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

[poctop]

One has to wonder if all the interest in DIY classic mic clones was the inspiration for Neumann's (Sennheiser) latest decision to re-issue the 47fet...a friend at the AES show said that the Neumann rep said that based on the interest in this 47fet re-issue, they may decide on additional classic re-issues for the future...I suspect the DIY clone market was an, albeit small, but still a partof that decision making process at the Sennheiser headquarters...

http://www.u47fet.neumann.com/content/en/index.html

I guess only the Price of this mic is not vintage ......  ,
Best,
dAN

 

[kidvybes]

I guess only the Price of this mic is not vintage ......  ,
Best,
dAN

...that's true, but to some, the difference in cost is qualified by the "badge"...
...certainly not me!

 

[micaddict]

It's a single pattern, transistor microphone is what it is.
The price is madness.
But they own the goldmine name, so the market will bear it.
OK, perhaps they had to do some tooling to get things precise.
On the other hand, they may have had enough spare parts to do a hundred pieces (similar to the scenario when the U67 was reissued).

BTW, I think it's no coincidence they came with this reissue now. 


Henk

 

[RuudNL]

Someone recently asked my why the price of the Neumann microphones is so high?
I grabbed a U87 and pointed with my finger to the small square logo plate on the body.
"You see this?" I said, "This is a VERY expensive part of the microphone"...

(By the way: good to see you back Micaddict!)

 

[mappyo]

Hi all,

I have come close to finishing my FET47 build. I have a question about the capsule connections. My capsule has both a front and a back diaphragm. I see the markings for FD, front diaphragm, and BCK, backplate. I don't know what to do with the back diaphragm connection. Any suggestions?

Here is a picture  of my build so far. 

Thank you in advance for your help!

 

[poctop]

Hi all,

I have come close to finishing my FET47 build. I have a question about the capsule connections. My capsule has both a front and a back diaphragm. I see the markings for FD, front diaphragm, and BCK, backplate. I don't know what to do with the back diaphragm connection. Any suggestions?

Here is a picture  of my build so far. 

Thank you in advance for your help!

Very Nice build  ,  the back diaphrgame in this build is not connected just isolate the wire and leave it where it wont comes loose or create microphonics noise in the headbasket ,

Let Us know how this thing works out ,  i am jealous  ,

Best,
Dan,

 

[mappyo]

Hi all,

I have come close to finishing my FET47 build. I have a question about the capsule connections. My capsule has both a front and a back diaphragm. I see the markings for FD, front diaphragm, and BCK, backplate. I don't know what to do with the back diaphragm connection. Any suggestions?

Here is a picture  of my build so far. 

Thank you in advance for your help!

Very Nice build  ,  the back diaphrgame in this build is not connected just isolate the wire and leave it where it wont comes loose or create microphonics noise in the headbasket ,

Let Us know how this thing works out ,  i am jealous  ,

Best,
Dan,

Thank you!

 

[mgronroos]

Hey guys,

Yesterday the missing WIMAs came from Mouser so I could finish my second D-U47fet. Now we can make stereo recordings with them!

I finally went for the black powder coating with some structure. I left the headbasket as is though. Viery happy with the result, and love the sound!

Thanks again Poctop for this wonderful PCB!

Cheers,
Michael

 

[jrasia]

Hi, 

I have a couples questions before starting assembly of PCB 'B' of this build.  Particularly about the pad network.  I've read through the posts but still not %100 clear.
I'm using the cm3101 tranny, Styroflex caps, with Eric's hk47 on its way.  I'm trying to stay as truthful to the original u47FET as possible.

With that;

1.  What do the resistors options (33M vs 2x68m) translate to in terms db padding level.  If that's indeed what these resistors options are used for?  Does one offer more padding level than the other, or are they simply what was in stock and available through the BOM?

2.  Further, can someone also clarify the jumper settings for s1a, s1b so I know how to properly engage the pad?  I don't believe I'll be using a switch, but rather simply using jumpers on the pcb.  If I understand correctly, no jumpers, or jumpers in the same position on s1a, and s1b is the equivalent as NO PAD, but what is the correct jumping setting to engage it?  Does it matter exactly which pins and as which position?

Apologies, for the rookie questions.  I'm sure there will be more

Thanks

 

[Andydrum82]

I just fitted a Beesneez M7 capsule to my u47fet. I will try to get back to you with the results

 

[lyricalgeek]

Does the JFet IDSS matter with this circuit like the U87 as far as Gain and headroom is concerned? I have the following 2n3819 IDSS's 6.80ma, 7.13ma, 7.21ma, 8.29ma and 8.61 ma. What would be the ideal FET IDSS be?

Thanks 

Bump

 

[poctop]

Does the JFet IDSS matter with this circuit like the U87 as far as Gain and headroom is concerned? I have the following 2n3819 IDSS's 6.80ma, 7.13ma, 7.21ma, 8.29ma and 8.61 ma. What would be the ideal FET IDSS be?

Thanks 

Bump

6.80ma

Best,
Dan,

 

[burn4ever]

Hi fellas,
what kind of capsule can or should I use for this nice U47-FET Project and were can I get them?

 

[micaddict]

Hi fellas,
what kind of capsule can or should I use for this nice U47-FET Project and were can I get them?

If you want to stay close to the original you need a K47 capsule. The cheapest ones are China made; the most expensive one is the K47/49 from Neumann itself.

Between those extremes there are other options. 
And worth mentioning are the hybrids (best of two worlds) designs by BeesNeez (K7; K47 meets M7) and tskguy (double backplate K47).

 

[kante1603]

@ burn4ever:You should update your profile.Where are you located?I'm happy with my Thiersch M7,available here in germany.


Udo.

 

[micaddict]

Yes, M7 was K47's predecessor. It was never in the U47fet, but it has a similar vibe.
Thiersch does those well.

 

[burn4ever]

Where are the 18pf Styroflex/630V and  33pf styroflex/630V, that are mentioned above, in use?
Can´t see no one at this documentation.

 

[poctop]

Where are the 18pf Styroflex/630V and  33pf styroflex/630V, that are mentioned above, in use?
Can´t see no one at this documentation.

when i had done the demonstration of mounting the pcb i did not have them available ,
but they are used in this build  for C2 and C3,
hope this helps, see schematic,
Best,
dAn,

 

[burn4ever]

Where are the 18pf Styroflex/630V and  33pf styroflex/630V, that are mentioned above, in use?
Can´t see no one at this documentation.

when i had done the demonstration of mounting the pcb i did not have them available ,
but they are used in this build  for C2 and C3,
hope this helps, see schematic,
Best,
dAn,

Alright, I see.
I wonder cause at the PCB PDF the 18pf and 33pf (C2, C3) are declared with 160V and not  with 630V

 

[poctop]

Where are the 18pf Styroflex/630V and  33pf styroflex/630V, that are mentioned above, in use?
Can´t see no one at this documentation.

when i had done the demonstration of mounting the pcb i did not have them available ,
but they are used in this build  for C2 and C3,
hope this helps, see schematic,
Best,
dAn,

Alright, I see.
I wonder cause at the PCB PDF the 18pf and 33pf (C2, C3) are declared with 160V and not  with 630V

160V there will also be fine ,  most of the styroflex available are 50V please avoid those
I supply 630V they are small package and much more robust.
Best,
Dan,