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

[roger.unc]

Hi - I've just "completed" my build of the U47FET. The mic passes audio but cuts out at regular intervals every few seconds. I injected continuous white noise into my amp and recorded the result with the mic - dropbox link below. I've also attached a picture of the waveform. Any ideas on what could be causing this? Bad styroflex caps? Thanks. --Roger

https://www.dropbox.com/s/y3yvmas35iub89o/u47FET_test.mp3?dl=0

 

[poctop]

Hi - I've just "completed" my build of the U47FET. The mic passes audio but cuts out at regular intervals every few seconds. I injected continuous white noise into my amp and recorded the result with the mic - dropbox link below. I've also attached a picture of the waveform. Any ideas on what could be causing this? Bad styroflex caps? Thanks. --Roger

https://www.dropbox.com/s/y3yvmas35iub89o/u47FET_test.mp3?dl=0

you probably solder the HZ resistor in the wrong pad , No R+ pad is using the 220M resistor ,

Dan,

 

[roger.unc]

Bingo! I did not solder the correct pad for the 220. Funny how I can read the directions, look at the picture, and still not understand how it's supposed to be done. Many thanks! The mic sounds great.

 

[plinker]

Hey folks,

Has anyone measured the noise performance on this build?  I realize it's the same circuit as the original Neumann product, but with all the low noise components available now I'm curious how it compares.

Thanks,
Jim

 

[Rlucas41]

Hello folks,
I wanted to post a picture and sound clip of my U47fet... what a great mic this is! I have built two of them now both with the Cinemag MM13101 transformer and the MicAndMod vintage 47 capsule...
The clip is of an acoustic guitar track I did with a Gibson J45>U47fet>Redd 47>RS124>RME Fireface 800

https://www.dropbox.com/s/wfcpbvmfqoofzi3/Berts%20Acoustic%20guitar_05.wav?dl=0

 

[vinylwall]

My 4th U47FET build.  MXL V89 donor body, MP RK-47 capsule, Cinemag CM-13101 transformer...

 

[vinylwall]

This shows the modifications to the inner rails and the assembled mic...

 

[TLRT]

Drum OH's / acoustic guitars / vocals were all recorded with my u47fet clones, band was number one in the local radio charts:

https://www.youtube.com/watch?v=VnlMOa-GiXA

 

[poctop]

Drum OH's / acoustic guitars / vocalls were recorded with my u47fet clones, band was number one in the local radio charts:

https://www.youtube.com/watch?v=VnlMOa-GiXA

Aweseome,
Best,
DAn,

 

[Enchilada]

Hey guys,

Been a while since I've been asking these parts. I built me U47 FET probably over a year ago now and while I love the sound it is soooooo noisy so it's almost impossible to use. Anyone else have noise issues?

I took plenty of care building it. Constantly cleaning with alcohol. Could I have a dud FET? Or could it be a bias problem? I used a jumper instead of a trimmer because I don't have a scope.

Cheers,

Kris

 

[tmuikku]

Hey guys,

Been a while since I've been asking these parts. I built me U47 FET probably over a year ago now and while I love the sound it is soooooo noisy so it's almost impossible to use. Anyone else have noise issues?

I took plenty of care building it. Constantly cleaning with alcohol. Could I have a dud FET? Or could it be a bias problem? I used a jumper instead of a trimmer because I don't have a scope.

Cheers,

Kris

is mic enclosure grounded and to xlr pin 1 only? i haven't built this mic yet but this is crucial on most i believe.

 

[Enchilada]

is mic enclosure grounded and to xlr pin 1 only? i haven't built this mic yet but this is crucial on most i believe.

Yep

 

[Enchilada]

I'm way too lazy to troubleshoot these days. I just ordered a new PCB, hammered out a soldering session and now it's all good  ;D

 

[Andriejus]

I have the same issue. It sounds nice but a lot of ocean noise.
Can I clean pcbs with components in ultrasonic bath with water?

Where did you use a jumper? I used no trimmer and no jumper, maybe there is a problem?

Kind regards,
Andrew

 

[saint gillis]

I have the same issue. It sounds nice but a lot of ocean noise.

Hello, I also had the same issue, so as Dany advised me I cleaned around A B C D E F points, and I also cleaned everywhere high value resistors were involved and around the high-Z zone, I also dug a bit with a cutter and a small screwdriver between the traces involved to make sure the isolation was optimum because my pcb was kind of really dirty... and now the mic sounds perfect...

 

[lp1000]

Hello,

I use a capacitor 18pF and 33pF / 4000V instead 18pf and 33pF / 630 V, it will affect the sound?

 

[deveng]

Just finished up my U47FET clone today.  Worked first power up and is nice and quiet.  I used the GT-2B donor body from Chunger,
a Cinemag 13101 and a Equinox Q47D I got from Skylar quite awhile back.  I've got a 10 song tracking session starting this week and it will make its debut as outside kick.  I was going to use the Q47D for a second MK47 but decided this mic would be a good use of the capsule (will go with either a Beesneez M7 or Thiersch for my second MK47). 

Thanks to Poctop for the kit!  Easy and fun build with great results.

Next mic on the list will be a pair of  U67's.

regards,
Jeff

 

[poctop]

Just finished up my U47FET clone today.  Worked first power up and is nice and quiet.  I used the GT-2B donor body from Chunger,
a Cinemag 13101 and a Equinox Q47D I got from Skylar quite awhile back.  I've got a 10 song tracking session starting this week and it will make its debut as outside kick.  I was going to use the Q47D for a second MK47 but decided this mic would be a good use of the capsule (will go with either a Beesneez M7 or Thiersch for my second MK47). 

Thanks to Poctop for the kit!  Easy and fun build with great results.

Next mic on the list will be a pair of  U67's.

regards,
Jeff

Thanks Jeff for the Nice word always glad to hear those Stories,

regarding the M7 you should check out my New D7 Capsule here

http://www.vintagemicrophonepcbkit.com/Caspsule.html

this is my take on the M7 Capsule.
Let me know then,

Best,
Dan,

 

[deveng]

Dan,

Might just do that!  Price is significantly lower and the feedback appears to be all good for your D7.   

So far I've used a Peluso CEK12 (in a 251 recreation), a Charles/Ulan M7 in my first MK47 and now one of the Q47D's in the 47FET.  All sound really nice.    Still have the U67's to build as well and will need a pair of capsules for those.

Keep up the great work Dan,
Regards,
Jeff

 

[deveng]

I'm setting up a tracking session and while checking all mic connections/routing etc on the drums one of the first things I notice is how quiet this U47 FET is.    The self noise is much lower than most of the mics in my locker. 

Speaking of noise, I can't over emphasize for new builders the importance of clean PCB's.    This includes body oils as well as flux.  Especially in the high impedance sections.    Look closely at the solder pads and make sure no flux remains.  Sometimes its tough to get it all off and may take a good scrubbing to remove all the flux. 

Regards,
Jeff