Apex 460 mod with some Telefunken ELA M 251 influences

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

saxmonster

Well-known member
Joined
Jan 3, 2012
Messages
534
My new project will be a build of the Telefunken ELA M 251 out of my Apex 460.  I would like all of the components to be as close to the factory specs as can be.  I know it will not be an actual 251 but clones are a lot of fun make and understand.

I want this to be an all in one resource to all the links I have found online and the schematics.

From looking and reading on this forum and on the net i have compiled a list of what I need to swap and change so far.  Please make suggestions as to what i might be doing wrong or any concerns you might have. 

My Apex 460                       Swap for an Elam 251


Capsule Chinese                   Tim's CT-12 or Peluso CEK12 or PK47

TUBE 12AX7B                       GE 6072A 5 star NOS or Ecc801s

Transf Stock Transf               BV11

PSU Original Zener diodes         Change Z5 to a 61v Zener from a 72 volt zener

Circuit Cathode Follower           Cathode Follower CCDA (constant current draw amplifier)

R2 2w 100k                       3w 100k
R3 1/2w 270k                     1/2w 500k
R4 1/2w 270k                     1/2w 500k
R6 200M                         7w 200M
R7 1/2w 2.7K                     1/2w 1.8k
R9 51M                           1w 250M Use Ohmite
R10  1KM / 1G                         1w 250M Use Ohmite


C1 1uf/450v                       Don't have to swap already Electrolytic
C2 1uf/450v                       Don't have to swap already Electrolytic
C4 1000p/630v                   1000pf/160v Polystyrene
C5 .022uf/400v                   4700pf/160v Polystyrene
C6 100uf/25v                     Remove
C7 0.1uf/63v                       Remove
C8 1uf/450v electrolytic             1uf/250v Metal Film (solen Fast)
C9      0.1uf/63v                              Remove
C10    0.1uf/63v                              Remove
C11 NONE                              100pf/500v Mica Silver

Links That I am finding the info from,

http://www.groupdiy.com/index.php?topic=47764.0
http://www.groupdiy.com/index.php?topic=48211.0
http://recordinghacks.com/microphones/Telefunken/ElaM-251
http://www.groupdiy.com/index.php?topic=31837.0
http://www.treblebooster.com/m251e/telefunken_ela_m251e_circuit.htm
http://recordinghacks.com/2010/02/14/the-advanced-audio-cm12-mod/
http://www.saturn-sound.com/Curio's/elam_microphones.htm
http://www.gearslutz.com/board/low-end-theory/599895-help-w-diy-telefunken-ela-m-250-251-a.html
http://www.coutant.org/akgc12/index.html
http://www.foxaudioresearch.ca/TheM251.htm
http://www.foxaudioresearch.ca/The460secret.htm
http://homerecording.com/bbs/equipment-forums/microphones/apex-460-a-180723/
http://messageboard.tapeop.com/viewtopic.php?p=536568
http://messageboard.tapeop.com/viewtopic.php?p=536568
http://www.soundonsound.com/sos/may10/articles/peluso22251.htm
http://www.morphproductions.com/apex460transformermod.htm


Schematics

http://www.groupdiy.com/index.php?action=dlattach;topic=47764.0;attach=11980;image
http://www.coutant.org/akgc12/elam250_2.jpg
http://www.treblebooster.com/m251e/m251e.pdf
http://www.coutant.org/akgc12/c12schem.gif
http://www.coutant.org/akgc12/akg-c12.pdf
http://www.gearslutz.com/board/attachments/geekslutz-forum/111879d1235602544-apex-460-mod-u47-apex-460-mods.pdf


Capsule

http://www.timcampbell.dk/index2b.htm
http://www.pelusomicrophonelab.com/parts/Capsules.html

Transformer

http://www.tab-funkenwerk.com/id76.html
http://cinemag.biz/mic_output/mic_output.html



Am I missing anything else?  Pictures will follow for each swap I do, caps, resistors, etc.

