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

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Purplenoise

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As I am still waiting for the haufe t14 I used a cinemag for now just to test the mic. Changing the resistors to carbon film and the grid 30M to an old claro wirewound changes the sound significantly. Smoother and a touch dirtier but a lot closer to the vintage originals.
This time I prefer the tantalum 22uf that comes in the BOM...a more organic sound. I tried a nos axial Siemens tantalum and a sprague wet tantalum and although it sounded big and great it lacked a little of the midrange “reed-ness”.
The output cap is a 1uf 150v wet tantalum.
 

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tonycamp

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Hi guys, I still have NOT wired up the multi pin cable to run from the PSU to the mic, but can anyone tell me if getting 150vdc at the B+ terminal 1 on PSU board is correct? I’m figuring it must drop at the back of the mic jack but 30vdc seems a lot to me, I wanted to ask to be sure, thanx for sharing any info👍
 

Purplenoise

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tonycamp said:
Hi guys, I still have NOT wired up the multi pin cable to run from the PSU to the mic, but can anyone tell me if getting 150vdc at the B+ terminal 1 on PSU board is correct? I’m figuring it must drop at the back of the mic jack but 30vdc seems a lot to me, I wanted to ask to be sure, thanx for sharing any info👍
You’ll have to have the mic connected to get an accurate reading or use a resistor at the 7 pin xlr ( I believe that resistor is included in the bom...180k 2w if I am not mistaken). Then you just adjust the trimmer for B+ for 110/120v ( depending on capsule) The procedure is explained in the thread somewhere.
 

tonycamp

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Thanx man! It’s been so long since I started the project that I completely forgot about the 80k test load, I started reading into the thread but had to do some chores, when I saw your post I checked my project container and saw the pic below👍 Everything measures out perfect!
Thanx again 
Purplenoise said:
You’ll have to have the mic connected to get an accurate reading or use a resistor at the 7 pin xlr ( I believe that resistor is included in the bom...180k 2w if I am not mistaken). Then you just adjust the trimmer for B+ for 110/120v ( depending on capsule) The procedure is explained in the thread somewhere.
 

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Purplenoise

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A little update for those interested.
Tried a Black Gate standard for the cathode bypass ( 22uf) cap. I found a 47uf 16v and it sounds the best out of all the caps I tried in this position. Not that far off the Elna silmic but more detailed and dynamic. The silmic sounds a little veiled compared to the black gate. Since I am using the Tim Campbell capsule I uped the 100pf high cut cap to 250pf and it sounds fantastic with a great deal of 3D sense. I have those 2 caps in sockets so I can just swap in and out without desoldering.
Still waiting for the Haufe t14
 

Purplenoise

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So the build is complete. Installed a haufe t14 and it sounds great...mix ready almost.
After many component changes I ended up with:
-Tim Campbell capsule
-haufe t14
-black gate std cathode cap 47uf
-wet tantalum 1uf 150v
-nos ge6072 (60s)
-wirewound clarostat 29.7M grid resistor
-carbon film resistors
-250/300pf styrene high cut cap

I am really happy with this...for now haha
 

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Afzelius

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Hello everyone :) I'm having a weird problem, when mic is connected B+ doesn't drop at all. I noticed that there is 0V on R3 and R6. I just made a new Gotham cable and checked the connectivity between the pins on both sides and everything there looks right. No shorts between pins either. Any suggestions? :)
 

Frank00

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Hi guys,

Since the relay in the BOM (Panasonic DS2Y-S-DC6V) is out of stock at Mouser (at least here in Italy) and will be soon discontinued, I tried to find a replacement.

Here is the one I found:
https://www.mouser.it/ProductDetail/653-G6A-274P-DC6

From the specs, it looks like an exact replacement (even the housing dimensions) with the added bonus of having a 1Gohm insulation resistance (as opposed to 100Mohm of the BOM relay, which I know has been a topic of discussion before).

Do you think I could use it instead of the original one? I'd love if someone more experienced than me could share his opinion.

Thanks,
Francesco
 

Grandjoost

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Purplenoise said:
So the build is complete. Installed a haufe t14 and it sounds great...mix ready almost.
After many component changes I ended up with:
-Tim Campbell capsule
-haufe t14
-black gate std cathode cap 47uf
-wet tantalum 1uf 150v
-nos ge6072 (60s)
-wirewound clarostat 29.7M grid resistor
-carbon film resistors
-250/300pf styrene high cut cap

I am really happy with this...for now haha

Great work, man !
Mine is working since 2 years with no issues. Stock parts so far, but I really like. Just stared to swop output caps. MKP 3UF, CDE MPW 3,3uf and end up with a Russian PIO 3,3 uf. Wet tantalum in 1,75uf are on their way. High opener !
Perhaps I try your 30m resistor upgrade 😅. Experimented a bit with it at the beginning. Tried to move it up to 100m but I prefer the 30m there. The influences to sound was huge, so I may try your choice.

Setup:
- Tim Campell CT12
- AMI T14 (spare Haufe at Hand)
- K42-11 3,3UF 125V
- NOS 50s Honeywell 6072
 

Purplenoise

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Grandjoost said:
Great work, man !
Mine is working since 2 years with no issues. Stock parts so far, but I really like. Just stared to swop output caps. MKP 3UF, CDE MPW 3,3uf and end up with a Russian PIO 3,3 uf. Wet tantalum in 1,75uf are on their way. High opener !
Perhaps I try your 30m resistor upgrade 😅. Experimented a bit with it at the beginning. Tried to move it up to 100m but I prefer the 30m there. The influences to sound was huge, so I may try your choice.

