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

[FarisElek]

No heater voltage and blowing fuses.

Is the 20v transformer wiring supposed to be on pad 2 and 3 or 1 and 4?

 

[TillM]

did you check the wiring diagram from the psu ?
http://www.vintagemicrophonepcbkit.com/D67B/D67B/U67%20PSU.pdf

 

[FarisElek]

did you check the wiring diagram from the psu ?
http://www.vintagemicrophonepcbkit.com/D67B/D67B/U67%20PSU.pdf

Yeah, that’s the one.

I’m using the 186B20 transformer.
I followed the diagram and it wasn’t working.. I found someone else  in the forum that drew it out and I think maybe this might work. They shorted 1+3 and 2+4 on the 20v transformer. And have everything written on that diagram going to 1 and 4 instead of 2-3 as show (or appears to show). Once I get new fuses I’ll try it out.
I’m

Edit: I used a homemade current limiter from a lightbulb and the new wiring seemed to work. I only got 10.5v on AC20, but that might be from the current limiter. Much better than the previous .5v. We will see when I get the fuses.
If anyone thinks something other than the 186b20 writing caused my fuses to blow, I’m all ears.

 

[TillM]

Are you living in Europe ?
Than you must connect 2 and 3 together.
One cable to 1 the other to 4.
The primary side must be in series to get 230v.

 

[FarisElek]

Are you living in Europe ?
Than you must connect 2 and 3 together.
One cable to 1 the other to 4.
The primary side must be in series to get 230v.

I’m in USA

 

[Purplenoise]

Yeah, that’s the one.

I’m using the 186B20 transformer.
I followed the diagram and it wasn’t working.. I found someone else  in the forum that drew it out and I think maybe this might work. They shorted 1+3 and 2+4 on the 20v transformer. And have everything written on that diagram going to 1 and 4 instead of 2-3 as show (or appears to show). Once I get new fuses I’ll try it out.
I’m

Edit: I used a homemade current limiter from a lightbulb and the new wiring seemed to work. I only got 10.5v on AC20, but that might be from the current limiter. Much better than the previous .5v. We will see when I get the fuses.
If anyone thinks something other than the 186b20 writing caused my fuses to blow, I’m all ears.

That’s correct. 1 and 3 together and 2 and 4 together. Then from 1 and 4 to pcb ( or 2 and 3 to pcb since they are jumped)

 

[FarisElek]

Awesome, thank you! I wired it that way and now I’m just awaiting some replacement fuses to see if it worked. I started the Main PCB Of the mic today. I’m very excited and trying to go slow and be precise.

 

[Purplenoise]

Awesome, thank you! I wired it that way and now I’m just awaiting some replacement fuses to see if it worked. I started the Main PCB Of the mic today. I’m very excited and trying to go slow and be precise.

Didn’t you say you are in USA? TIIMs recommendation is for Europe I believe.

 

[FarisElek]

Didn’t you say you are in USA? TIIMs recommendation is for Europe I believe.

Yes, I meant to reply to you, purplenoise. I’m on my phone and accidentally quoted the wrong person.

 

[Purplenoise]

Yes, I meant to reply to you, purplenoise. I’m on my phone and accidentally quoted the wrong person.

Haha ok just makin sure.  Just make sure that everything else is properly wired though because you shouldn’t be blowing fuses even if you connected it the way you did.

 

[TillM]

Yes, I thought he is in Europe.
Please use the wiring from purplenoise, then it will work.
Secondary side is labeled 5 and 8 to pcb.

 

[FarisElek]

What is the 25ohm resistor for?

I used this -> https://www.mouser.com/ProductDetail/594-AC05W22R00J

and not this one -> https://www.mouser.com/ProductDetail/605-RWHSE09TU025R0FS

is that cool?

 

[TillM]

yes you can.

 

[Purplenoise]

Second d67 finished this time most components matching the reissue u67 ( k870, haufe bv12, 1839 Vishay, 1uf Electrolytic coupling cap etc). Kept the carbon film resistors. Works great. I think I might have gotten the “high tension” k870 cause it lacks a little low end compared to the reissue. I’ll let it burn in and change the tube to a Mullard soon.

 

[Delta Sigma]

Second d67 finished this time most components matching the reissue u67 ( k870, haufe bv12, 1839 Vishay, 1uf Electrolytic coupling cap etc). Kept the carbon film resistors. Works great. I think I might have gotten the “high tension” k870 cause it lacks a little low end compared to the reissue. I’ll let it burn in and change the tube to a Mullard soon.

Does your reissue have the fixed (40Hz?) high pass jumpered?

 

[Purplenoise]

Does your reissue have the fixed (40Hz?) high pass jumpered?

I believe so, they are new and “untouched”. The way they came from Neumann

 

[Purplenoise]

Does your reissue have the fixed (40Hz?) high pass jumpered?

After a few hours of burning it in the difference is even smaller...even with a different tube ( d67 has amperex, u67 tung sol). They are extremely close now...I guess the electronics need some time to “settle”

 

[FarisElek]

I finished my PSU I think, some of the voltages seem weird but I might be wrong.

AC in 210v
Top input: 270???
Bottom: 0

AC 20V In
top: 11.43
bottom: 10.82

H-:  -16.7DC

B+ : 227DC

 

[TillM]

Do you connect the mic ?
If not it’s pretty typical, cause your PSU is unloaded.

 

[FarisElek]

I did not connect the mic yet. That's great news! Thank you.