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

[Purplenoise]

Awesome ! Let us know about the shootout and don't be shy to post audio examples !

Sure thing, I’ll do some samples later on once the mic is burned in and match the response to the original. I have a few different values for c17. So far I’ve compared it to a vintage 70’s U87 since these mics are “cousins” and the response is pretty similar. The u67 sounds less dry than the 87 if that makes sense with sweeter presence.

 

[Purplenoise]

Ok a little update. Shot it out briefly with a reissue Neumann 67 and....they sound almost identical...to the point of doing punch ins and not realizing it’s a different mic. The original was a touch thicker in the low mids so I swap tubes and....that was it. With the same tube the difference is even smaller...well within the difference between two Neumann u67’s. Really excited about this....this is the real deal. Even the output gain is almost identical

 

[poctop]

Ok a little update. Shot it out briefly with a reissue Neumann 67 and....they sound almost identical...to the point of doing punch ins and not realizing it’s a different mic. The original was a touch thicker in the low mids so I swap tubes and....that was it. With the same tube the difference is even smaller...well within the difference between two Neumann u67’s. Really excited about this....this is the real deal. Even the output gain is almost identical

Cool ,  I am glad this circuit works with the right Parts ,  now i want make myself one  ;D.
id love to see a couple of Pics,
Best,
Dan,

 

[Purplenoise]

Cool ,  I am glad this circuit works with the right Parts ,  now i want make myself one  ;D.
id love to see a couple of Pics,
Best,
Dan,

Haha...here are a couple of pics with the power supply still not finished and the test tube in

 

[Purplenoise]

Cool ,  I am glad this circuit works with the right Parts ,  now i want make myself one  ;D.
id love to see a couple of Pics,
Best,
Dan,

And the other pic

 

[poctop]

now i miss this like Button  ,
Best,
Dan,

 

[Purplenoise]

now i miss this like Button  ,
Best,
Dan,

Haha...thanks. I have built a D87 and now  this D67. Although a complete newbie with the help of the members of this forum they came out absolutely amazing....they are right up there with the originals, and in the process I’ve learned quite a few things. Again thanks to all and kudos for an amazing kit and all efforts that went into it. The whole experience is priceless.

 

[xarolium]

Nice job

About my build, i still notify a background noise like "fire bubble". I let my tube burn like 2 days that improve a little bit the S/N ratio.
I cleaned all flux but noise still there.
Here is some pics of my build maybe i done something wrong.
Thx for your help

 

[Purplenoise]

Nice job

About my build, i still notify a background noise like "fire bubble". I let my tube burn like 2 days that improve a little bit the S/N ratio.
I cleaned all flux but noise still there.
Here is some pics of my build maybe i done something wrong.
Thx for your help

I don’t know if that helps but when I first finished my build I had a little noise...very little but it was there. After I rearranged the wires at the high impedance area over the tube so that no wire touches any bare lead and also putting some tape over a solder joint at the back of the pcb that was contacting the body’s frame rail the noise disappeared completely.

 

[xarolium]

I don’t know if that helps but when I first finished my build I had a little noise...very little but it was there. After I rearranged the wires at the high impedance area over the tube so that no wire touches any bare lead and also putting some tape over a solder joint at the back of the pcb that was contacting the body’s frame rail the noise disappeared completely.

Thank you for the trick i will try it as soon as i can

 

[FarisElek]

Starting my build soon and currently getting the materials together. Has anyone tried the Beesneez BV 12? I have good report with them and trust their quality but I was interested if anyone had any experience with their transformers as that seems to be one of the main kickers on these builds.

Ryan

 

[Purplenoise]

Hey guys. A couple of questions.
I am building a second 67 this time with almost the same parts as the reissue. ( k870, haufe bv12, exact Vishay 1839  caps etc) In our reissue the coupling cap is an electrolytic 1uf 350v. I can’t see the manufacturer’s label...anybody knows? I have same specs nichicon and Illinois. This should be an interesting comparison between u67 and d67.
Has anybody tried a PIO cap for the coupling cap? I am expecting a couple of Russian ( k42 I believe) 1uf and .47uf 250v. Thanks.

 

[Delta Sigma]

I used a Russian metalized paper output cap and preferred it over the film caps from the BOM.

 

[Purplenoise]

I used a Russian metalized paper output cap and preferred it over the film caps from the BOM.

Thanks, what did you hear? What was the difference?

 

[Delta Sigma]

Thanks, what did you hear? What was the difference?

Hmmm... that's tough. It's all very subjective. The film cap sounded cleaner, maybe a little stiffer or plastic sounding. The MP sounded a little more distorted or warm. You'll really have to give both a try. Keep searching Ebay, there can be some decently priced batches of Russian PIO and MP caps on there. Some MP sold as PIO too so watch out, try and see if you can read the actual cap in the photo.

Edit: difference was very small. Changing the output cap won't make or break a build.

 

[Purplenoise]

Hmmm... that's tough. It's all very subjective. The film cap sounded cleaner, maybe a little stiffer or plastic sounding. The MP sounded a little more distorted or warm. You'll really have to give both a try. Keep searching Ebay, there can be some decently priced batches of Russian PIO and MP caps on there. Some MP sold as PIO too so watch out, try and see if you can read the actual cap in the photo.

Thanks, that’s my findings too about film caps. I hear it more on the high end that sounds more papery...not bad at all and in the mix it sounds defined and upfront. PIO’s to me feel that are placing the sound a little “further behind”...a little smoother overall with more natural high mids and highs. Both sounds have their uses...subjective as you said.
I am waiting for some green k42 and silver k75 from Russia. Thank you so much for your input.

 

[xarolium]

I don’t know if that helps but when I first finished my build I had a little noise...very little but it was there. After I rearranged the wires at the high impedance area over the tube so that no wire touches any bare lead and also putting some tape over a solder joint at the back of the pcb that was contacting the body’s frame rail the noise disappeared completely.

I rearrange wires of capsule and switch board, make it shorter and now my D67 is dead silence 
Thank you very much for your help

 

[Purplenoise]

I rearrange wires of capsule and switch board, make it shorter and now my D67 is dead silence 
Thank you very much for your help

That’s awesome , I am really glad it worked out.

 

[FarisElek]

It appears that I did not receive a on/off switch for my PSU in the BOM. Is there a recommended part?

Ryan

 

[Purplenoise]

It appears that I did not receive a on/off switch for my PSU in the BOM. Is there a recommended part?

Ryan

I used something like this one. It works great.
https://www.amazon.com/Gardner-Bender-GSW-18-Heavy-Duty-Electrical/dp/B00004WLKC