Neumann M49 Clone : D-M49c and D-M49b Tube Microphone Build Thread. (+Sample)

[poctop]

The Solution For filament Bias Mic PsU version M49b and M269b,  All passive split choke design ,  should be cleanest available option.

To follow up, 
Best,
Dan,

 

[poctop]

Just finished testing the new power supply,  I have built up an M49b this time and tested with this one ,  I am Super happy with the results ,
the 49b filament bias version mic is  Extra quiet and the sound is just awesome ,  I guess this was a very good day , when finishing the power supply i did not even have to touch the POt 8) it was 120V-6V  after warmup.  I installed a 1M ohm pot for the bias and i set it to (4.4V-6 ) = 1.6V bias with 52V plate as results

Now i will have the M269 running soon enough and no worry about the psu beeing noisy , it is just plain whole passive choke filtering full recitfied B+ and heater with a nice array of Big smoother. So Happy now. ;D ;D

I will be replacing the c only version psu with this one and it will also work for the M269b mic coming soon, the M49b version will also be available soon.

 

[poctop]

Here is a simple sample of the D49b,  you can hear very well  that i fall of my chair at the end  ;D

Enjoy :
https://cdn.groupbuilder.com/groupdiy/u/39511/58d0281993aeb.wav

PS: Do Save target as

Best,
Dan,

 

[micaddict]

Sounding good, Dany. 

So, how are you liking the Raytheon 5840?
And have you tried other brands?

Raytheon also has (or had) the 5702 which is very similar but "the only major difference is that that grid 3 (suppressor) comes out on a separate lead this can be tied to the cathode lead on the base". BeesNeez uses that one in some models. Any thoughts about this?



Henk

 

[Tommy Radonicus]

That sounds very impressive Dan. Lots of proximity effect .. By the sound of it you were close to the capsule, but the bottom and top end are both lovely nonetheless. So this is with a 5840 ??

 

[poctop]

That sounds very impressive Dan. Lots of proximity effect .. By the sound of it you were close to the capsule, but the bottom and top end are both lovely nonetheless. So this is with a 5840 ??

thanks I really dig the sound od this mic as well ,  i was close but had a pop filter in the way i know this willl not change that much the proximity much, but this mic has beef to it ,  and yes it is with the Raytheon 5840 tube ,  I was really concerns about the psu for this filament type bias and it sounds quiet big time ,

Best,

 

[micaddict]

Is it the regular or WB version?
(And did you read reply #43? )

it sounds quiet big time

The Brauner Valvet X has a 5840, too.
Noise floor of that mic is below 9 dbA.  8)
Despite "old fashioned" tube and tranny.

 

[Melodeath00]

The mic/clip sounds very good! Lots of proximity, but I dig it.

Are you using an angled headbasket like the 49?

You're planning to do a 269? Will this be very similar to the D67, but use a 5840 instead of EF86?

Thanks

 

[0dbfs]

Dan, This is most exceptional. Looking forward to stuffing some 49b's and c's since the double-choke'd-smoothed-and-stiffened psu will work with either.

Great thing is that you can stuff both a b and c rev fairly economically and use them in the same body/capsule/trafo/psu combo. So stuffing boards with some different tubes (5840/5702) and/or perhaps output caps or whatever allows some adaptability to the record task at hand.

I'm thinking the 269's will be cool too. Especially to open up the options on sourcing tubes.

I haven't looked at the 5702 docs yet but will be checking them out too. I've got about 15x 5840's in stock and the 86 family stuff starts to add up quickly so however you look at it options are always nice

Cheers,
jb

 

[poctop]

Sounding good, Dany. 

So, how are you liking the Raytheon 5840?
And have you tried other brands?

Raytheon also has (or had) the 5702 which is very similar but "the only major difference is that that grid 3 (suppressor) comes out on a separate lead this can be tied to the cathode lead on the base". BeesNeez uses that one in some models. Any thoughts about this?



Henk

Yep That is the standard Raytheon in there i should check out the other model too  the mic will be open to option  ,  i did not have time to try much yet but i am pretty happy with that old plain 5840 from Raytheon nOS for now, have heard of 5748WB or somthing similar as well,
this will be fun experiment with those minis 

 

[poctop]

You're planning to do a 269? Will this be very similar to the D67, but use a 5840 instead of EF86?

