Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread

[mgronroos]

Hi Guys!

Just chiming in to report another D-U47FET-build in progress! 

This is yet another well designed set of PCBs from poctop, so the build is very fun and straight forward.
I opted for the R2 and bias bridge combination to make things easy..

The plan is to use the GT-2B donor body from Chunger when they arrive.
I am thinking of using the Cinemag 13101 transformer as I have read good things about it, and it seems designed specifically for the U47FET.

Anyone here who has tried the T49 and wants to add something about it in U47FET applications?
The price is virtually the same, though I have not read som much regarding the T49 and I don't know if it is specifically made for the U47FET.
Feel free to let me know your thoughts! 

Best,
Michael

 

[Nyquist]

Hi guys. I finished my build. I used the RK47 capsule, Styrene caps and Cinemag 13101. In the first test it sounded really thin and the sibilance was terrible. So I went through my work and everything seemed to be correct. I decided to change out the 20pF styrene cap (supplied by Danny) with a 10pF Mica Mouser #598-cd15cd100d03f. The difference was night and day. The Mid'ss Mid/Hi's and Hi's all fell into place. I guess it is possible that the styrene was faulty but, I could not test it as I don't have a capacitance meter. I did wonder if the RK47 was brighter than the original capsule when I ordered it as the RK47 only has a 3 microns rather than the original K47 being 6 microns.

I also noticed this mics has a fair whack more output than my 87 clone. Has anyone else noticed this?

 

[poctop]

Hi guys. I finished my build. I used the RK47 capsule, Styrene caps and Cinemag 13101. In the first test it sounded really thin and the sibilance was terrible. So I went through my work and everything seemed to be correct. I decided to change out the 20pF styrene cap (supplied by Danny) with a 10pF Mica Mouser #598-cd15cd100d03f. The difference was night and day. The Mid'ss Mid/Hi's and Hi's all fell into place. I guess it is possible that the styrene was faulty but, I could not test it as I don't have a capacitance meter. I did wonder if the RK47 was brighter than the original capsule when I ordered it as the RK47 only has a 3 microns rather than the original K47 being 6 microns.

I also noticed this mics has a fair whack more output than my 87 clone. Has anyone else noticed this?

Polystyrene caps can go bad really quick if overheated special care with those,
as far as the gain goes , it should not be really really more hotter than the U87i, if the impedance is not correct it will have more gain and pretty bright ,
I would defo check the transformer wiring to make sure you did not put it in reverse , have seen it before, 
this will make it bad,

 

[Nyquist]

Cool thanks mate. I'll check over the wiring of the trans.

 

[Nyquist]

Hmmm okay It checked through the wiring of the Trans and all is correct. Ohms reading are correct and the phaseing is correct. Any other reason why the mic sounds thin with hot gain? 

 

[poctop]

Hmmm okay It checked through the wiring of the Trans and all is correct. Ohms reading are correct and the phaseing is correct. Any other reason why the mic sounds thin with hot gain?

a transistor badly oriented or a build error,
Best,
DAn

 

[mgronroos]

Check the orientation on T4.
It is easy to assume it should be aligned as the others and overlook that it is actually turned the other way round.
I almost made myself unhappy with that one..

Good luck and let us know your progress!

Cheers,
Michael

 

[Nyquist]

I have checked all components. Transistors are in the correct orientation, Caps are correct value components and in the correct orientation. Resistors are correct values (I measure each before stuffing). Have checked my work over and over. This is not my first DIY. IT's maybe the 30th.

My suspicions are the RK-47 I have is a piece of shit.
In any case I'll just chuck it in the cupboard and use my D87 instead. It has come up fantastic.  Thanks

 

[kante1603]

My suspicions are the RK-47 I have is a piece of sh*t.

That's what I thought.....

Udo.

 

[kidvybes]

...I also find the 3-micron RK-47 rather bright...the microphone-parts RK-7 is not quite so bright and uses 6-micron mylar...

...but here's the interesting thing I found...the 35mm center-terminated capsule that Chunger sells as his "K67" for $32 bears more than a coincidental similarity to the Peluso CEK-47, below (same metalwork, 6-micron mylar and even the wiring is the identical colors)...if I remember correctly Chunger put it in one of his 47-style builds, then he lent it to a studio for testing, and they expressed a desire to keep it...that 35mm K67 does not display the typical high-end bump associated with classic K67 and K87 capsules...as a matter of fact, Dave Thomas uses that same capsule as the stock option on his CM-47 tube mic...

...just thought I'd put that out there...

 

[Matador]

...I also find the 3-micron RK-47 rather bright...the microphone-parts RK-7 is not quite so bright and uses 6-micron mylar...

...but here's the interesting thing I found...the 35mm center-terminated capsule that Chunger sells as his "K67" for $32 bears more than a coincidental similarity to the Peluso CEK-47, below (same metalwork, 6-micron mylar and even the wiring is the identical colors)...if I remember correctly Chunger put it in one of his 47-style builds, then he lent it to a studio for testing, and they expressed a desire to keep it...that 35mm K67 does not display the typical high-end bump associated with classic K67 and K87 capsules...as a matter of fact, Dave Thomas uses that same capsule as the stock option on his CM-47 tube mic...