Thanks so much
-Scott



 
It would be good to see the schematics you're referring to. In the  ELA M schematic I have B+ is 110V, not 120V. And there's no 250M or 200M resistors. Polarization resistor are 8M and grid to ground 30M. And plate to grid cap (C8?) is  3.2uF. Anyways, I wouldn't use these values but make the mic 'better', in example leave the stock Apex high value resistors there. And not much use changing hte voltage divider (R3, R4). And NOS 6072a's are very expensive. I'd try an other tube. Tim's capsule is the way to go BTW!

 
e.eoelberg.

ecc801s are the europe tube version that telefunken puts into the non export 251's right?  Where could i order thess at for us people?

Also it looks like Tim's capsule is $355.25 usd plus shipping and I guess I would have to pay for duties too.  Such decisions.


Pasarski,

I was going off someone's hand draw schematic (posted them above with an update) but I will look into this further and what tubes would you recommend and where would you purchase them from?  Trying to get as many ideas as possible. love this stuff!!!!!

Thanks
-Scott
 
saxmonster said:
ecc801s are the europe tube version that telefunken puts into the non export 251's right?  Where could i order thess at for us people?

The european version got a Telefunken AC701 tube.
 
E cc801s is a long life 12 at 7... It sounds very good in an elam  circuit. Whatever you'll use the capsule and working with clean fingers will make the biggest difference in sound. Even drilling a wire with greasy fingers might make your mic more noisy than a bad tube.
 
Hi saxmonster, thanks for the link parade! I am really interested in this topic and I will start with my own ELA 251 clone soon.

I have heard e.oelbergs clone based on Tim's capsule and a Telefunken Ecc801 via a V72 and I was really impressed. I would give an arm and a leg for this combination! (I bought myself a pair of V72s after that session. Next money will go out for two Tim Campbell capsules...;-)

Now I am searching for a good pair of bodys for my clones...


 
Nicholas,

I will look into getting an E cc801 tube then.  I have started to read about them and like what I am hearing.  I think I am leaning toward Tim's capsule too I will just have to save a bit more.  Also can you repost some of your pics from your thread.  I was there and didn't see any.  You can have them on your thread and I will cross link them.  Also what schematic are you using can you upload that too.

Soderstrom,
I will be updating the link and other stuff during this project so I hope it becomes a great resource for people doing this.  One place to find everything, hahahahahah.  I will be using this mic through the eeezzz 1073 clone  found on here.  Many of the sax players I enjoy listening to use this combination of a 1073 and a 251.  Hopefully I will be pretty close, hahahahahh. 


Anyone know of a good reliable place to buy these E cc801 tubes from in the USA or any where I guess?

I have never delt with tubes before as I am not a guitar player or had a microphone with them.

Thanks guys.

 
I have 2 Peluso Transfo Here for CK12 Style, they  are called the T14-1, they sell for 125.00 each i am letting them go for 70.00

this would fit this project i believe,

PM me if something,

Dan,
 
Hi Saxmonster,

This guy has a lot of badass NOS tubes. I emailed him about some other flavors. He replied to me this morning and said the stock listed on the website is current.

This link will take you straight to his 12AT7 page

http://www.audiotubes.com/12at7.htm

Good luck with your 251,
DAve

 
Hi Dave,
Thanks for the heads up. I will definitely check him out.  Is 12AT7 the tube type / style that fits these mics?  All of these numbers start to sound the same.  Just don't know what to go with I see that the telefunkens are shipping with the 6072 tube but the e cc801 are suppose to be good to.



Why are photos of the elam guts showing different resistors and caps?  Is it based on stock that they have on hand?

look here at the bottom of page.

http://www.coutant.org/akgc12/

which is different from this photo

http://costaq.com/images/images_big/Telefunken/ElaM251E_2.jpg

It seems the more I did into this the more confused I get hahahah.

 
Sax,

The 12AT7 and ECC801s is in the same "family". Brent groups his tubes like that on his site. If you go to the link and scroll down past all his concise tube family info you get to the white table portion where he lists the actual tube numbers, info and pricing. He has 2 Telefunken ECC801s. They are not cheap, but those tubes are pretty rare.

One immediate difference I see in the 2 photos is the use of PIO caps and big 'styrenes in the first. Maybe the 2nd photo's mic uses more "modern" components?