Thanks

Yes it is in process already see the other thread .
Best,
dan,

 

[micaddict]

have heard of 5748WB or somthing similar as well,

Yes, there are several, like the 5702, CV4501 and CV4502, that are very similar though not the same.

BTW the military grade (JAN, WA, WB and such) is an interesting matter. Some say these are the same as the standard versions, only more rugged. Others don't agree.
Here's what Oliver Archut wrote about it in 2002 on the Neumann forum:

JAN tubes, Join Army Navy tube key, specialty tubes made for military use. Most of them were upgraded industrial tubes, with the one purpose to insure function under very heavy-duty circumstances. Their construction was designed to insure the minimal function over a long period of time. To put it into better terms, there were pre tested on the edge of their rating to sort out early failing ones. It doesn't mean that they were tested for audio, and most of those tubes are very noisy, not microphonic but a lot of random and white noise. In circuits like the U67 most of it is suppressed because of the HF cut off feedback as you pointed out. The higher noise relates to the cathode construction, some of them used sintered ones others a double layer coating design, the first layer is fast activated at the factory, the second one starts activating over a long period of time. *This process was patented by Sylvania and use for most JAN tubes after 1963* That is what generates the higher noise floor if used for audio. Sure they nearly live forever with hardly no microphonics, but gain structure is quite different, most of them sound quite harsh. In the last few years so many JAN tubes were decommissioned and entered the audio market, but for my personal taste a standard RADIO GRADE or some industrial tubes are more desirable. Of course there are some exception, like the JAN tubes than were special made for audio use.

For those who don't know, Oliver Archut is the same guy who makes the T49 tranny as used for this here M49 project. And yes, he does know a thing or two about tubes, too.

Of course, highly regarded mic builders like Dirk Brauner, the earlier mentioned Ben Sneesby and others do use military grade tubes with great success. Perhaps these tubes are the exception Oliver talks about in the last sentence of the quote. (?)

Here's a discussion that took place on another forum in 2005:
http://www.diyaudio.com/forums/tubes-valves/53836-difference-between-5687-5687wa-5687wb-tubes.html
It's just one discussion and simply the first that popped up.
For more in depth discussions about this (like Oliver Archut's story), one's best bet IMO would be to search in the archives of Klaus Heyne's excellent REP forum.
Come to think of it, our own forum may hold some useful ones, too.

Oh and as a rule the standard version tubes are cheaper.

 

[poctop]

Is it the regular or WB version?
(And did you read reply #43? )

it sounds quiet big time

The Brauner Valvet X has a 5840, too.
Noise floor of that mic is below 9 dbA.  8)
Despite "old fashioned" tube and tranny.

I double checked and it seems i have the Raytheon 5840W series, i will use the same one for now in the M269 Build 

Best,

 

[micaddict]

Thanks, Dany.
The 5840 in the Brauner is a Philips JAN, BTW. The tranny a custom Lundahl.

 

[poctop]

Thanks, Dany.
The 5840 in the Brauner is a Philips JAN, BTW.

thanks,  good to know, once this is all working and tested i will have some fun with other tubes and i will keep that one in mind , I will be orering different flavor and bias those and see 

Best,
Dan,

 

[gary o]

http://proel.com/category/products/ldf410

Any use

 

[0dbfs]

Thanks, Dany.
The 5840 in the Brauner is a Philips JAN, BTW.

thanks,  good to know, once this is all working and tested i will have some fun with other tubes and i will keep that one in mind , I will be orering different flavor and bias those and see 

Best,
Dan,

I'll try out some other tube options too.

Cheers,
jb

 

[gary o]

http://www.thomann.de/gb/media_bdbviewer_AR_165293.html?image=4

very cheap maybr good for a body

 

[poctop]

http://www.thomann.de/gb/media_bdbviewer_AR_165293.html?image=4

very cheap maybr good for a body

not sure this one will fit the aMI T49 is one piece of iron to fit in amic body for sure,
Dan,

 

[poctop]

Here the first Sample ,  it looks sweet just looking at the wav form in the DAW 

AMI T49-ChuckD M7

let me know what you think,

Best,
https://cdn.groupbuilder.com/groupdiy/u/39511/58d0281993c83.wav