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

[andybaker28]

Hi there and thanks for the info, I got it figured out. I just finished all the soldering and then when I tried to put it together the body is not even close to fitting because of the relay switches! I saw an earlier post where someone shaved down the edges of the relays, is this the best way to get the body to fit on?

Thanks for any suggestions!

Andy

 

[duantro]

Hi there and thanks for the info, I got it figured out. I just finished all the soldering and then when I tried to put it together the body is not even close to fitting because of the relay switches! I saw an earlier post where someone shaved down the edges of the relays, is this the best way to get the body to fit on?

Thanks for any suggestions!

Andy

Are your relays mounted flush? I'd check that before resorting to filing. It's tight, but mine fit.

 

[JessJackson]

Hi there and thanks for the info, I got it figured out. I just finished all the soldering and then when I tried to put it together the body is not even close to fitting because of the relay switches! I saw an earlier post where someone shaved down the edges of the relays, is this the best way to get the body to fit on?

Thanks for any suggestions!

Andy

mine are mounted flush and i just took the edges down slightly with a soldering iron.

Jess

 

[andybaker28]

Ok , here is some tweaks you can do from original schemtics,

Tweak #1

If your capsule is a bit low end shy for your taste, try to decrease capsule voltage to 55V (reduce the 0.5MOhms to ground),  increase the 30Mohms grid resistor to 300Mohms and put a 100uF on the cathode instead of 22uF. U could increase the output coupling capacitor up to 3.3uF as well ....
with the high end response, assuming your plot is accurate , i would increase the output LP filter by increasing the 120pF to 220pF or even 330pF ... (or more to taste)


Tweak #2

1. Grid to ground resistor higher  100m or 250m
2. Increase or decrease output coupling cap to taste to modify low end response

Hi Dan, I just finished up a 251 and it sounds very good, but I do hope to get a bit fuller low end. I am interested in the mods you have mentioned here, but as this is my first build I am still not able to understand the circuit and or schematic very well. I wonder if you could possibly let me know which resistors and caps could be changed by their part number..

decrease capsule voltage to 55V (reduce the 0.5MOhms to ground) R?
increase the 30Mohms grid resistor to 300Mohms R?
put a 100uF on the cathode instead of 22uF C?
output LP filter by increasing the 120pF to 220pF or even 330pF ... (or more to taste) C?
Grid to ground resistor higher  100m or 250m R?
Increase or decrease output coupling cap to taste to modify low end response C?

I do appreciate it very much, I so enjoyed the build and look forward to many more! Keep up the good work! I have also posted a pro tools session of my build next to a new Telefunken 251 if you are interested to hear!

Thanks

Andy

 

[ding]

Ok , here is some tweaks you can do from original schemtics,

Tweak #1

If your capsule is a bit low end shy for your taste, try to decrease capsule voltage to 55V (reduce the 0.5MOhms to ground),  increase the 30Mohms grid resistor to 300Mohms and put a 100uF on the cathode instead of 22uF. U could increase the output coupling capacitor up to 3.3uF as well ....
with the high end response, assuming your plot is accurate , i would increase the output LP filter by increasing the 120pF to 220pF or even 330pF ... (or more to taste)


Tweak #2

1. Grid to ground resistor higher  100m or 250m
2. Increase or decrease output coupling cap to taste to modify low end response

Hi Dan, I just finished up a 251 and it sounds very good, but I do hope to get a bit fuller low end. I am interested in the mods you have mentioned here, but as this is my first build I am still not able to understand the circuit and or schematic very well. I wonder if you could possibly let me know which resistors and caps could be changed by their part number..

decrease capsule voltage to 55V (reduce the 0.5MOhms to ground) R?
increase the 30Mohms grid resistor to 300Mohms R?
put a 100uF on the cathode instead of 22uF C?
output LP filter by increasing the 120pF to 220pF or even 330pF ... (or more to taste) C?
Grid to ground resistor higher  100m or 250m R?
Increase or decrease output coupling cap to taste to modify low end response C?

I do appreciate it very much, I so enjoyed the build and look forward to many more! Keep up the good work! I have also posted a pro tools session of my build next to a new Telefunken 251 if you are interested to hear!

Thanks

Andy

The documentation on the first page is very complete. There is enough there to figure out this info if you know tube circuitry. I'm only trying to help you help yourself here so I recommend reading up on how tubes work in a circuit and what each part of a valve does. I found this reading to be very informative. http://www.valvewizard.co.uk/Common_Gain_Stage.pdf
Try getting thru some of it and I feel those mods will start to make sense. Some of this is boring to get thru and some takes several times of reading to get for me. But it covers some stuff pretty well.

