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

[poctop]

Looked throught the entire post to find out how to wire the XLR and AMI to the the Mic P.S.B.

GND, = gnd
OMH dont recall this one ???
,FB front backplate
,H+ heater
,A- audio -
,A+ audio +
,P+ Primary +
,P- Primary -
,S- secondary -
,S+ secondary +
,B+  Plate Voltage

Other than the picture in "Reply 121" which kinda helps, I wasn't able to find a concrete answer.
Using the white boards. Any Help?

 

[Winetree]

Thanks for the terms. but where do they connect to the XLR and AMI transformer.

GND, = gnd ( GND tab on XLR )
OMH dont recall this one
,FB front backplate ( to front capsule backplate )
,H+ heater ( what pin # on XLR )
,A- audio - ( what pin # on XLR )
,A+ audio + ( What pin # on XLR )
,P+ Primary + ( Red on AMI )
,P- Primary -  ( Red on AMI )
,S- secondary - ( Blue on AMI )
,S+ secondary + ( Blue on AMI )
,B+  Plate Voltage ( What pin # on XLR )

 

[poctop]

Thanks for the terms. but where do they connect to the XLR and AMI transformer.

GND, = gnd ( GND tab on XLR )
OMH dont recall this one
,FB front backplate ( to front capsule backplate )
,H+ heater ( what pin # on XLR )
,A- audio - ( what pin # on XLR )
,A+ audio + ( What pin # on XLR )
,P+ Primary + ( Red on AMI )
,P- Primary -  ( Red on AMI )
,S- secondary - ( Blue on AMI )
,S+ secondary + ( Blue on AMI )
,B+  Plate Voltage ( What pin # on XLR )

I always run my cable the same way on the xlr cable pinout,
1-audio +
2-audio -
3 shield up to xlr tab as well
4-heater
5 B+
6 Pattern control ( relay voltage )
7 circuit ground

For AMI T14 it will be :

Blue , Blue    will be primary + and Primary -
red , red      will be secondary + and secondary -

hope this helps ,
Dan,

 

[Winetree]

Thanks, Dan.
I'll use that as a standard hookup.

 

[mgronroos]

Hi guys!

Now I am actually really confused..  ??? I can't seem to make sense of the PIN-connections here.
I look at the PSU in the build, at #121 and at your cable wiring suggestion here, poctop, and they don't look the same.
What am I missing?

We have the following labeling on the PSU/MIC that need to find the right PIN on the two XLRs:

PSU
Label          7-PIN          3-PIN
__________________________________
B+
H+
Bias
POL
GND
Relay
GNDC
POLV
Pmic
PGND
Switch 1
Switch 2
Switch 3
Switch A


MIC
Label          7-PIN
___________________________
A+
A-
H+
F8
OMN
GND
B+


If we could get the "correct" pinout for each label it would make things a lot easier, and we could all use the same standard in our 251-builds.
Right now, I'm not certain what PINs to connect to what label on the PSU/Mic since I am confused by the pictures and lack of clear information.

Please feel free to use any way of describing this that you find best, as long as we understand what PIN goes where on the PSU and Mic..

Thx a lot! :=)

//Michael

 

[poctop]

Thanks for the terms. but where do they connect to the XLR and AMI transformer.

GND, = gnd ( GND tab on XLR )
OMH dont recall this one
,FB front backplate ( to front capsule backplate )
,H+ heater ( what pin # on XLR )
,A- audio - ( what pin # on XLR )
,A+ audio + ( What pin # on XLR )
,P+ Primary + ( Red on AMI )
,P- Primary -  ( Red on AMI )
,S- secondary - ( Blue on AMI )
,S+ secondary + ( Blue on AMI )
,B+  Plate Voltage ( What pin # on XLR )

I always run my cable the same way on the xlr cable pinout,
1-audio +
2-audio -
3 shield up to xlr tab as well
4-heater
5 B+
6 Pattern control ( relay voltage )
7 circuit ground

For AMI T14 it will be :

Blue , Blue    will be primary + and Primary -
red , red      will be secondary + and secondary -

hope this helps ,
Dan,

I actually made a little mistake here as there is 2 wire for the relay control , i will be making a drawing in a short moment ,
to make this all clear , for the mean time i will dit this post to add the proper xlr config for this particular build,

edit:

1-audio +
2-audio -
3- (Relay control 1)
cable shield up to xlr tab as well
4-heater
5 B+
6 Pattern control ( relay control 2  )
7 circuit ground

 

[trans4funks1]

These drawings may be helpful:

If anyone finds any mistakes in these drawings please make a note of it so that they can be corrected.

