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

[NuSoundz]

Excellent, I will consider all those changes. 

I am using Chungers Elam style 3 dual layer basket.

What's the procedure to order the Haufe T14/1?

 

[ln76d]

First i would try to make voice test with headbasket and without it.
Here's pasted my advice from another topic:

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Do voice test - grab microphone (with whole body metal parts attached and option to take off headbasket) with one hand for the metal base, and with another hand keep headbasket (rather don't cover front of the capsule ). Compare between headbasket installed and without it. Without headbasket you can have problem with hum, so find the place in your listening room where there's lowest problem with hum (it's strongly dependent from your listening gear, amps preamps, psu, wall AC voltage etc.)
You can also try to cover a little the backside of the diaphragm (don't touch capsule) with a hand (second hand always keep metal pipe of the mic body). If you have variable HPF in your preamp, you can use it.
Difference which you should notice is mostly in the upper midrange and high frequency area.
Weak headbasket will usual overbright or make more nasal sounding microphone.
If you find that difference then after removing internal mesh should be better response, more neutral.
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If you will find difference in the range which you don't like then i would consider change of headbasket for single layer or removing internal layer in type 3.

Here's the link for T14/1:
https://groupdiy.com/index.php?topic=64243.0

 

[Phrazemaster]

Ok, here we go folks with the C12/ELAM shootout.  My CT12 equipped Chunger C12 vs CT12 equipped poctop ELAM.  Both mics were run into a vintage 1099 (1073 with fixed line gain) with no EQ or compression and straight to my SSL madi converters.  First is the C12, second is the ELAM.  I purposely mixed the backing track low fyi.  Results were what I expected... 

https://soundcloud.com/paradyne-studios/i-love-you-c12-then-elam-mic

Hey I just loved your sample! So much, where can I buy the whole song? I looked online but couldn't find it. Fab production, singing, playing. Great song! Thx!

 

[SparkleBear]

Hey y'all!

Just finished building my D-Elam251. So excited to have it all put together now!!! Its been a journey for sure... I am also now trying to bring up the bass response. I've upped the output cap to 3.3uf and looking into resistor changes and other tweaks as per these forum posts...

Im using the Beeskneez Body (beautiful job Ben and Veronica!), AMI t14, GE 5 star 6072a, TC12 capsule.

Anyway, I am wondering if I will have an issue (other than space) to use a higher voltage rated cathode bypass cap. I tried to find a 6.3v gold 100uf cap to replace the 22uf tantalum... I could only find the 10v rated ones. Could this cause me any issues granted I can fit it on the little tube PCB?

Also, I've seen mixed information of weather to set B+ to 110v or 120v... is there a definitive consensus on this? 

Further, if the voltage is set to 110v does this also mean that the 500k resistors are dividing the voltage for the capsule to be 55v? If I want more bass response would I lower the capsule voltage even more?? Tim Campbell recommended me to set only to 55v for optimum results.

Anyway, still experimenting with capacitor composition and values... But overall I am pleased... just need to get more bass!!

 

[midwayfair]

Also, I've seen mixed information of weather to set B+ to 110v or 120v... is there a definitive consensus on this? 

I just asked Tim about the polarization voltage and his reply was that "120V [is the maximum] but 110V sounds better." To my ears, he was right. However, the right answer is always "what sounds best to you (as long as you aren't damaging the parts)."

If you've increased the cathode capacitor AND the output capacitor to the values described, your circuit is already full range. At this point if there isn't enough low-end, it's probably not because you're losing it somewhere in the microphone's circuitry. Other factores you maybe can't easily do much about ... see some discussion in a recent thread about trying to get more bass from a figure 8 (which is fighting physics), maybe also something to do with the transformer output (I am murky on xfo resonance, so I won't speculate here), maybe something to do with the headbasket (though my understanding of this is that it mostly affects high end, and a really open headbasket like you're using should be more balanced).