 

[andybaker28]

Ok , here is some tweaks you can do from original schemtics,

Tweak #1

If your capsule is a bit low end shy for your taste, try to decrease capsule voltage to 55V (reduce the 0.5MOhms to ground),  increase the 30Mohms grid resistor to 300Mohms and put a 100uF on the cathode instead of 22uF. U could increase the output coupling capacitor up to 3.3uF as well ....
with the high end response, assuming your plot is accurate , i would increase the output LP filter by increasing the 120pF to 220pF or even 330pF ... (or more to taste)


Tweak #2

1. Grid to ground resistor higher  100m or 250m
2. Increase or decrease output coupling cap to taste to modify low end response

Hi Dan, I just finished up a 251 and it sounds very good, but I do hope to get a bit fuller low end. I am interested in the mods you have mentioned here, but as this is my first build I am still not able to understand the circuit and or schematic very well. I wonder if you could possibly let me know which resistors and caps could be changed by their part number..

decrease capsule voltage to 55V (reduce the 0.5MOhms to ground) R?
increase the 30Mohms grid resistor to 300Mohms R?
put a 100uF on the cathode instead of 22uF C?
output LP filter by increasing the 120pF to 220pF or even 330pF ... (or more to taste) C?
Grid to ground resistor higher  100m or 250m R?
Increase or decrease output coupling cap to taste to modify low end response C?

I do appreciate it very much, I so enjoyed the build and look forward to many more! Keep up the good work! I have also posted a pro tools session of my build next to a new Telefunken 251 if you are interested to hear! I do have one question  still though I wonder about. When he says to lower the capsule  voltage to 55V, I am assuming that would be the B+ 120Voltage? If that is correct then would I also then need to change the 30M grid resistor to 300M at the same time? It seems that would be the case in my thinking, but I am not sure. I was out part hunting to day and a 300M resistor is really not easy to find! Thanks for any suggestions!

Andy

Thanks

Andy

The documentation on the first page is very complete. There is enough there to figure out this info if you know tube circuitry. I'm only trying to help you help yourself here so I recommend reading up on how tubes work in a circuit and what each part of a valve does. I found this reading to be very informative. http://www.valvewizard.co.uk/Common_Gain_Stage.pdf
Try getting thru some of it and I feel those mods will start to make sense. Some of this is boring to get thru and some takes several times of reading to get for me. But it covers some stuff pretty well.

Thanks so much for that Ding! I actually learned more from that article than I ever  dreamed I could. Lots of things did make perfect sense as I went through. I will continue to study it and for sure will get more comfortable with the mods in time!

 

[ding]

Seems one member had great results in getting better bass response by just changing the tantalum (C3) to 100mf. Enough that he didn't feel he needed to up (C1) the big output coupling cap on the main body. I would start there and see what that sounds like.

 

[andybaker28]

I finished my Elam 251 copy and had a chance to do a quick recording next to a new telefunken 251. I was pleased with the results but really hope to get a bit more low end out of mine. The Telefunken 251 really sounds great to me, love mixing vocals recorded through that mic. I will update the file  if I can get it sounding closer!

https://www.dropbox.com/s/rzenqzqn1ha7nyv/Copy%20of%20251%20mic%20test.zip?dl=0

 

[Tim Campbell]

What capsule are you using  Andy?

 

[andybaker28]

What capsule are you using  Andy?

Hey Tim, The mic I built was a complete kit from mic&mod in France. This was my first build so I wanted to get some experience with these before trying one on my own.  The capsule is the newest one that they send with the kit which is made in France from my understanding. I hope with a bit of circuit change I can warm it up a little on the bottom, but I doubt I can match the smooth high that is coming from the telefunken without a capsule change. I am considering to get a Beezneez capsule down the road, but first I will try some DIY ing to see what I might can get out of it...

 

[iprovlek]

I have my Elam for 5 years(mic parts capsule,RcA 12ay7 tube,Duka pcb)  for now,and I try lots of tubes and trannies on it!

I was waiting for right trannie from that !I tried Beyer,Pikatron,Lundahl and tried lots of differnte tubes!
I looked to the Oliver T14/1(listen the samples), then recently Banzai selling new Haufe T14/1,but I always been sceptic about it cause lots of guru people who knows and heard this mike told that new Haufe isnt the same like old one,even the T14/1 from Oliver TAB dont sound like original!

So recently I find the real Haufe T14/1 from '60-s on web!The price was funny....

I was solder this Haufe T14/1 in my Elam and I was totaly stunned!Totaly differente sound!

Always my Elam was need lots of gain, now no need for lots of gain! And sound amazing!

I think that is very important what to put in this microphone!

