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

[3nity]

NOw a D67 and the U47fet

And whats the mic you're talking about then??
this is the U47Fet thread! lol.

 

[EvLoutonian]

Hehe.. I was wondering the same thing..
I think he means that he already had the D67, and now he also has the U47fet completed.

 

[imo]

Sorry. Meant to say i have 2 of Dans mics(including the D67 and the fet47).
My fet47 needs an insert for the XLR to fit into the Equinox body

 

[EvLoutonian]

Keen to hear if anyone comes up with a good solution for installing a normal three pin XLR in the Equinox bodies.

I was just going to make a conversion cable for my U47fet build, with Binder connector at the mic, and XLR male at the other end.

 

[uffetuff]

I'm using a Golden Age TC-1 as donor body. I thought of buying a t.bone but I had this one broken laying around so I thought it was a better (cheaper) choice. I think I'm pretty much done with the soldering of the PCBs. Just have a few questions before I proceed.

I just recently built a DU87 where I needed to measure the FET to be in a desirable value. Is that needed here too? I already put it place, but I have a bunch more.

The LC jumper, is that for Low Cut?... if not, what?

There are two jumpers for PAD. S1A and S1B, how do I use those?
The TC-1 has two switches for Pad and Low cut. I'm thinking about using those if I can figure out how the S1-things works.

I have the RK7 capsule from microphone-parts.com. I read that if you connect both front and rear to the same, you get omni. Will that work with this, or will it get weird since it's super cardioid?

Sorry for stupid questions. But I there wasn't as much useful info about this as the DU87.

Edit: deleted one question, too stupid

 

[poctop]

I'm using a Golden Age TC-1 as donor body. I thought of buying a t.bone but I had this one broken laying around so I thought it was a better (cheaper) choice. I think I'm pretty much done with the soldering of the PCBs. Just have a few questions before I proceed.

I just recently built a DU87 where I needed to measure the FET to be in a desirable value. Is that needed here too? I already put it place, but I have a bunch more.
you can select for low IDsS as the U87 does but there is no bias it is a self bias circuit

The LC jumper, is that for Low Cut?... if not, what? Yes Low cut

There are two jumpers for PAD. S1A and S1B, how do I use those?
The TC-1 has two switches for Pad and Low cut. I'm thinking about using those if I can figure out how the S1-things works.
The pad uses a dpdt switching double pole double throw,  so in order to use it you need this kind of switch or 2 separate jumper 1 on S1a and the other one in S1b those will be be in the same position for no pad and the other same position for pad if your switch is a dpdt you can trace it with the schematic
 

I have the RK7 capsule from microphone-parts.com. I read that if you connect both front and rear to the same, you get omni. Will that work with this, or will it get weird since it's super cardioid?
you can try because i did not myself where did you read that,  i really like the u47FEt for his supercardiod behavior tough

Sorry for stupid questions. But I there wasn't as much useful info about this as the DU87.

 

[uffetuff]

The pad uses a dpdt switching double pole double throw,  so in order to use it you need this kind of switch or 2 separate jumper 1 on S1a and the other one in S1b those will be be in the same position for no pad and the other same position for pad if your switch is a dpdt you can trace it with the schematic
 

Ok, but if i leave those alone with nothing on them, does that mean no pad? I think i have one of those switches from a slaughtered mic. I'll try.


you can try because i did not myself where did you read that,  i really like the u47FEt for his supercardiod behavior tough

I don't want to make it omni full time. Just thinking abou the possibilitys to add a switch for it. I reda about it on microphone-parts.com on the info page for the RK7.
"Alternatively, wire the rear diaphragm together with the front, making your Cardioid microphone into an Omnidirectional."

Plus one more question. The isolation pin should be wired to the g-link on opposit pcb, right?

 

[Enchilada]

Keen to hear if anyone comes up with a good solution for installing a normal three pin XLR in the Equinox bodies.

I was just going to make a conversion cable for my U47fet build, with Binder connector at the mic, and XLR male at the other end.

I used a three pin insert from an XLR cable connector I got from Jaycar. A lot of XLR connectors use the same inserts.

 

[EvLoutonian]

Cheers, Enchilada!
Do you mind posting a pic of how you got the XLR insert to stay securely in the base of the Equinox body kit?
Much appreciated.

