595 ----35V working 2 pF at 0V low leakage.


Thank

Bye

Gaetan
 
Hello

Here is the schematic for the preamp and power supply for the B K 4145

Bye

Gaetan
 

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