Re: Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)
« Reply #720 on: December 14, 2020, 01:56:42 PM »
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.
« Last Edit: December 14, 2020, 02:05:22 PM by Purplenoise »


tonycamp

Re: Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)
« Reply #721 on: December 22, 2020, 05:38:58 PM »
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👍

Re: Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)
« Reply #722 on: December 22, 2020, 07:55:48 PM »
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

Re: Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)
« Reply #723 on: December 22, 2020, 10:45:26 PM »
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 
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.

Re: Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)
« Reply #724 on: December 24, 2020, 02:31:19 PM »
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

Re: Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)
« Reply #725 on: December 30, 2020, 03:21:31 PM »
Hey! I just finished my 251 build but I'm having a weird problem. I get the correct voltages on B+ and H+ when the mic is not connected but when I connect it B+ drops to 0. H+ stands still though. The tube does not really light up when the mic is connected. Any suggestions? :)

duantro

Re: Telefunken ELA M 251 Clone Tube Microphone Build Thread (D-Ela M 251E)
« Reply #726 on: December 31, 2020, 11:45:14 AM »
Check for shorts along your B+ path in the mic/ cable