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

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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



Tweak #3
Hi there, I actually did buy the resistors but not yet installed them, in the meantime though I did switch the .22 uf Tantalum to a 100uf Tantalum and did not hear a change. Then later switched the 100uf Tantalum to a 100uf gold panasonic electrolytic and man the bottom really came up then. I did not have much time to test it on acoustic guitar yet, but the low on my vocal was much more without being muddy or too much. I will try the resistor change to lower the voltage down to 55V soon, I was sort of wanting to see if what I had calculated was correct first. I guess it won't damage  anything to try! I will keep you posted as I proceed!
Thanks again
 
poctop said:
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
Click to expand...

Thanks :)

But the pcb is 1:1 based on the original schematic or did you take any freedom in changing parts / signal structures?
 
atticmike said:
poctop said:
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
Click to expand...

Thanks :)

The Circuit is exact replica of Ela-M251 but you can go ahead and change the component value up to your taste  ;)
the Silkscreen Value of the pcb are the published Value of the Elam251 Schematic,  But feel free to expirement.
this is DiY afterall  :)

Best,
Dan,







But the pcb is 1:1 based on the original schematic or did you take any freedom in changing parts / signal structures?
Click to expand...
 
poctop said:
atticmike said:
poctop said:
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
Click to expand...

Thanks :)

The Circuit is exact replica of Ela-M251 but you can go ahead and change the component value up to your taste  ;)
the Silkscreen Value of the pcb are the published Value of the Elam251 Schematic,  But feel free to expirement.
this is DiY afterall  :)

Best,
Dan,







But the pcb is 1:1 based on the original schematic or did you take any freedom in changing parts / signal structures?
Click to expand...
Click to expand...

Thanks, that's what I wanted to know :) So now, I don't have to compare it with the original and can already make DIY changes to shift the sound to my liking. 
 
atticmike said:
poctop said:
atticmike said:
poctop said:
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
Click to expand...

Thanks :)

The Circuit is exact replica of Ela-M251 but you can go ahead and change the component value up to your taste  ;)
the Silkscreen Value of the pcb are the published Value of the Elam251 Schematic,  But feel free to expirement.
this is DiY afterall  :)

Best,
Dan,







But the pcb is 1:1 based on the original schematic or did you take any freedom in changing parts / signal structures?
Click to expand...
Click to expand...

Thanks, that's what I wanted to know :) So now, I don't have to compare it with the original and can already make DIY changes to shift the sound to my liking.
Click to expand...

That is the ultimate Goal , of microphone Building :)
 
atticmike said:
poctop said:
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
Click to expand...

Thanks :)

But the pcb is 1:1 based on the original schematic or did you take any freedom in changing parts / signal structures?
Click to expand...
Dany being the very stand up chap that he is, is being very helpful and diplomatic.
The Schematic to both are in the first post. How about you take a look to see if they are the same? ;)
 
duantro said:
Dany being the very stand up chap that he is, is being very helpful and diplomatic.
The Schematic to both are in the first post. How about you take a look to see if they are the same? ;)
Click to expand...
  Well put.  I'll add that without using original transformers, capsule, caps, etc, we aren't building an exact sounding replica so don't get too hung up on the minutia.  I've found that, when using modern components, sometimes deviating a little from the original actually gets you closer to that original sound, depending if the components you're using are giving you a brighter/darker/etc sound.  And, I know this is blasphemy, but sometimes you can even make adjustments that sound better to your ears than original spec.  I've stopped thinking of original tone as being the ultimate goal and have found greater success in taking a piece of gear I like and building it to sound exactly how I (or my customer) want it to sound.
 
Bowie said:
duantro said:
Dany being the very stand up chap that he is, is being very helpful and diplomatic.
The Schematic to both are in the first post. How about you take a look to see if they are the same? ;)
Click to expand...
  Well put.  I'll add that without using original transformers, capsule, caps, etc, we aren't building an exact sounding replica so don't get too hung up on the minutia.  I've found that, when using modern components, sometimes deviating a little from the original actually gets you closer to that original sound, depending if the components you're using are giving you a brighter/darker/etc sound.  And, I know this is blasphemy, but sometimes you can even make adjustments that sound better to your ears than original spec.  I've stopped thinking of original tone as being the ultimate goal and have found greater success in taking a piece of gear I like and building it to sound exactly how I (or my customer) want it to sound.
Click to expand...

Agreed but having the low end off is more defective than comparable in taste, that's why I've mentioned this to Dan, cause he's the man.

Also, is there a kit for the PSU anywhere for sale? Like the chassis, parts et cetera? Or at least just the chassis?
 
Someone around here selling beeznees bodies / similar high quality bodies for this project and chassis' for the psu?
 
Can this be used for the build?:

http://store.t-funk.com/p/m-950s-dual-tube-microphone-power-supply-ela-m-251?pp=24

Fine price for a dual PSU.

Update:  Damn it, no switch for the positions

How about this one?:

t.JPG
 
Seems like a waste of money for a diy-er since you can make a better one for a lot less.  As I posted above, Dan D has a good case for this.

atticmike said:
Can this be used for the build?:

http://store.t-funk.com/p/m-950s-dual-tube-microphone-power-supply-ela-m-251?pp=24

Fine price for a dual PSU.
Click to expand...
 
Speaking of the Beesneez 251 bodies, does anyone know if a swivel mount that could be used with these? The Beesneez mic body is so heavy, I'm afraid it will fall out of the shock mount if put upside down.
 
Just finished my ELA !
I had a little problem with my heater voltage.  As I'm using a different toroid, (200V and 6,3V) I replaced R7 and R8 on the psu with wire. Then I got 6,2 V, which seemed good enough.
But in Fig8 and Omni I had a hum, which disappeared, when I decreased H+ to 5.95V
Mic sounds fine, but has a pretty high noise floor...

Would you recommend to bring the heater up to 6.3V ?
 
Hi there, doing my first DIY mic and chose the 251 kit from Mic and Mod. I am not so good with schematics and am looking for a clear explanation from the 7pin connector to the PCB on the mic. So far I am not sure how to wire them. Can someone let me know the pin out on the connector goes to where on the PCB.

Thanks much!

Andy
 
andybaker28 said:
Hi there, doing my first DIY mic and chose the 251 kit from Mic and Mod. I am not so good with schematics and am looking for a clear explanation from the 7pin connector to the PCB on the mic. So far I am not sure how to wire them. Can someone let me know the pin out on the connector goes to where on the PCB.
Thanks much!

Andy
Click to expand...

Hi, have you looked at the mic diagram file at page 1?  Your info should be there.
 

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