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

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LevinGuitar

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Will this random chinese mic (apex460) mod would be close to a Elam 251? What change would make it closer or just better sounding?
I would like to use Tim capsule and Moby T14. Any suggestion is welcome :)
 

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doqmemory

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Will this random chinese mic (apex460) mod would be close to a Elam 251? What change would make it closer or just better sounding?
I would like to use Tim capsule and Moby T14. Any suggestion is welcome :)
Yes, it is similar to the Matador ELA M251 that Chunger sells, detailed in ELA M251 Inspired Microphone - Build Thread

You will also need to mod or replace the power supply, as the stock B+ will be too high. If you get the board from Chunger, it also includes the PSU PCB.

The Apex 460 headbasket should also be replaced. Chunger sells an appropriate one, but other sources are Microphone Parts (C12 style, but better than stock) and Advanced Audio.

Dan's ELA M 251 clone (that this thread is for), is a similar circuit, but uses relays to switch the pattern, allowing more headroom. It is more challenging to build, but is closer to the original circuit.

I have one of each and the sound is quite similar. The only feature that I miss in Dan's PCB set is the ability to easily switch sides on the tube.
 

LevinGuitar

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Thank you!
Yes, I know the headbasket shape and mesh are important, I have different mics to try.

I was wondering if I have to lower resistor values, or if the extra 1000pf cap in the sound path in this circuit would downgrade the sound a lot. But guess should follow Matador's schematic (without relays).
 
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Tahoebrian5

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Hi all, I just ordered the boards for this project and am in progress sourcing the rest of the parts. I only made it about 1/2 through this long thread but am having trouble following along some of the discussion because the layouts and schematic links in post #1 are broken.

I’ve got a few questions, hope you guys don't mind if I put them here (and I will finish reading the rest of the thread over the next couple days)

Firstly, can someone help me with a new link or message for the schems and layouts pretty please!

Is there an updated source now for the 3.3 mF cap that is out of production on the mouser bom?

Where can I order a Tim Campbell capsule?

I am planning to run the Haufe Xformer So far. Are there any sources in the US? The Don website is looking like about a month lead time. I would be interested in any discussion about pros cons of other transformers also. I love the current Tfunk USA tone but wondering if I could get the same result with a cheaper transformer and tune the circuit for the low end as I’ve read a bit about here by changing component values.

Lastly, I’m looking at the Apex mic for a body donor. Any reason not to use the Apex power supply case as well for the PS build? Any other mic bodies or PS cases I should consider? The beesneez looks great but is an extra $500!

Thanks a bunch and looking like a fun build!
 

doqmemory

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Hi all, I just ordered the boards for this project and am in progress sourcing the rest of the parts. I only made it about 1/2 through this long thread but am having trouble following along some of the discussion because the layouts and schematic links in post #1 are broken.

I’ve got a few questions, hope you guys don't mind if I put them here (and I will finish reading the rest of the thread over the next couple days)

Firstly, can someone help me with a new link or message for the schems and layouts pretty please!

Is there an updated source now for the 3.3 mF cap that is out of production on the mouser bom?

Where can I order a Tim Campbell capsule?

I am planning to run the Haufe Xformer So far. Are there any sources in the US? The Don website is looking like about a month lead time. I would be interested in any discussion about pros cons of other transformers also. I love the current Tfunk USA tone but wondering if I could get the same result with a cheaper transformer and tune the circuit for the low end as I’ve read a bit about here by changing component values.

Lastly, I’m looking at the Apex mic for a body donor. Any reason not to use the Apex power supply case as well for the PS build? Any other mic bodies or PS cases I should consider? The beesneez looks great but is an extra $500!

Thanks a bunch and looking like a fun build!
All of the pdf links on the first page of the thread work for me. I used them extensively in the past several weeks for my build. You may need to highlight them manually and select "Go to ..." from the context menu (if Chrome).

An alternate Cornel Dublilier cap is at Mouser. You can find 3.3 MFD capacitors or eBay and Amazon. The vintage PIO's are pretty much eBay only.

I suppose you order the CT12 capsule by PM to Tim or the email on his website. I've been trying to get some for my 2 ElaM251 clones. The Heiserman HK12 is quite nice, although mine is in a C12 clone. The BeezNeez CK12 looks lovely, too.

I've used the CM-13113 in the ones I've built, since Chunger has them. You can order an accurate reproduction from Moby by PM. The AMI T14 would work well, of course. I have a 3U Audio GZT-12 ordered, but do not have it yet to compare.

The Apex 460 style of mic body and PSU is exactly what Dan's boards are for. The PCB fits right into the Apex 460 PSU case, using the same transformer. You should definitely replace the headbasket. The Chunger one is great, but Advanced Audio sells similar ones, I think.
 

Tim Campbell

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I have and so have many of my clients. I realize that I am too busy these days to be able to fill everyone's orders. I would highly recommend the Haun MBHO capsule or the Josephson capsule.
 
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wave

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I am planning to run the Haufe Xformer So far. Are there any sources in the US? The Don website is looking like about a month lead time. I would be interested in any discussion about pros cons of other transformers also. I love the current Tfunk USA tone but wondering if I could get the same result with a cheaper transformer and tune the circuit for the low end as I’ve read a bit about here by changing component values.
In My experience, the small L laminations and the high primary DCR coupled with the low inductance give the real T14/1 a special sound that other transformers - no matter how you swap the components around - won't replicate.
 

Purplenoise

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I have and so have many of my clients. I realize that I am too busy these days to be able to fill everyone's orders. I would highly recommend the Haun MBHO capsule or the Josephson capsule.
I do have your ct12 and it’s truly a stunning capsule. I don’t believe haun or josephson sell direct though…at least not single pieces.
 

Tahoebrian5

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Thank you for the info and links.

Tim I sent an email via the link on your site And hope to get one from you but completely understand if they are not available. I’ll take a look at your other recommendations as well.

@wave , regarding the Haufe transformer, are you referring to the current production item, or is this a vintage transformer you are referring to? To add further confusion I have read somewhere that there is an alternative current production Haufe that has a low freq boost that the USA Tfunk Ela uses. I am probably confused though!

i ordered an AMI but may look after a Haufe as well.
 

Tahoebrian5

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Can some of you share your thoughts on using a 12AT7 tube in lieu of the 6072? Would the tone be in the ballpark if the bias point was accounted for?
 

gyraf

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yes, in general I find that good NOS ECC81 (your 12AT7) most often outperforms new-production "6072" branded tubes for microphone frontend use.

I do NOT know how bad new-production ECC81's are though..
 

doqmemory

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Change anode resistor from 100k to 47/50k,PSU needs more current also with ecc81,reduce the dropping resistor values after the diodes
Those are the changes that I made for 12AT7, 47K cathode resistor (instead of 100K) and 33K for the two PSU resistors after the diodes for B+ (instead of 68K for Matador PSU, 75K for Dany PSU).
 
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