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

[poctop]

Did a shootout  between the 67 and one half of my sm2 tonight. The competition was fierce! Both great tools, the sm2 was smokey and the 67 was much more articulate, more air. Just what I wanted! But they were out of phase. Have to find out which one now. I'll put the 67 up against a bunch more mics tomorrow - majority rules.
I found that a 47k resistor on the series plate pot put the pot in a more useful position, but it might just be my tube.
Dan, there are two post sets labeled LC and IS, LC is a switch hookup. Does IS represent S2 on the Neumann schematic? Should IS be open or closed.
Keep up the good work, this is a great project,
Pete

Thanks Pete Glad this is coming along
Question 1) What is a half of a SM2 ?  i am not sure i know which mic it is Let me know ,

And the LC is indeed the Low Cut Switch hookup and the IS = internal switch S2 you are correct ,
i think it linerarise when out, the low cut region for broadcast app , according to the schemo it is close by defautls, know i have tried it in the validation and it works,  here is the comments from the U67 manual regarding this,  So Basically if you need less bass and steeper low cut behavior make sure you have the jumper in , if not leave it open ,
Let me know if it helps,
Best,
Dan,

 

[poctop]

Here is the Doc in question,
Best,
Dan,

 

[dandeurloo]

Dan, I take it the 560R in the BOM is for R9 (536r) on the PSU.

 

[poctop]

Dan, I take it the 560R in the BOM is for R9 (536r) on the PSU.

Correct,
Best,
Dan,

 

[micaddict]

So Basically if you need less bass and steeper low cut behavior make sure you have the jumper in , if not leave it open

This, along with de-emphasis of the pre-emphasized capsule, separate feedback winding etc., is one of those things that make a U67 what it is. After the U47, there was demand for a studio LDC with less proximity and less popping. The built-in 40Hz low cut (not to be confused with the 200Hz low cut switch on the body), among other things, makes it a singer's microphone. Without the jumper, it will be more suited for orchestral work, or recording a large pipe organ for instance, but it will be less what a U67 is typically known for IMO. And for the other purposes, many would likely pick a couple of omni Schoeps or something of the sort, anyway.
But yes, it's nice to have the option. 

 

[ktfstudio]

Thanks guys, that's what I thought.
The SM2 is an early Neumann stereo sdc tube mic.

 

[Volume11]

What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

 

[poctop]

What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

Use the 56r in the mic bom this resistor is in the calibratio line so it will not have any impact on the sound more like the reference preamp data checks
It should be in the BOM
Hope this helps
Dan

 

[Volume11]

What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

Use the 56r in the mic bom this resistor is in the calibratio line so it will not have any impact on the sound more like the reference preamp data checks
It should be in the BOM
Hope this helps
Dan

Ok, thanks again Dany

 

[poctop]

Any Build  O uthere  :-X ?

 

[ktfstudio]

This has been a gripping thread the last couple of days hasn't it?
I'll contribute; I have found that my du67 is out of phase with the rest of my mics but I haven't spent any time to try to figure it out other than recheck the xlr.  Just mentioning so everybody checks.
To anybody that thinks they will save some time and use the swithc PCB that came with the case - don't. That grounding on Dan's PCB is needed. It's easy enoung to jump one in but it's not as clean.
I've ordered some telefunkens from Germany, Mouser is sending me another Triad, (first one was bad) so in a week or two I'll have my pair. Tomorrow night marks the first session with the first one and I'm excited to hear it in the mix. From all the testing I've done so far the thing that stands out the most in the mic is the sound stage clarity. It seem to have more than it's mono send.
After the session I might decide to increase the feedback or pull the switch 2 jumper. I love that there is so much you can do to tune this mic.
Hope all the builds are going well,
Pete

 

[kpearsall]

My build is going great, just on hold waiting for capsule and transformer to show up. All wire used is silver teflon, AC input and trimmers wired with cloth covered silver teflon because it looks cool, and was nice and thick  ;D

Mic PCB itself was quite fun to build! I'm even a little proud of how neat I was able to keep it following Dany's pictures. Looking forward to building the second one, but next time I'll be ording the cap and transformer FIRST! haha

 

[ktfstudio]

Can I ask what cap you selected?
I don't know what silver teflon is but it sounds cool.