I used a three pin insert from an XLR cable connector I got from Jaycar. A lot of XLR connectors use the same inserts.

 

[Enchilada]

Finally got around to building my one of these using the Cathedral Pipes capsule and an Alctron MK47 body. I'll pop some photos and recording samples in my build thread soon. So far, I've noticed that the proximity effect isn't particularly flattering on my voice. Although it seems a pretty detailed sound, it is a touch muddy for my liking. I've used a transformer that came out of a stock Apex 460 so that probably doesn't help. I've got a T49 on order though so we'll see if that's the problem.

 

[Enchilada]

Cheers, Enchilada!
Do you mind posting a pic of how you got the XLR insert to stay securely in the base of the Equinox body kit?
Much appreciated.

I used a three pin insert from an XLR cable connector I got from Jaycar. A lot of XLR connectors use the same inserts.

I'm using the Alctron MK47 mic body although I was sure it used the same 7 pin connector. I'll make sure I take photos of it in my thread.

 

[poctop]

Plus one more question. The isolation pin should be wired to the g-link on opposit pcb, right?

Nope the G-Link here is just an extra grounding pad not to be confused with the Gate link in the D-U87,

hope this helps,  the isolation pin on the 47FET Just supports the HZ component that connet to the FET ,

Best,
Dan,

 

[Enchilada]

While you're about Dan, how important is it that the 18pf is Styroflex? I've used Silver Mica because I couldn't find Styroflex. I've got some spare 22pf Styroflex, could they work?
Also, do I really need the isolation pin? I couldn't find one of those either so I just connected everything over air.
One more Q, I haven't been using my AMI U47 too much, how do you think a T47 trafo would go in this mic?

 

[poctop]

While you're about Dan, how important is it that the 18pf is Styroflex? I've used Silver Mica because I couldn't find Styroflex. I've got some spare 22pf Styroflex, could they work?

they will work fine, Silver mica is a very high end capacitor might just not be the exact same coloration , the filter RC calculation or feedback will just be a tiny tad different but that's it

Also, do I really need the isolation pin? I couldn't find one of those either so I just connected everything over air.

Yes you can leave the connections in the air.

One more Q, I haven't been using my AMI U47 too much, how do you think a T47 trafo would go in this mic?
the ratio might be a bit off if we compare 6.5:1 to about 9:1 but IMO it always worth a try DIY Rules
might you be able to wire it in 11:1 tough 

Hope this helps,
Best,
Dan,

 

[Enchilada]

Can I? It is dual bobbin. How would I go about doing that?

 

[HellfireStudios]

Can I? It is dual bobbin. How would I go about doing that?

Look up the datasheet on that particular transformer. Although, if it doesn't have taps, and the associated extra leads, you may not be able to do anything about it.

-James-

 

[Enchilada]

Nothing about 11:1 on the spec sheet.
http://www.tab-funkenwerk.com/id81.html

 

[digdoug]

Hi Guys,

I have done a bit more investigating on donor bodies and these seem pretty good:

Aurcyle A620, Sterling Audio ST51 both are available from amazon really cheap

i just wondered on the sizes inside for mounting the PCB's.

any info very welcome.

regards

Spence.

I have a Sterling ST-55 here that I was hoping would be large enough to accommodate the pcbs, but it's not going to happen.  Inner diameter (42mm) looks too small.  The ST-51 might be the same body without the switch cutouts. (?)

Inner diameter is 42mm.  Rails are 39 at their widest.

 

[poctop]

I did post the pcb dimension on the site , the pcb were specicifically made for the GT-2B alias thomannsct-700 and the like,

Might also Chunger from the groupdiy might have some more of those,

http://www.groupdiy.com/index.php?topic=50015.0

or

http://www.thomann.de/gb/the_tbone_sct700_roehrenmikrofon.htm

other mxl fit the bill as i can recall the mxl4000 Large like a glove ,

here is a link on it ,

http://www.mxlmics.com/microphones/900-series/4000XL/

 

[Joekkel]

d-u47fet finished! beautiful sound!! thanks poctop, this is my third mic from you and it's killer like the other two!!

http://www.facebook.com/photo.php?fbid=10201801775952918&l=eec8c3b02e
http://www.facebook.com/photo.php?fbid=10201801776632935&l=97ab2ac92f
http://www.facebook.com/photo.php?fbid=10201801776152923&l=2136252469