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

[micaddict]

Yep, there is a small lobe at the back.

 

[micaddict]

OK, I listened to the spoken samples. Eric's new capsule sounds more detailed for sure. But in all fairness, the RK-7 is a dark sounding capsule. It was made to have more treble roll off than the RK-47. And I'd say that Eric's capsule is a little brighter than a regular K47 (first impression, mind). To me it not only looks, but also sounds like a cross breed between the K47 and K67. What I'm trying to say is that the added treble as opposed to the RK-7 helps the sound being more detailed. That said, after EQ-ing the RK-7, I think Eric's would still sound more classy.

 

[poctop]

If you guys like the mic i do still have a couple of PCB left 
and some corresponding styroflex cap kit.

Best,
Dan,

 

[tskguy]

Micaddict

Yes I would agree with on all fronts! I actually thought the Microphone parts rk7 sounded pretty good in this mic, it sounded pretty bad in the mk47 tube mic Wave built. My capsule does have a bit more air up there... I am attaching a frequency chart that actually is comparing my capsule in a G7 circuit against an original u47 with a neumann 47 capsule!! I completely understand its not the best comparison but you can at least see the plot.

 

[MicDaddy]

Sweep time of 2218s 

 

[tskguy]

Funny you noticed that.. Yep that is a 37 minute sweep. It is the most detailed sweep I ever seen.
To add a bit of color this was done by the acoustic department at Colombia college here in Chicago.

Eric

 

[3nity]

Tsk whats the cost of your capsule?

 

[tskguy]

The cost is 250 plus shipping and Paypal fees.

 

[micaddict]

Thanks for posting the chart, Eric. Yes, different circuits (and likely different headbaskets, too?), so it's apples and oranges to some extent, but it does help.
There are some dips there that show in both plots, so I guess that's the room. The U47/K47 is recessed around 8kHz which is right where sibilance resides. This dip could be in the room too, but it's what you'd expect so I assume this one is for real. It is also the area where K67s have a(n extra) lift and that's obviously not the case here. Then there's a subtle peak at 10k or so and then the roll off. Quite typical for a U47, I'd say. However, there's no broad mid/high-mid bulge here, which could be caused by the room or other circumstances.
Your capsule (in the G7) shows the 7-8k dip as well, albeit a little less pronounced. And the 10k lift comes a little "sooner" (towards 9k actually), though not so soon that it would cause noticeable sibilance problems. And then yours has an extra, subtle peak beyond 10k which will add some extra air over the U47 and especially over the RK-7 capsule.

 

[tskguy]

Micaddict,

I dig the assessment. It's interesting that my capsule ended up with a bit more air, I also feal the midrange is bit more in a pleasing way as well. Almost more modern sounding but sill the Neumann sound we all know and love!

Eric

 

[micaddict]

Yes, the extra bit of air is interesting, especially if you used standard 6 micron Mylar. OK, different circuits.

BTW it seems your small holes are a little smaller, if that makes sense. Assuming I'm seeing that right, was that a deliberate choice or more of a practical one due to the available "drill bit" sizes? Please excuse a possibly poor choice of words.


Henk

 

[tskguy]

Micaddict

It's interesting you think that, the small holes are actually the exact same size as an original 47
The larger blind holes are actually bigger. The reason why is a bit of secret sauce and a big part of the dual backplate design. Any case I am pretty pleased and don't plan on changing the design..

Let me know when you want one?  ;D ;D

 

[micaddict]

LOL Believe it or not, but I was going to add the other possibility, i.e. the "large" holes being larger.
Anyway, point is there's a "bigger" difference in size. And if that works, which it obviously does, do leave it that way.

Using it in clones is one thing, but even more interestingly IMO is which of the big boys will be first to design a new microphone around it.
Only a matter of time, I say.

 

[Joekkel]

hi folks,

if i use a cm-13101 trafo with this build, am i right with these connections from the transormer to the pcb (i just looked at the pics of tskguy's post #309):

brown - pad 1
red - pad 2
yellow - pad 3
orange - pad 4
black - glink

thx and many regards

 

[tskguy]

That works great for my mic! There is data sheet on the cinemags site as well.

 

[KasperNyhus]

YES! I finally made it...  ;D

I took a T-bone sct700 and modded it to look a bit more u47fet stylish... 

Thanks Dan for another fine mic project!

I now got this little family:

 

[baadc0de]

YES! I finally made it...  ;D
...
I now got this little family:

Hey mate, where did you get the 3-pin XLR insert? Care to explain a bit on making of the mount? I made two SC700 -> U47FET mics already, looking to get them to the next level

Also thanks and big props to Dan for making these PCBs available and supporting them.

 

[useme2305]

cool stuff! what are those u87/67 type donor bodies?

 

[KasperNyhus]

I bought two of these in Germany: http://www.musicstore.com/en_EN/EUR/Fame-Studio-C02-Large-Diaphragm-Microfon/art-REC0001545-000?recId=daf53a13-053c-4dba-bf77-25a842f9df7e

@baadc0de
I will take some more pictures later so you can see what I've done

 

[imo]

Just got my build running. Sounds spectacular! NOw a D67 and the U47fet. I used the Equinox capsule and body(repurposed from an earlier mic), as well as the AMI T49. I saw a solution for mounting the XLR somewhere in the thread a couple of days ago, and cant for the life of me find it now. I have the XLR just hanging for the time being.
Is there an insert for an XLR connector that will allow me to mount it in the Equinox body? 
Ian