KM84 project build

[kingkorg]

I built four km84 clones in mxl bodies with 3u capsules.  I found the performance to be basically indistinguishable from my real km84.  The below video is my comparison -
https://youtu.be/nVJxx7YM-6I

One can't argue with that. Phenomenal!

 

[craigmorris74]

I built four km84 clones in mxl bodies with 3u capsules.  I found the performance to be basically indistinguishable from my real km84.  The below video is my comparison -
https://youtu.be/nVJxx7YM-6I

Those do sound great!  What transformer is in your mics?

 

[Leslie 123]

The Warm capsule looks close from the front and rear.  I don't know who makes it, and haven't seen one dissected.

Again, it seems 3U audio, it's long needle type like neumann kk84 but don't fit neumann nor mxl. I tried WA84 in frends shop, very nice mic, my ears prefers it over KM184 and Oktava 012.
Also i found this detailed test so anybody interested can listen https://www.amazona.de/test-warm-audio-wa-84-stereo-set-kleinmembranmikrofon/

 

[Leslie 123]

Those do sound great!  What transformer is in your mics?

Rob stated in thread with clips he used cinemag trafo.
Still i'm curious if new 3u audio capsule fits MXL603s body. Guosheng is not sure, it fits his Warbler line.... but older 3U audio capsule looks as same as micparts one. If someone here can confirm that new capsule can fit mxl body or with minor adjustments that will help a lot
Rob?

 

[craigmorris74]

Rob stated in thread with clips he used cinemag trafo.
Still i'm curious if new 3u audio capsule fits MXL603s body. Guosheng is not sure, it fits his Warbler line.... but older 3U audio capsule looks as same as micparts one. If someone here can confirm that new capsule can fit mxl body or with minor adjustments that will help a lot
Rob?

Yes, I just tested the 127 C Flat capsule on my 84 copy from the project here, and its the same threads as the MXL.

 

[Khron]

How dissimilar is that thread, from something like a Rode NT5 / NT55, I wonder?

 

[Leslie 123]

Yes, I just tested the 127 C Flat capsule on my 84 copy from the project here, and its the same threads as the MXL.

Thanks man!
I just ordered two flat C capsules 

 

[Leslie 123]

Capsules arrived,  here is test
Schweppes - 3UAudio capsule, Schoeps circuit
Leslie 84 - 3UAudio capsule, Neumann km84 circuit
Oktava Mk-012

Guitar
https://www.youtube.com/watch?v=m-6fQjGiRMo

Mandolin
https://www.youtube.com/watch?v=IcrSdZmqIyg

 

[craigmorris74]

Capsules arrived,  here is test
Schweppes - 3UAudio capsule, Schoeps circuit
Leslie 84 - 3UAudio capsule, Neumann km84 circuit
Oktava Mk-012

Guitar
https://www.youtube.com/watch?v=m-6fQjGiRMo

Mandolin
https://www.youtube.com/watch?v=IcrSdZmqIyg

Nice test.  I like the Leslie84 the best, the Oktava next (I thought the high end was smoother in the 84), then the Scweppes.  I really like the sounds of the 3U capsule on a simple, transformer balanced circuit.

 

[Leslie 123]

As stereo pair L84 and Schweeppes
Bit of plate reverb and compression added
https://www.youtube.com/watch?v=ZDLG5mntANY

 

[Leslie 123]

Nice test.  I like the Leslie84 the best, the Oktava next (I thought the high end was smoother in the 84), then the Scweppes.  I really like the sounds of the 3U capsule on a simple, transformer balanced circuit.

Yes, 84 circuit sounds most true to the instruments, no coloration. Bit more bass Oomph both on Octava and Schoeps circuit, probably L84 transformer is bit shy on bass region but that's nice feature in busy mix. Anyways i winded 3 transformers, 2 mu-metal and one with high nickel content. I'll try to wind one more permalloy but with standard Ei lamination to see what happens. Fun

 

[GraemeWoller]

Wow, winding your own transformers seems like a black art to me! That's super cool!!

 

[RuudNL]

A small sidestep: where do we get 'good' 2N3819 FETs nowadays?
(Not that it really matters, most FETs will work, but the 'phreakz' want the original 2N3819...)

 

[Leslie 123]

A small sidestep: where do we get 'good' 2N3819 FETs nowadays?
(Not that it really matters, most FETs will work, but the 'phreakz' want the original 2N3819...)

FET is acting like a variable resistor changed by audio frequencies. This Fet T1 was changed thru decades in original mic. Funny part, original tuchel version was S2436,  2N3819 came later, probably because of export  and service of mic they found something readily available in US.
Mouser https://hr.mouser.com/Search/Refine?Keyword=2N3819

 

[RuudNL]

Thanks! I will try these.
(Most of the Chinese Ebay/Aliexpress sellers sell 'fake' 2N3819's)
I found that the 2SK30A is a reasonable replacement, but if you repair a microphone, people think you are cheating...

 

[kingkorg]

How do they even manage to kill those fets in the first place?

 

[RuudNL]

I don't know how they do it, but from time to time I get microphones with defective FETs in for repair!
(And people don't trust you when you put something else in than a 2N3819. They say that the microphone will sound different. Well, it doesn't!)

 

[kato]

Leslie, your mandolin playing is fantastic. That's the most important part.

And your mic sounds prettier to me than the Oktava. Congrats!

 

[Matador]

Where are the 3U capsules from? Their web site only shows 47 type LDC's.

 

[fsalter]

Where are the 3U capsules from? Their web site only shows 47 type LDC's.

You have to get in touch with Guosheng directly at 3U
[email protected]