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Isn't the cascode an inverter?

The schematic is in error. XLR1 Pin 3 goes to XLR 2 Pin 2. XLR1 Pin 2 goes to XLR 2 Pin 3. This implies that we get a polarity shift. Very bad design indeed. Is this really the original schematic or a

Hi Jerry, You're right, the second one is the simplest48 circuit.

Bob, I have bought some very old and dirty microphones at flea markets or recycling stores. I am not a professional micbuilder, but I am always happy when I can find technical information about the

Heinz, I looked again at the RCA handmic link you sent & think I found the schematic for mine. It shows an unidentified PNP along with the resistors & cap that is on my mic's board. Thank you

Thanx Heinz. Never thought of searching for a pdf. Duckduckgo didn’t find that. I did more surgery on it & in the base there is a small amplifier in it. It has a RCA branded 2N408 germanium PNP

Hi Bob When I searched Google for: "MI-559156" filetype:pdf Two results came up: Shure OEM Model Prefixes https://content-files.shure.com ?

I've attached the Primo EM272 datasheet.? Look at the diagram on the right, that's what I'm referring to.? In the place of the 5 volt battery you can use a 9 volt battery and a higher value

Greetings, I've a RCA/Shure Model # MI-559156 that I am trying to find a schematic or user manual for. This mic looks like a 444 or 444D & has a Shure Brothers sticker on the bottom but has some

Yes, connect the metal strainer to pin 1 of one of the XLR connections. It's easy to test if you can borrow a metal strainer from your kitchen. A test lead with alligator clips is useful here.

Id like to try the metal strainer approach. Where do I ground this to tho? Would I use a ground of one of the xlr connectors?

I cant imagine this being the case. As I said in the other thread, apart from the electrical buzz they sound fine. But I think the capsules are different because there wouldve been at least some other

This is different than the schemo in your previous post. The former has a capacitor to isolate DC, the latter has none. Both may work but require different values for the resistors.

Another picture for assembled components.

This is the snapshot from the original video.

We read about your buzz/hum issue, and threw out some solutions for that. Beside that issue, did your 2590 lookalikes work at all? They usually do, even though their specs aren't quite the same. Be

Hey Scott, Pls allow me some beginners questions. Is what you are describing similar to the simple P48 circuit just with a smaller resistor? And would 4,7 uF be a "nice big" capacitor? And the 9V is

There is conduction between drain and source in a properly biased FET. From pin2, current flows through Q3, then Q4, then R6 and R7, back to pin1. >

So this setup could be built actually fairly simply - no need to have phantom power or anything like that. Too complicated. Going back to the kind of electret capsules that kick-started the mic DIY

S1 & S2 is understandable, but the power issue still escapes me. The only point at which V+ power can reach the circuit is from XLR2. But I don't see how power gets distributed. If V+ is present on