 

[mgronroos]

Thanks, trans4funks1!

This was exactely the info I was searching for. Very easy to follow, well done!

I finally came around tonight to do the wiring, and gave the 251 a nice Gotham cable too. 
Just right after calibration, this mic sounds heavenly right away!

I will let it burn in for a few days and then take it to the studio for testing.

Best,
Michael.

 

[trans4funks1]

Hi Michael,
I'm glad it worked out  well.

 

[poctop]

Hi Michael,
I'm glad it worked out  well.

trans4funks1  your the best ,
Thanks for your help in this matter,
Best

 

[dougch]

I have a couple of questions about the component values. Looking at the picture gallery on the Telefunken USA site, I see that they are using what appears to be 50M resistor on the grid, the 8M resistors are changed to 10M, the 4800pF cap is changed to 10000pF (0.01uF), coupling cap is 2uF and there is no sign of the 100pF cap. Do these changes have a major or minor influence on the circuit as a whole? If this question is too broad, forgive me, I am just curious.

I am also curious about building a M251 model with a 5840 for the tube. Would this be difficult? This would be a second build.

 

[mgronroos]

Hi Guys!

I just picked up my 251 from the powder coater today.
After a week of bad sleep I can say that I am happy with how mintness the of the mic turned out!  ;D
Beige with a tint of green, pretty much like an original ELA M, just as I wanted. VERY happy camper!

Now I definitely want to powder coat my other mics too..
The light ivory you use, Kidvybes, looks very tempting indeed for the C12 stereo pair.

Best,
Michael

 

[kidvybes]

Hi Guys!

I just picked up my 251 from the powder coater today.
After a week of bad sleep I can say that I am happy with how mintness the of the mic turned out!  ;D
Beige with a tint of green, pretty much like an original ELA M, just as I wanted. VERY happy camper!

Now I definitely want to powder coat my other mics too..
The light ivory you use, Kidvybes, looks very tempting indeed for the C12 stereo pair.

Best,
Michael

...Looks Great, Michael!...glad it turned out to your liking!

BTW, I used "Cream" on my C12...my other 2 mics were closer to that color you just got...

 

[Dylan W]

This looks great. Do you know what the color code/name is that they used?

Hi Guys!

I just picked up my 251 from the powder coater today.
After a week of bad sleep I can say that I am happy with how mintness the of the mic turned out!  ;D
Beige with a tint of green, pretty much like an original ELA M, just as I wanted. VERY happy camper!

Now I definitely want to powder coat my other mics too..
The light ivory you use, Kidvybes, looks very tempting indeed for the C12 stereo pair.

Best,
Michael

 

[kidvybes]

This looks great. Do you know what the color code/name is that they used?

...here's one of the more popular powder-coat supplier charts:
http://www.nortekpowder.com/pdfs/NortekColorCatalog-2011.pdf

...kinda looks like the "Light Ivory" on this chart...I used that shade on two of my mics, and it matches BeesNeez ELAM-style "Seamist" body color exactly...

 

[mgronroos]

Thx! It actually looks just a bit darker on the photo than it really is due to the low light.
In daylight it looks more like a beige with just a tint of green in it. Very nice with a vintage vibe.
I will post better pictures soon..

Dylan W, I chose from the chart in Kidvybes link, and the color code is RAL 1000
Homepage: http://www.ralcolor.com

I definitely like the RAL 1015 Light Ivory. Contender for the C12!

//Michael

 

[e.oelberg]

looks like the panasonic relays are rate with 100m isolation resistance, I doubt thats good enough, but it is not so difficult to find relays with 1g or higher insulation resistance

 

[poctop]

looks like the panasonic relays are rate with 100m isolation resistance, I doubt thats good enough, but it is not so difficult to find relays with 1g or higher insulation resistance

I was actually suggested those by Oliver , but if you can find  better I am open to suggestion as always ,
they were chosen as a compromised between power package and isolation ,

Let me know,
Best,
Dan,

 

[trans4funks1]

I like to find some relays with actual solder tabs that were small enough for me to fit into a Beez Neez 60mm body or a Chi-Com 47 donor.

If anyone has a suggestion I'll appreciate it. I keep realizing my eyes are fuzzy when I am searching through the catalogs.

 

[e.oelberg]

yes looking through a catalogue is a horror. I found these 1000g isolation resistance !!
http://de.farnell.com/standexmeder/dip05-2a72-21l/reed-relais-5v-2xschliesser-ohne/dp/1079443