...just thought I'd put that out there...

Recordinghacks.com says that "The CEK-47 uses imported metalwork; diaphragms of German Mylar are fitted and tuned in the US."...do you think the brass-work is identical and simply the diaphragms are different?  Or are you thinking that Peluso is selling the Chinese K67 as-is?

 

[kidvybes]

Recordinghacks.com says that "The CEK-47 uses imported metalwork; diaphragms of German Mylar are fitted and tuned in the US."...do you think the brass-work is identical and simply the diaphragms are different?  Or are you thinking that Peluso is selling the Chinese K67 as-is?

...Dave Thomas has on more than one occasion stated that his K67 capsule is the result of John Peluso and Verner Ruvalds original designs as manufactured in China (same as Chunger's capsule)...Peluso/Ruvalds article linked below...

...I can't comment on what Peluso actually does in terms of skinning, but the metalwork/screwheads are clearly the same as well as the wire colors and connections...the subject about skinning came into question when it was noted that the capsules had red lock-tight on all of the wire terminations (as they are shipped from China) and grey lock-tight on the backplate screws (see pic below)...why 2 colors of lock-tight?...was Peluso simply adding the grey lock-tight after manufacturing?...when you consider the distribution of Peluso products worldwide, could he be skinning all of these capsules on his workbench himself?...draw your own conclusions...

http://www.npr.org/templates/story/story.php?storyId=89705610

 

[Matador]

Yup, makes sense.

I'm curious why people are running away from talking about "Chinese brasswork" in their products:  the pieces I have seen in samples coming from China are really top-notch and of remarkable quality (especially for the price)...

Nothing to be ashamed of in my opinion!

 

[Nyquist]

Yeah I suspected it was the capsule. I might buy chungers 67 cap and give it a whirl.  I'll be back with my findings.

 

[Andydrum82]

Hey guys this is my first post & first time building a DIY mircophone. So I have populated the PCB's & have wired in the XLR connector. I am nervous about wiring the capsule to the board as it has 2 wires for the backplate & 1 on the side. Where do these go? Do they connector to one of the molex pins? Also the Gound hole near the XLR holes is that for the transformer ? I am using the Cinemag 13101. 

 

[wave]

Hey guys this is my first post & first time building a DIY mircophone. So I have populated the PCB's & have wired in the XLR connector. I am nervous about wiring the capsule to the board as it has 2 wires for the backplate & 1 on the side. Where do these go? Do they connector to one of the molex pins? Also the Gound hole near the XLR holes is that for the transformer ? I am using the Cinemag 13101.

Have you looked through the build up pics that Dany posted in the 1st page of this thread?

-Dave

 

[Andydrum82]

All sorted out now. Just a dumb moment on my behalf

 

[Nyquist]

Hi Guys, Finally I got my hands on another capsule. It was supposed to be for my M49B build, but it ain't coming out of this mic in a hurry. I'll have to order another.

Sound files between the RK47 capsule and Cathedral Pipes (Dale) M7.
No processing apart from gain matching.
No creamy pre just recorded through an A&H QU24 console into Cubase 7

Love the Dale M7! So smooth

Also the test confirms my thoughts, the RK-47 (well the one I bought anyway) is junk.



RK-47
https://www.dropbox.com/l/Lqt3IhDnIgmfLLQ3K2NAAq?

M7
https://www.dropbox.com/l/AQWyj6DptojEDj53JKAoZn?

 

[EvLoutonian]

Sound files between the RK47 capsule and Cathedral Pipes (Dale) M7.

Wow - They're SO different!

I also have the Cathedral Pipes "Dale M7" capsule in my MK47 (PCB) mic, and it sounds pretty fine there, too!
I kind of recognise the "weight" that I hear in your recording from that capsule, I guess.

It partly makes me curious to try something more akin to a traditional K47 capsule in my MK47 mic at some stage, to hear the difference, and it also makes me feel like I should get of my butt and complete my 2x D-U47fet PCB's some time!

Thanks for sharing.
Evan

 

[poctop]

Hi Guys, Finally I got my hands on another capsule. It was supposed to be for my M49B build, but it ain't coming out of this mic in a hurry. I'll have to order another.

Sound files between the RK47 capsule and Cathedral Pipes (Dale) M7.
No processing apart from gain matching.
No creamy pre just recorded through an A&H QU24 console into Cubase 7

Love the Dale M7! So smooth

Also the test confirms my thoughts, the RK-47 (well the one I bought anyway) is junk.



RK-47
https://www.dropbox.com/l/Lqt3IhDnIgmfLLQ3K2NAAq?

M7
https://cdn.groupbuilder.com/groupdiy/u/39511/58d02819942af?

Thanks For taking the time to record these samples,
I Love the accent as well, we dont have those arround here
always appreciated,
Best,
Dan,