Neumann U67 Clone : D-U67 Tube Microphone Build Thread.

[Khron]

There are some mentions in this thread about bridging pin1 from the 3-pin XLR and pin3 from the 7-pin XLR. I have not done this as for now, would this get rid of the hiss?

That's more likely to affect low-frequency hum or buzz (dealing with 50/60Hz mains interference and/or harmonics thereof), rather than hiss.

Hiss usually points to higher-frequency noise, more often originating in leakage-causing/conducting subtances in the high-impedance areas of the circuit. Which is not unexpected (perhaps even likely) in this dog's breakfast of a physical design

Easiest thing first - try some other tube(s). If the noise stays the same, that points to the thing(s) that stay the same, ie. the circuit and/or construction.

 

[happyforreal]

So i put in a different tube. Still same story. very low output and very thin sounding.

I am pretty sure that the circuit is alright. Are there any other measurements beside H and B that could bring me further?

 

[Khron]

Are you 10000000000% CERTAIN you got ALL the transformer wires connected to the correct spots?

 

[happyforreal]

i used the wiring diagramm from mobie's website
https://www.mobytransformers.com/_files/ugd/692932_1ddc04d43b7841aab6ebc92bf7d4b662.pdf

The only thing that irritated me was that at connection 7, there need to go the two black wires as well as pin 7 from the 7-pin xlr. is that correct?

 

[happyforreal]

Any ideas?

 

[youngshu]

I finally got mine working and it sounds amazing with the BeesKneez capsule! Any one have any advice on what Caps I can change to mess with bass response and de emphasis? want to try some different things for more or less high end and bass.

 

[Whoops]

Any one have any advice on what Caps I can change to mess with bass response ?

You can remove the connection in S2, just open S2 and you will have more bass and more bass extension, you will also have more bass in proximity effect, so it's something to consider.
I prefer to have mine with S2 open, and use Pop-shields and distance when I feel that too much bass is a problem.

S2 it's a low cut inside the circuit, leaving it close or open it's an user decision

Any one have any advice on what Caps I can change to mess with de emphasis? want to try some different things for more or less high end

Some people remove C17 for less Hi-Freq attenuation, but the overall circuit is not that simple, and the De-Emphasis network is a bit complicate, personally I would not mess around with it.

This has been discussed a lot in this forum in the past, you should read this:

https://groupdiy.com/threads/u67-de-emphasis-network.68495/