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

[MatthisD]

Regarding the pad, do you already have the parts listed in the BOM? if not you can substitute the 2 capacitors and 2 resistors for one of each by choosing values to emulate the unpadded position and jumper across the unstuffed component pads which would mean omitting R2,C2 and installing a bridge across one or the other.

 

[muffy1975]

Hey thanks for that.


I have the 100m and the 200m and the 20m all connected together and i have the 33pf and 18pf all connected together too. Seems to be working out.


Cheers


Michael.

 

[MatthisD]

No problem, you have five components there where two would do the job but you have already paid for them so no need to replace.

 

[Jim50hertz]

Got mine up and running this morning, Beesneez K7 and Cinemag Trafo.

Sounds great! I can see why these are so favoured on bass amps, sounds great on my B15.  Great pickup

I'm very happy, thanks for this Dany  8)

 

[poctop]

Thanks To my Brother , I should have some 47Fets PCB available soon,
Best,
Dan,

 

[poctop]

New Run of this are on their way ,
Best,
Dan,

 

[poctop]

Finally Received a Short U47 FET Prototype Body From Oliver At AMI ,

i have sent the mic to higher authorities to get it evaluated, So Far So Good,

I should hear back soon,

Best,
DAn,

Oliver Archut U47Fet Short Body Prototype

 

[Melodeath00]

Awesome! Probably a fairly expensive body, though

 

[poctop]

Awesome! Probably a fairly expensive body, though

Actually Have no idea
DdD

 

[Steph.B]

Holy cow this sure looks nice !  8)

Wonder if the body would sell separately.

It will be a hard time to choose between this one and the GT-2B V.2 Chunger is getting made...

 

[Melodeath00]

Dany, which tranny is in that prototype?

 

[poctop]

Holy cow this sure looks nice !  8)

Wonder if the body would sell separately.

It will be a hard time to choose between this one and the GT-2B V.2 Chunger is getting made...

I am sure Both will mic body will be awesome knowing that Chunger has so much attention to details,
the AMI one is sort of a long shot , i have no deadline for those neither a price and the volume will be probably pretty limited for a starter. My Bet is that Chunger will have a Nice stock of the Gt-2B before this one shows up. this is I guess just a Primer of somthing coming but I really have no deadline as everyone knows that Oliver is a very Busy Man,


The transfo I have used is the T47 from Oliver ,

Best,
dAN,

 

[poctop]

I should have them as of tommorow ,
Best, 
Dan,

 

[poctop]

they Arrived,
Best,
DAN ,

 

[Leer]

Hi Dany.
How do I pick the right transistors? Highest possible HFE or?
And how about the trim resistor?
Best Regards,
Peter.

 

[poctop]

Hi Dany.
How do I pick the right transistors? Highest possible HFE or?
And how about the trim resistor?
Best Regards,
Peter.

Pick the highest HFE. but in reality according to the spec sheet of the transistor use in the bom they are in a class where the hfe should be meet so it is not a worry,  you can skip the trimpot and replace with the proper resistor also in the bom ,
look on page 1 of this thread and you will find explanation regarding this,
Best,
dAN, <

 

[dandeurloo]

Has anyone been able to confirm the polarity is correct on these when the AMI transformer is wired as below?  I have mine wired this way and I have the OUTPUT pads to XLR wired Pin 1 to pin 1, pin 2 to Pin2, Pin 3 to pin3. 

In headphones it seems to be out of phase with other known mics.  I would love to know if it AMI is correct or not?

AMI Transformer wired:
D to pad 3
C to pad 4
A to pad 1
B to pad 2

 

[poctop]

Has anyone been able to confirm the polarity is correct on these when the AMI transformer is wired as below?  I have mine wired this way and I have the OUTPUT pads to XLR wired Pin 1 to pin 1, pin 2 to Pin2, Pin 3 to pin3. 

In headphones it seems to be out of phase with other known mics.  I would love to know if it AMI is correct or not?

AMI Transformer wired:
D to pad 3
C to pad 4
A to pad 1
B to pad 2

According to these this is correct,
it should be in phase,  maybe you have made a mistake with the xlr connector and not the transfo, double check to make sure,
hope this helps,

Best,
DAn,

 

[Graph]

Hi, i am planning to make a pair of u47 fet i saw that MXL 550 may work in the build, did anyone test if it fits right? Or is it there any other cheap donor mic?

Alctrons are not in stock right now

Thanks!

 

[Nyquist]

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