Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #700 on: January 13, 2018, 11:21:48 AM »
Thanks for trying with me.
I did not miss r16, I had to rewire it from the other side because I tried too much/too hard to find out what went wrong. Project n2 got everything in place.
The  floating connection have been checked and re-checked on both projects.
And I did clean almost everytime.
But obviously, I do something wrong.
I’m in France.


TillM

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #701 on: January 13, 2018, 11:47:07 AM »
Did you use everything from the BOM?
I Used first  the bc212 at my build, as on the original schematic,
They don’t work. So I take the 550/560 from the BOM.
What happen, when you install a capsule.
Did you check the voltages as shown on the schematic ?

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #702 on: January 13, 2018, 12:02:11 PM »
it looks like you're injecting a large signal.   
:o  :-[
Thank a lot Jeff. I was hitting that poor thing as hard as I can. Shame on me.
Of course,  it now looks like it is working.  :-[   ::)  ;D
I do have work / tests to do to find out if everything is fine but it seems way better.

deveng

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #703 on: January 13, 2018, 01:01:21 PM »
boomfred,

Next thing to do is use some isopropyl alcohol and clean the solder flux off the pcb.   Make sure its very clean as any flux on a high impedance circuit can mess with your signal!

Regards,
Jeff

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #704 on: January 15, 2018, 04:57:42 AM »
So, tests have been run, and everything works perfectly.

My advice : don't try to build this mic while you are trying to repair an Acoustic 126. Levels don't match.  ;)
Did I mention how dumb I am ?

Did you use everything from the BOM?
I Used first  the bc212 at my build, as on the original schematic,
They don’t work. So I take the 550/560 from the BOM.
What happen, when you install a capsule.
Did you check the voltages as shown on the schematic ?
I did stick to the BOM, and of course voltages were perfectly fine.

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #705 on: January 15, 2018, 01:44:16 PM »


how did you make the edges around the transformer? pieces of wood ? and is it black tape?

Thanks,
Baba