This is what I personally would do if I knew a microphone was full range and I needed more bass. I am of course assuming that you aren't hearing something actually WRONG -- like a really thin sound, or something like that.

1) Easiest: put the mic in card and move it closer to the source to increase the proximity effect.
2) Next easiest: Add bass OR remove not-bass in post.

Neither of these involve altering a working microphone that otherwise sounds good, and if you have to do them every time you pull out the mic for heavy low-end stuff, then that's just part of learning your gear ... and maybe accepting that not every microphone is equally suited for every task.

You could also be hearing the high-end lift that's going to be normal for this type of microphone.

Someone else smarter than me might be along shortly to recommend more drastic measures.

 

[stribor1]

The Link to the schematics on the first page is not working anymore. Can someone please repost the docs?
Thanks,
J.

 

[SparkleBear]

The Link to the schematics on the first page is not working anymore. Can someone please repost the docs?
Thanks,
J.

Hey J,

I had the same problem and used the wayback machine to look for the images with success...

Here are two of the D-Elam251 schematics....

https://web.archive.org/web/20160915002210/https://dl.dropboxusercontent.com/u/43869772/Elam%20251/Elam%20251/Elam%20251%20Pictorial/Schemtic%20D-E251E.pdf

https://web.archive.org/web/20160915024854/https://cdn.groupbuilder.com/groupdiy/u/39511/58d1402a06461.pdf

If you want ANY of the broken links just go to:
https://archive.org/web/

Copy the link from the first page of the forum and paste the URL into the wayback machine and click the date link. I used this to look at some of the photos aswell as all the document files.

Cheers!

 

[Carnesd]

If you want ANY of the broken links just go to:
https://archive.org/web/

Copy the link from the first page of the forum and paste the URL into the wayback machine and click the date link. I used this to look at some of the photos aswell as all the document files.

Cheers!

Wow that is awesome!  How did I never hear about this!

 

[Tim Campbell]

HarmonyUnited I have PM'ed you.

 

[stribor1]

Hey J,

I had the same problem and used the wayback machine to look for the images with success...

Here are two of the D-Elam251 schematics....

https://web.archive.org/web/20160915002210/https://dl.dropboxusercontent.com/u/43869772/Elam%20251/Elam%20251/Elam%20251%20Pictorial/Schemtic%20D-E251E.pdf

https://web.archive.org/web/20160915024854/https://cdn.groupbuilder.com/groupdiy/u/39511/58d1402a06461.pdf

If you want ANY of the broken links just go to:
https://archive.org/web/

Copy the link from the first page of the forum and paste the URL into the wayback machine and click the date link. I used this to look at some of the photos aswell as all the document files.

Cheers!

Awsome! Thanks,
J.

 

[SparkleBear]

Hey everyone,
I am experiencing a higher than normal background white noise in my 251 build.  I put this mic up next to my TAB m49a (with ac701k) through the same pre amps at the same gain and noticed the white noise 251 was so much louder in comparison. The noise level is certainly making the mic unusable for most applications I would choose to use it for (vocals and acoustic finger style guitar). I've redone the whole high-Z circuit trying to clean it up. I bypassed the capsule and discovered the white noise is in the amplifier. I have a noise tested 6072a but swapped it out for other tubes with no change in the white noise. I changed the output cap and still no improvement... I'm thinking that somehow I damaged my styroflex caps while building the circuit.  Could this cause a higher than normal background white noise? I ordered another set of styroflex from Dany's site. Any other ideas from the gallery? Grounding problems don't usually cause white noise so I don't think its something like that... *shrug* Any guidance in the matter would be gratefully appreciated.

Cheers!

-Eric

 

[Delta Sigma]

Tube socket? Check that your pins are seating correctly - see if any of the mating pins in the socket are damaged or pushed to one side.

You could always replace the styroflex with any type of cap. Even a different but similar value. It might not sound good but it'll help in troubleshooting.

Don't rule out grounding.

