Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)

[e.oelberg]

once again, do we need latching or non latching ?

 

[poctop]

once again, do we need latching or non latching ?

Non Latching ,
Best,
Dany,

 

[Tim Campbell]

I stopped writing on the covers and instead include this.

 

[e.oelberg]

[http://www.banzaimusic.com/Tyco-Axicom-D2N-5V.html/url] 1g insulation resistance

 

[Andydrum82]

The body & capsule arrived from beesneez this week it top quality 

 

[Andydrum82]

I finished wiring it all up this morning.  Here's the back. I haven't bought a tube yet so I can't test it.

 

[Andydrum82]

Here's a picture of the front

 

[trans4funks1]

Beautiful!!!

 

[Veronica Sneesby]

Hey, the mics are coming together nice. Thanks for sharing the photos. We love seeing you all enjoy the body kits and CK12's

 

[poctop]

Actually there is no standard for 7 pin wiring  so you can actually make your own scheme if you will
just make sure it follows the logic from the psu to the mic pcb and you will be fine ,
I just have an habit of following the Neumann scheme for my cable ,  I have wired my cable like this ,
but since this one have 2 pattern control it deviates a little bit from it , but as said if you are using a Gotham cable
reserve the blue wire for Circuit ground and the red wire for the heater as those are the biggest gauge to handle more current
as said you can define your own cable configuration from psu to mic as long as it is following the logic.

here is an example :

1-audio +
2-audio -
3- (Relay control 1) to OMN
cable shield  = up to xlr tab as well
4-heater
5 B+
6 Pattern control ( relay control 2  ) to Fig 8 on mic pcb ,
7 circuit ground

 

[CBarx]

Actually there is no standard for 7 pin wiring  so you can actually make your own scheme if you will
just make sure it follows the logic from the psu to the mic pcb and you will be fine ,
I just have an habit of following the Neumann scheme for my cable ,  I have wired my cable like this ,
but since this one have 2 pattern control it deviates a little bit from it , but as said if you are using a Gotham cable
reserve the blue wire for Circuit ground and the red wire for the heater as those are the biggest gauge to handle more current
as said you can define your own cable configuration from psu to mic as long as it is following the logic.

here is an example :

Perfect, Thanks a ton.  I'll upload pictures after the build is complete.  Should be sometime later today.



1-audio +
2-audio -
3- (Relay control 1) to OMN
cable shield  = up to xlr tab as well
4-heater
5 B+
6 Pattern control ( relay control 2  ) to Fig 8 on mic pcb ,
7 circuit ground

 

[poctop]

Actually there is no standard for 7 pin wiring  so you can actually make your own scheme if you will
just make sure it follows the logic from the psu to the mic pcb and you will be fine ,
I just have an habit of following the Neumann scheme for my cable ,  I have wired my cable like this ,
but since this one have 2 pattern control it deviates a little bit from it , but as said if you are using a Gotham cable
reserve the blue wire for Circuit ground and the red wire for the heater as those are the biggest gauge to handle more current
as said you can define your own cable configuration from psu to mic as long as it is following the logic.

here is an example :

Perfect, Thanks a ton.  I'll upload pictures after the build is complete.  Should be sometime later today.



1-audio +
2-audio -
3- (Relay control 1) to OMN
cable shield  = up to xlr tab as well
4-heater
5 B+
6 Pattern control ( relay control 2  ) to Fig 8 on mic pcb ,
7 circuit ground

Please do,
we always like to see Picture of completed build here,
Best,
dAn,

 

[CBarx]

Just doing some final adjustments on the PSU before plugging in.  I'm noticing that the B+ voltage at terminal Block 1 is at 200v, which seems high based on what I'm reading.  Using trimming resistor R4, I can get the voltage down to about 173v before the resistor bottoms out.  Any thoughts here, or is sending 200v ok (I thought we were aiming for 120v)?  Thanks in advance!

 

[shaggy]

Just doing some final adjustments on the PSU before plugging in.  I'm noticing that the B+ voltage at terminal Block 1 is at 200v, which seems high based on what I'm reading.  Using trimming resistor R4, I can get the voltage down to about 173v before the resistor bottoms out.  Any thoughts here, or is sending 200v ok (I thought we were aiming for 120v)?  Thanks in advance!

No load? (Mic not plugged in.)

 

[CBarx]

Just doing some final adjustments on the PSU before plugging in.  I'm noticing that the B+ voltage at terminal Block 1 is at 200v, which seems high based on what I'm reading.  Using trimming resistor R4, I can get the voltage down to about 173v before the resistor bottoms out.  Any thoughts here, or is sending 200v ok (I thought we were aiming for 120v)?  Thanks in advance!

No load? (Mic not plugged in.)

Correct.  While I'm posting, it seems that the mic works fine in Cardioid and Omni, but when I turn the power supply to Figure 8 I get nothing.  I've checked to see that the voltage moves from pin to pin as I change polar patterns.  Is this a PTP issue or possibly a capsule wiring issue?

 

[Tim Campbell]

Or a short between the backplates.

 

[trans4funks1]

I revised the schematic drawings today to display poctops wiring pin out suggestions.

As always, if someone notices a need for a correction or edit in the drawings please send me a note so that I can make them as accurate and useful as possible.

Thank you.

 

[poctop]

I am to reprint a little batch of those ,
let me know if any interest so i could adjust qty to fit the need,
Best, 
DAn,

 

[mgronroos]

I agree that we could need some easy-to-read wiring diagrams for all the projects that require an extrernal PSU.
It is not that many mics, so I think it would be manageable to make one for every type.

I wouldn't have felt secure about the wiring of my 251 if it wasn't for your schematic drawing, Trans4funks1, so I very much appreciated it. Thx Again! 
And feel free to post your revised version when they are done since I am about to build two more of these babies. 

Cheers!
//Michael

 

[poctop]

thanks to Trans4funks1 for this nice work. 

Microphone DiaGram
https://cdn.groupbuilder.com/groupdiy/u/39511/58d1402a06461.pdf

PSU DiaGram
https://cdn.groupbuilder.com/groupdiy/u/39511/58d02819944c5.pdf

Best,
Dan,