Now I start to  saving for Tim Campbell CT12 capsule,and maybe GE 6072 five star!But I satisified with RCA!


http://groupdiy.com/index.php?topic=47469.msg597086#msg597086

 

[JessJackson]

I have my Elam for 5 years(mic parts capsule,RcA 12ay7 tube,Duka pcb)  for now,and I try lots of tubes and trannies on it!

I was waiting for right trannie from that !I tried Beyer,Pikatron,Lundahl and tried lots of differnte tubes!
I looked to the Oliver T14/1(listen the samples), then recently Banzai selling new Haufe T14/1,but I always been sceptic about it cause lots of guru people who knows and heard this mike told that new Haufe isnt the same like old one,even the T14/1 from Oliver TAB dont sound like original!

So recently I find the real Haufe T14/1 from '60-s on web!The price was funny....

I was solder this Haufe T14/1 in my Elam and I was totaly stunned!Totaly differente sound!

Always my Elam was need lots of gain, now no need for lots of gain! And sound amazing!

I think that is very important what to put in this microphone!

Now I start to  saving for Tim Campbell CT12 capsule,and maybe GE 6072 five star!But I satisified with RCA!


http://groupdiy.com/index.php?topic=47469.msg597086#msg597086

Thats very interesting.

I know this too because in shoot out against vintage elam, my elams have always been lower -3 to -5 db and not due to voltage or capsule or tube.

I know its a pain in *** because you already soldered it in but can you please measure the resistance between the primary and secondary on the old haufe you acquired.

It would bevery interesting to see.

Jesse

 

[iprovlek]

Here is a picture of it!

I wont reassemble mic,it is pain in ***...

Wires:red,blue,red,blue-primary and two green-secoundary!

 

[iprovlek]

And  I get 5-6db more gain!

 

[lampas]

Banzai selling new Haufe T14/1,but I always been sceptic about it cause lots of guru people who knows and heard this mike told that new Haufe isnt the same like old one,even the T14/1 from Oliver TAB dont sound like original!
http://groupdiy.com/index.php?topic=47469.msg597086#msg597086

Did you try  Banzai T14/1 in your mic ?

 

[andybaker28]

Seems one member had great results in getting better bass response by just changing the tantalum (C3) to 100mf. Enough that he didn't feel he needed to up (C1) the big output coupling cap on the main body. I would start there and see what that sounds like.

I tried the switching of the tantalum to 100mf,  and also switched C2 to a 330pf but I did not feel much change in my case. I am really curious about lowering the voltage on the capsule but not quite sure how to do it. I am still new at this. I am not sure how  to lower the voltage to the capsule or if its the same as the B+ voltage, and then if I do reduce the voltage to 55v if also must switch the 30M resistor to 300M at the same time for it to work correctly. When I look at the schematic  I assume the capsule  voltage is the B+ 120, but I am not for sure!  :-[

I wonder if the low frequency that I am looking for is in the capsule, and if so then if anyone has compared some of the available ones and noticed any to have more low frequency?

Thanks for any suggestions!

Andy

 

[iprovlek]

Banzai selling new Haufe T14/1,but I always been sceptic about it cause lots of guru people who knows and heard this mike told that new Haufe isnt the same like old one,even the T14/1 from Oliver TAB dont sound like original!
http://groupdiy.com/index.php?topic=47469.msg597086#msg597086

Did you try  Banzai T14/1 in your mic ?

I didnt try Banzai Haufe T14/1 but I read Claus Hayne thread about NEW HAUFE T14/1,and he said that they are not like old ones which was used in Elam250!

 

[Banzai]

Check out reply #8 in this thread: http://repforums.prosoundweb.com/index.php/topic,36879.0.html

In short, Haufe has always built them the same way, for the same result. 

I didnt try Banzai Haufe T14/1 but I read Claus Hayne thread about NEW HAUFE T14/1,and he said that they are not like old ones which was used in Elam250!

 

[lampas]

The reason I ask is that I did also built two C12 microphones with T14 transfomers from AMI and found that they have a few dB lower output than my other mics. As T14 from AMI is 12:1 ratio and Haufe IS 11.5:1 maybe some expert would know if the ratio is
"guilty" for that few dB loss.... But I am satisfied with end result so the microphone will stay with T14 from AMI.

But I also have a "new" Haufe T14/1 and if you would test it in your microphone I would be glad to send it you as I and probably a few in the forum would like to hear opinion on new and old ones ... And I am not far from you ... (Ljubljana).

I also do not believe that between them are a big difference as on other thread I read that electrically are almost the same...
But I believe that there is a difference between T14 from AMI, CM2480 and Haufe T14/1.  CM 2480 is 10.5:1 ... Does this mean that it should be the "loudest" of the mentioned ones?

Regards.

 

[Banzai]

The AMI T14's lamination size and winding is definitely different (based on Hiller T14 instead of Haufe T14/1).