Dave
 
I think I might get a Ge 6072a 5 star nos for the time being as he is out of stock on the Ecc801s.  He just has a pair and I don't think he will break that up.  I will email him and tell him that I am interested in an Ecc801 incase he comes across one. 


I can still use a plate circuit for the 6072a right?  After all that is what todays version of the 251 has installed.


 
saxmonster said:
I think I might get a Ge 6072a 5 star nos for the time being as he is out of stock on the Ecc801s.  He just has a pair and I don't think he will break that up.  I will email him and tell him that I am interested in an Ecc801 incase he comes across one. 


I can still use a plate circuit for the 6072a right?  After all that is what todays version of the 251 has installed.

I'm not sure about the Cinemag transformer but with the T14 yes for sure. And 6072a is the tube used also in the original 251E. I see ECC801's are expensive too. If you're ready to invest that much for the tube go for the 6072a 5 stars!

I made a very nice sounding mic with 5670 tube , Lundahll LL1935 trafo and CT12 capsule. Still need to weed out a super quiet 5670, I have bunch of different brands, but every one I've tried this far is acceptable for not-so-super-quiet rooms (more noise from the room than the mic). I've had also good luck with couple of basic NOS 12AT7's I've used in china cathode follower mics.
 
From the website:

ECC801S (12AT7 premium tube) Siemens made in Germany        $140.00        2 (in stock)

Looks like there are some singles if you're willing to pay for them! ;)

Dave
 
He has the ge 5 star listed for $69  compared to an Ecc801 for $190. 

I think maybe i will get a cheap grooves tube 6072 for $39 just to get the mic up and working and then replace with an older better sounding vintage tube.  I don't want $200 to go down the drain like that.

Thanks guys
-Scott
 
wave said:
From the website:

ECC801S (12AT7 premium tube) Siemens made in Germany        $140.00        2 (in stock)

Looks like there are some singles if you're willing to pay for them! ;)

Dave

Does it matter telefunken or siemens?  I thought i would go for the telefunken?
 
saxmonster said:
wave said:
From the website:

ECC801S (12AT7 premium tube) Siemens made in Germany        $140.00        2 (in stock)

Looks like there are some singles if you're willing to pay for them! ;)

Dave

Does it matter telefunken or siemens?  I thought i would go for the telefunken?

Scott,
You should call Brent and talk to him about it. He will be more than willing to give you some "sound" advice (doom doom, crash)

Dave
 
saxmonster said:
He has the ge 5 star listed for $69  compared to an Ecc801 for $190. 

I think maybe i will get a cheap grooves tube 6072 for $39 just to get the mic up and working and then replace with an older better sounding vintage tube.  I don't want $200 to go down the drain like that.

then why put $39 down it when you already have the stock 12ax7?  you can certainly be "up and working" with an ax7 in place of an at7/801/6072.  not that i expect the 6072 to be a total slouch and necessarily need replacing... but if you're gonna pull it in favor of an upgrade anyhow you may as well just work with what you have.
 
grantlack said:
saxmonster said:
He has the ge 5 star listed for $69  compared to an Ecc801 for $190. 

I think maybe i will get a cheap grooves tube 6072 for $39 just to get the mic up and working and then replace with an older better sounding vintage tube.  I don't want $200 to go down the drain like that.

then why put $39 down it when you already have the stock 12ax7?  you can certainly be "up and working" with an ax7 in place of an at7/801/6072.  not that i expect the 6072 to be a total slouch and necessarily need replacing... but if you're gonna pull it in favor of an upgrade anyhow you may as well just work with what you have.


Your absolutely right!!!!  I am a total noob at this and thought for some reason that the tube I have now would not work with the new plate circuit or for what ever reason.  I am just an idiot.  I have so much more reading and learning to do.  How many different tube "families" are there for microphones?  Do tubes only fit in certain adapters?  Say if i have my clone with an 12ax7 would i be able to fit a smaller guitar tube in it?  Are the pins spread out different from tube "family" to "family".  I just don't want this project to go up in smoke, hahahahah.  Love that movie.

-Scott

 

Latest posts

Back
Top