What about your audio pair inside the power supply? Twisted? Short? Avoids filter caps?

 

[Gus]

I have a noise tested 6072a but swapped it out for other tubes with no change in the white noise.

How are the tubes noise tested? In a microphone circuit or in a lower input resistance audio circuit? This matters a lot.

What tubes NOS  or modern built brands are you using and how many have you tried? Tubes can have noise issues with tube microphone circuits

 

[SparkleBear]

Tube socket? Check that your pins are seating correctly - see if any of the mating pins in the socket are damaged or pushed to one side.

You could always replace the styroflex with any type of cap. Even a different but similar value. It might not sound good but it'll help in troubleshooting.

Don't rule out grounding.

What about your audio pair inside the power supply? Twisted? Short? Avoids filter caps?

I checked the audio pair in the power supply and shortened and twisted them and made sure they were clear of the filter caps. This did not solve the noise but definitely improved the aesthetic. 

Looks like the tube socket is doing okay.

How are the tubes noise tested? In a microphone circuit or in a lower input resistance audio circuit? This matters a lot.

What tubes NOS  or modern built brands are you using and how many have you tried? Tubes can have noise issues with tube microphone circuits

I am using a NOS GE 5-star 6072a sourced and tested by Brent Jesse of AudioTubes.com. I also tested a NOS GE 12av7 that David Pearlman sent me. Both offering the same white noise.

I noticed that there is a little melty spot on the C2 styroflex cap. Maybe this is causing the white noise??

Anyway, I am posting some photos of the circuit to maybe shine some light on the subject from y'alls wise eyes.

Thanks so much for the help!

-Eric

 

[Delta Sigma]

Did you "bypass" the capsule on the capsule side of the relays or the amp side?

Could be relay wiring. Does the same noise exist in all patterns? White noise louder or quieter in cardiod? Your signal will be louder in cardiod so generally your noise is quieter in cardiod.

 

[SparkleBear]

Did you "bypass" the capsule on the capsule side of the relays or the amp side?

Could be relay wiring. Does the same noise exist in all patterns? White noise louder or quieter in cardiod? Your signal will be louder in cardiod so generally your noise is quieter in cardiod.

And here are the photos of the circuit parts...

I bypassed the capsule at the capsule... just put 100pf caps in place of the capsule sides. Not sure how I can bypass the capsule at the amp side. The Noise is pretty much the same in all patterns with the capsule wired in. When i wired the capacitors in place though the noise was quieter in figure 8. which was weird...

Thanks again y'all!!

-Eric

 

[JessJackson]

And here are the photos of the circuit parts...

I bypassed the capsule at the capsule... just put 100pf caps in place of the capsule sides. Not sure how I can bypass the capsule at the amp side. The Noise is pretty much the same in all patterns with the capsule wired in. When i wired the capacitors in place though the noise was quieter in figure 8. which was weird...

Thanks again y'all!!

-Eric

theres my output cap

 

[Carnesd]

Hello Everyone,  I just got finished up with my D251 and alas my first mic that doesn't work correctly from the get go    Problem I'm having is only figure 8 pattern is working correctly,  cardoid doesn't work at all, and omni is very very low output. 

B+ and heater voltages are correct,  the capsule appears to be wired correctly and I feel like if it was the capsule wiring it wouldn't work in figure 8 as well.

I have relay voltage 6.2v to the omni and figure 8 pads on the mic when switching and no voltage in cardoid.  I can hear the relays clicking when switching between patterns.

I feel like I have an issue in my relay High Z ptp wiring but everything looks good,
Mainly wanted some confirmation that this sounds like an issue with the Hi z portion before I tear it apart and redoe it.

Thanks All!

 

[Tim Campbell]

Carnesd it sounds like you reversed your backplate connections , have a short between your backplates most likely within the capsule or your backplate connections are shorting against each other.

 

[Carnesd]

Thank you Tim,  I will go over the capsule and wiring again.