 

[kpearsall]

I'm getting the BeezNeez capsules for my 67's. They haven't shipped yet but I know they will be worth the wait.

The wire I'm speaking of, is silver coated copper wire, with a teflon insulation. Expensive, but if you only need a few feet of it, why use the cheap stuff?

 

[poctop]

This has been a gripping thread the last couple of days hasn't it?
I'll contribute; I have found that my du67 is out of phase with the rest of my mics but I haven't spent any time to try to figure it out other than recheck the xlr.  Just mentioning so everybody checks.
To anybody that thinks they will save some time and use the swithc PCB that came with the case - don't. That grounding on Dan's PCB is needed. It's easy enoung to jump one in but it's not as clean.
I've ordered some telefunkens from Germany, Mouser is sending me another Triad, (first one was bad) so in a week or two I'll have my pair. Tomorrow night marks the first session with the first one and I'm excited to hear it in the mix. From all the testing I've done so far the thing that stands out the most in the mic is the sound stage clarity. It seem to have more than it's mono send.
After the session I might decide to increase the feedback or pull the switch 2 jumper. I love that there is so much you can do to tune this mic.
Hope all the builds are going well,
Pete

Thanks Guys For all your inputs,  can't wait to see more and hear more about ya  ;D

Regarding the out of phase thingy ,  must be a simple thing ,
the only confusing part but you probably check that already is that the german pin 2 is our pin 2 and the german pin 1 is our pin 3 and the german pin 3 is our pin 1 ,
check the Schemo of the power supply it actually show the inversion already made and mic togheter and trace those to the Transfo to make sure it is in the right order, the tuchel and cannon are not the same and depending on number and times also the hot and cold differs also,
Keep us posted,

thanks Again Guys,
Dan., 

 

[poctop]

What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

how many 60M had you , there is 3 used in the mic , R2, R9, R16,
also In the PSU  there is one of 56R For R20 Best,
Cheers,
Dan,

 

[ktfstudio]

Thanks Guys For all your inputs,  can't wait to see more and hear more about ya 

Regarding the out of phase thingy ,  must be a simple thing ,
the only confusing part but you probably check that already is that the german pin 2 is our pin 2 and the german pin 1 is our pin 3 and the german pin 3 is our pin 1 ,
check the Schemo of the power supply it actually show the inversion already made and mic togheter and trace those to the Transfo to make sure it is in the right order, the tuchel and cannon are not the same and depending on number and times also the hot and cold differs also,
Keep us posted,

thanks Again Guys,
Dan., 

Thanks for this Dan,
Check it out! I didn't know that! As soon as my reading mind comes back I'll look into it.

 

[poctop]

Merged info tht was on wM ,
Thanks,

 

[Volume11]

What value did you guys use for r20? I didn't have a 60 ohm in my mouser order and I don't see one in the bom. I did have an extra 60m though. Maybe a mistake in the bom? Anyone have a part number? I did a quick search and it turned up a bunch of values around 60r, nothing spot on though.

how many 60M had you , there is 3 used in the mic , R2, R9, R16,
also In the PSU  there is one of 56R For R20 Best,
Cheers,
Dan,

Just noticed this question. I will check first thing tomorrow and post back.

I am surprised that no one has posted any build pics yet. I found a local powder coating company that quoted me $15-40 for two mikes, depending on the colors I choose. I'll post some pics as soon as I get them done. Hopefully by then the capsules will arrive. I'm thinking of maybe getting the head baskets and retainer rings chromed as well.

 

[poctop]

I am surprised that no one has posted any build pics yet.

+1