Setup:
- Tim Campell CT12
- AMI T14 (spare Haufe at Hand)
- K42-11 3,3UF 125V
- NOS 50s Honeywell 6072
Nice...I tried PIO and Mp caps in this build and didn’t like them very much. The high end was kinda “glassy” with the Tim Campbell capsule. I much prefer wet tantalum...smooths the high end nicely. Also a wet tantalum cathode cap sounds quite nice too.
The haufe is a little lighter on the low end so you might wanna change the cathode cap to 47 or 100uf to compensate if you use it.
 

Grandjoost

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Purplenoise said:
Nice...I tried PIO and Mp caps in this build and didn’t like them very much. The high end was kinda “glassy” with the Tim Campbell capsule. I much prefer wet tantalum...smooths the high end nicely. Also a wet tantalum cathode cap sounds quite nice too.
The haufe is a little lighter on the low end so you might wanna change the cathode cap to 47 or 100uf to compensate if you use it.

Hey, I changed the high cut to 250pf Siemens sikantrop PIO and the output cap to 1,75 Ero wet tantalum. Like you said the glassy sound disappear. High ends smoothed out very well. Something phase related Happened in the low minds. There was always a slight hole especially compared to my vintage Tele U47(K47,VF14,BV8 MP). The wet tantalum really to the trick.
It is still brighter compared to the U47 as it should. Noise floor is up a few dB or so, perhaps the tube or the 250pf.
I Ordered two 1,75uf Tantalum but the other one was a 25uf🙄. As soon as the other one arrive, I will check back with caps in parallel.
And I will look for a wire wound 30m, perhaps I get a RFT here in Germany.

Setup so far:
Tim Campell CT12
APUTIS capsule holder
Honeywell 6072 50s
AMI T14
ERO ETAH1 1,75uf
250pf Siemens Sikantrop
 

Purplenoise

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Grandjoost said:
Hey, I changed the high cut to 250pf Siemens sikantrop PIO and the output cap to 1,75 Ero wet tantalum. Like you said the glassy sound disappear. High ends smoothed out very well. Something phase related Happened in the low minds. There was always a slight hole especially compared to my vintage Tele U47(K47,VF14,BV8 MP). The wet tantalum really to the trick.
It is still brighter compared to the U47 as it should. Noise floor is up a few dB or so, perhaps the tube or the 250pf.
I Ordered two 1,75uf Tantalum but the other one was a 25uf🙄. As soon as the other one arrive, I will check back with caps in parallel.
And I will look for a wire wound 30m, perhaps I get a RFT here in Germany.

Setup so far:
Tim Campell CT12
APUTIS capsule holder
Honeywell 6072 50s
AMI T14
ERO ETAH1 1,75uf
250pf Siemens Sikantrop
Great, with the high cut don’t be afraid to go up to even 500pf with the Tim Campbell capsule. Still sounds plenty bright. If you have more noise ( and it is not the tube) check the wet tantalums for leakage...
Also as far as the wirewound 30M listen carefully for RF interference...some pick up RF.
 

ghiatorino

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Can anybody confirm the mic sensitivity drops around 3db from Cardioid to Omni and around 6dB from Cardioid to Fig.8?
 

Grandjoost

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Purplenoise said:
Great, with the high cut don’t be afraid to go up to even 500pf with the Tim Campbell capsule. Still sounds plenty bright. If you have more noise ( and it is not the tube) check the wet tantalums for leakage...
Also as far as the wirewound 30M listen carefully for RF interference...some pick up RF.
The second 1,75uf wet tan arrived and Checked it in parallel and serial. parallel does it for me, so I am at 3,36uf now. Bass to deep mid balance fits really well and comparable to my vintage U47.
With 1,75uf or in serial the deep mids sounds hollow and there was a unnatural bass build up around 80 HZ.
Noise was from the tube, moved it a little and the noise was gone.
Found no matching wirewound so far, but I will keep my eyes open.
Cheers
JST
 

Purplenoise

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Grandjoost said:
The second 1,75uf wet tan arrived and Checked it in parallel and serial. parallel does it for me, so I am at 3,36uf now. Bass to deep mid balance fits really well and comparable to my vintage U47.
With 1,75uf or in serial the deep mids sounds hollow and there was a unnatural bass build up around 80 HZ.
Noise was from the tube, moved it a little and the noise was gone.
Found no matching wirewound so far, but I will keep my eyes open.
Cheers
JST
Nice. Your u47 has an original vf14? All original parts?
 

Grandjoost

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Purplenoise said:
Nice. Your u47 has an original vf14? All original parts?
Yes Orginal late 50s Telefunken, K47,vf14,bv8, Bosch MPs and Orginal Styroflex caps. Just one resistor is not Orginal.
 

Purplenoise

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Grandjoost said:
Yes Orginal late 50s Telefunken, K47,vf14,bv8, Bosch MPs and Orginal Styroflex caps. Just one resistor is not Orginal.
Awesome. As I am fine tuning my clone would you mind if at some point I asked you for some sound samples? If it’s not too much work, something easy.
 

Grandjoost

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Purplenoise said:
Awesome. As I am fine tuning my clone would you mind if at some point I asked you for some sound samples? If it’s not too much work, something easy.
Shure, no Problem. But will that help ? Different source & room  make it nearly impossible to fine tune.
Where you from ?
 

Purplenoise

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Grandjoost said:
Shure, no Problem. But will that help ? Different source & room  make it nearly impossible to fine tune.
Where you from ?
I live in New York. Yes it’s true, just want to hear reach of low frequency and saturation characteristics. Very general...mostly the vibe. I had an original here but didn’t record any samples and now I don’t have access haha.
 

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