Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #760 on: June 17, 2019, 07:33:36 AM »
My first test nickel plate version!!
Getting there.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!


duantro

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #761 on: June 17, 2019, 11:25:20 AM »
Looking good Spence! Only thing I would suggest for subtle improvements would be maybe polish some of the machining grooves, or bead blast a matte finish out of the body, and get pan head screws to not snag on anything and look cleaner. Like this photo:

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #762 on: June 17, 2019, 11:41:55 AM »
yeah, i'll try and countersink the bottom ones a bit, top ones are ok.
This test piece didn't come out as well as the other two i've done so far, cleaning the attachment wire each time before plating I have started to do and its much improved.
Will post more photos later, trying to crack through them all and running out of time!!!!
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #763 on: June 17, 2019, 03:17:20 PM »
Ok here’s the first two I’ve finished.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #764 on: June 17, 2019, 03:18:08 PM »
Internal pic
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #765 on: June 17, 2019, 03:19:37 PM »
I’ll do a pic of the round connector as well!!
« Last Edit: June 18, 2019, 05:17:16 AM by Spencerleehorton »
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

duantro

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #766 on: June 17, 2019, 05:31:06 PM »
Ok here’s the first two I’ve finished.
Looks great!

BladeSG

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #767 on: June 18, 2019, 02:33:58 AM »
Anyone use the Beesneez U67-U87 body for this project?

If so, could you please let me know the length (inside) of the body so I can work out if it will fit the PCB and transformer?

Also, is the Beesneez BV11 transformer going to work with the 47 FET as it looks as though the spec is the same as the AMI T49?

Any help greatly appreciated.

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #768 on: June 18, 2019, 05:19:30 AM »
Beezneez bv11 should work fine, it’s 10:1 so it’ll work!!
I’ve not had any experience with them though, maybe someone else could chime in?
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

BladeSG

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #769 on: June 18, 2019, 07:41:46 AM »
Beezneez bv11 should work fine, it’s 10:1 so it’ll work!!
I’ve not had any experience with them though, maybe someone else could chime in?

Thank you.


duantro

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #770 on: June 18, 2019, 02:37:31 PM »
I’ll do a pic of the round connector as well!!
I like the xlr mount, but it is the wrong gender. Should be a male pin connecter, no?

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #771 on: June 18, 2019, 02:42:25 PM »
Your right! Wrong pic, will update with an actual picture of the bottom of the mic don’t worry!!!
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #772 on: June 23, 2019, 07:23:09 AM »
Here's a tip for anybody building this:

It's preferred for solder joints to have a mechanical connection in addition to the solder. If you insert the isolation pin backwards, you can create "j hooks" to wrap the pin and have a more reliable connection.

Thanks,
Josh

TillM

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #773 on: June 23, 2019, 08:00:12 PM »
Good idea, but you burned down your styroflex capacitor with the solder shaft.

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #774 on: June 25, 2019, 09:12:02 AM »
These are my first two, finished polishing as best as i can, will be upgrading tools etc so everything will improve and have learnt a lot.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #775 on: June 25, 2019, 09:12:38 AM »
inside struts and capsule plate.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Spencerleehorton

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #776 on: June 25, 2019, 09:15:42 AM »
3 Pin XLR Connector
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!
Or a snake!!!

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #777 on: July 03, 2019, 10:06:54 PM »
Good idea, but you burned down your styroflex capacitor with the solder shaft.

That's exactly as the styroflex was received. It's not burnt, but the "clarity" setting I raised probably made it look a little goofy. There's no burn mark or anything like that on it.


Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #778 on: July 03, 2019, 10:11:44 PM »
Here's my completed mic. Works perfectly and sounds great with a Beesneez K7 capsule.

Thanks,
Josh

duantro

Re: Neumann U47FET Clone: D-U47 FET Microphone Project PCB Build thread
« Reply #779 on: July 06, 2019, 09:20:51 PM »
I've got one of these assembled and it wasn't working. . I went through and took measurements to compare to Muffy1975's post back on page12 or 13, and Was getting pretty much exactly the same voltages as he was (his didn't work either). I realized that I had a short at pad AA to the screw that I tried to mount to the railing. I pulled that  screw and bracket and after measuring for polarization, I’m getting 15.65v  at AA, and the output is really quiet. Both of my 10M resistors still measure as good. I’ll try to go through and measure all of the transistors again, but not sure where else to look for the low polarization voltage.  I'm using an eab Telefunken 10:1 transformer, and have the higher resistance leads measured going to pad 1 and 2, and the lower resistance measured leads to the xlr pads 3.4. Here are the voltage measurements that Muffy1975 posted a while back:
New measurements

on the 2n3819 T1 i have
drain=  38.8v
source =  23.6v 

on T2 i have 
E= 23.62
B= 22.5
C = 0.592

on T3 i have 
E=38.8v
B=29.57v
C=40.3

T4 i have 
E= 19.7v
b=20.6 v
c= 22.5v

T5 i have 
E=41.1v
B=40.1v
C=20.6v

on T6 i have 
E=0v
B=0.591v
C=20.6v

T7 i have 
E=42.7v
B=42.9v
C=44.74v

and 15.4v from the 10m resistor to the junction with the 1g resistor.
« Last Edit: July 07, 2019, 02:52:20 PM by duantro »


 

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