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

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poctop

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If anyone have a suggestion on makinf this pcb more universally mic body friendly i am open to suggestions as i did put a temporary hold on it to ask this question ,

Let me know as soon as possible ,  i tought i could change the hole or put more hole or something like that ,

Please Let me as soon as you guys Can,

Cheers,
Dany,
 

MatthisD

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poctop said:
MatthisD said:
poctop said:
I beleive the MXL is 47mm outer that should leave enough room for the 44mm PCB but this will be part of the experiment on MXL body type For sure.

DAn,

The se2200a body is the same diameter. The PCB mounting holes are only 29.5mm apart. I think the 44mm PCB would have to be trimmed down by a couple of mm on each side unless you can mount the PCB right on the centre diameter some how.
Matt

The things is i have no clue of the railing dimension inside all i was refered too is the Alctron PCB size and they have been created according to that at this point ,  i did a small batch tough so if they are any correction in term of  dimension i will be open to suggestion no problem,
Dany ,

I thought that info might be useful to others if they were planning to use a 47mm body. I'll either do a veroboard job or get a larger body for your PCB thanks.
 

poctop

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Indeed this is usefull information  :) ,  could you take a picture and dimensioned of the railing,  maybe i could come up with something ,  i really wished those railing be standard in those mic,

Dany,
 

MatthisD

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I don't know if this body size is the same that other brands use but heres some measurements.
Do you know the price of the Alctron body? also do you know where to get the 220M resistor?

distance between holes
one rail to the other: 29.5mm
between holes on single rail: 35mm

width from one rail to the other,
outside: 37.5mm
inside:29.5mm
 

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mouse

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possibly in for 2. first time mic project for me and not sure how difficult it will be.
 

atticmike

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MatthisD said:
poctop said:
MatthisD said:
poctop said:
I beleive the MXL is 47mm outer that should leave enough room for the 44mm PCB but this will be part of the experiment on MXL body type For sure.

DAn,

The se2200a body is the same diameter. The PCB mounting holes are only 29.5mm apart. I think the 44mm PCB would have to be trimmed down by a couple of mm on each side unless you can mount the PCB right on the centre diameter some how.
Matt

The things is i have no clue of the railing dimension inside all i was refered too is the Alctron PCB size and they have been created according to that at this point ,  i did a small batch tough so if they are any correction in term of  dimension i will be open to suggestion no problem,
Dany ,

I thought that info might be useful to others if they were planning to use a 47mm body. I'll either do a veroboard job or get a larger body for your PCB thanks.

dunno what you're getting at but the original u47 measures 63mm in diameter and the u87 (just comparing it with a similar build) at 56 / 57mm. Meaning that the U47 was even bigger in both diameter and length. Also, there are lots of big clones out there and well if the pcb is rather small, that wouldn't be too bad since you'd just have to add a little more metal to the pcb holder.
 

MatthisD

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atticmike said:
Also, there are lots of big clones out there and well if the pcb is rather small, that wouldn't be too bad since you'd just have to add a little more metal to the pcb holder.

That would be up to the PCB designer, whether there is enough space to fit the components onto a 27mm or so, useable PCB width. Might be easier not to kill two birds with one stone but whatever pleases the crowd!
 

tomas1808

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Poctop,

What about the polarization voltage? Don't you need 60+ volts for the capsule? I am quite a newbie but I know Igor was wondering about this too.

BTW, what capsule would you recomend? Also what FET is the "82808000224" on the schematic?

I too vote for the MXL 550 as a donor body. Its even cheaper on Amazon.com!

Really interested, will probably be my first DIY condenser  8)

Thanks!
 

poctop

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tomas1808 said:
Poctop,

What about the polarization voltage? Don't you need 60+ volts for the capsule? I am quite a newbie but I know Igor was wondering about this too.

BTW, what capsule would you recomend? Also what FET is the "82808000224" on the schematic?

I too vote for the MXL 550 as a donor body. Its even cheaper on Amazon.com!

Really interested, will probably be my first DIY condenser  8)

Thanks!

The goal of this project was to recreate the faithfull electronics of the U47FET, and since this mic will be mainly used for Kick drum, Bass Cab and stuff that kick and rocks hard. the 40V polarisation is not an issue at all and will even be favorable to the cause ,  I am mentionning officially that what you see on the U47FET schemo is what you will get  no more no less except  that Circuit will allow Bias for the FET (2N3819) , this is will be a cardiod only mic like the orignal was with a -10db pad,  the capsule based for this project is the K47 Type  as the U47 as well or the predecessor the (ChuckD) M7 capsule ,  but i am sure an M7 capsule will end up in mine ,  I will also be able to utilise the best side of those K47 laying arround.

can't wait to build this and put it in front a Kick Drum,  :p
Cheers,
Dan,
 

tomas1808

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Still not 100% clear:

Does the original U47 FET use the same capsule as the tube version (K47) but with 40V polarization instead of 60V?

Or does the original simply use another capsule suited for the lower voltage?

In other words, I don't understand if we are building a "100%" clone, or an "hybrid" (in case the original uses a different capsule or somehow manages to rise the polarization to 60V)

Also, how good will this clone be for vocals? I'm looking for a vocal mike  :D

Thanks again!!




 

poctop

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tomas1808 said:
Still not 100% clear:

Does the original U47 FET use the same capsule as the tube version (K47) but with 40V polarization instead of 60V?

Or does the original simply use another capsule suited for the lower voltage?

In other words, I don't understand if we are building a "100%" clone, or an "hybrid" (in case the original uses a different capsule or somehow manages to rise the polarization to 60V)

Also, how good will this clone be for vocals? I'm looking for a vocal mike  :D

Thanks again!!

The capsule is exact same as tube version or the FET it is a standard K47 or M7 type the polarisation with the original schemo is 46.5V  What has been added is a bias point so you dont have to select your FET to match the fix bias value of the original schemo,  What is important for the capsule is to be 72pf not the polarisation voltage,

hope this helps,
Dan,
 

tomas1808

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mrcase

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how about that one? doen´t look too bad...
http://www.ebay.de/itm/MC-700-Studio-Kondensator-Mikrofon-Niere-Kugel-Acht-/300779473378?pt=DE_TV_Video_Audio_Mikrofone&hash=item4607da89e2#ht_2989wt_1414
 

poctop

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I should be getting a small run next week ,  can't wait to see this thing in action in front a my super kick 24*22
will keep you posted,
dan,
 

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