Neumann M49 Clone : Build Thread Puck Style (TLM49 Conversion To M49 b-c)

[Phrazemaster]

I hear you...and actually the 11r is cheaper, at least for me in the states due to Euro conversion.

The sample I heard of Poctop's M49 had a lot of rich full bass, and I believe he just had a T49 in there. So I just decided to go with Max's BV11 and be done with it. I just paid him for it...

Hope your build goes well! Now I'm waiting on riggler's bodies to go into 3rd round of production.

 

[micaddict]

Yes, poctop's M49b with Peluso capsule (later killed in an accident) and AMI T49 tranny, sounded absolutely gorgeous.

 

[poctop]

Yes, poctop's M49b with Peluso capsule (later killed in an accident) and AMI T49 tranny, sounded absolutely gorgeous.

Hey Henk you remember that  ;D ,

Best,
D

 

[micaddict]

You bet.
And I will never forget. 

 

[Phrazemaster]

Hi Dan, I found some nice Shinkoh's but they are .5W, not the 1W you listed in the BOM for the PSU. I don't have a schematic to check to see if I could use a .5W instead - so could I? I don't want to use too low a value...

Also, is this build a "faithful" reproduction of the M49 circuit, or a variation of your own? Not sure if you have already answered this question sorry.

Thx!

Mike

 

[Phrazemaster]

The P.S. BOM shows Rotary Switches SP3T SHRTNG 1.5" ACT
for the pattern select switch only allowing 3 choices.
Can another pot  be used for variable pattern select like the orginal M49? What value?

https://dl.dropbox.com/u/43869772/NUDPW2469P2.pdf

you absolutely can,  if you look at the schematic attached,  all you have to do  is :

use a 100K lin pot ,

and connect the wiper of the pot to the COM pad ,  one side of the pot to OM and the other side of the pot to F8 pad,  this way the pot will act as a voltage divider from 0V omni  to 120V figure 8 ,

I did that this way to avoid having to solder resistor on the 3 pole switch  I used a 3 pol switch cause i am not a very big user of the infinite pattern possiblity
of the mic ,  i am just using fig 8 , omni and cardiod ,  but this will not prevent you of doing this that way , that is why i like DIY , you can make it the way you like , but in this case it is very easy to modify,

Best,
Dan,

Dan what about this pot: http://www.digikey.com/product-detail/en/RV4NAYSD104A/RV4N104C-ND/222811

Is 2W overkill? How low can go? Looks like a nice pot...

And I can still add internal switch S2 across the jumpers even if I use the pot, right? That way can use the pattern on the PSU or the switch on the mic to make it cardioid only?

 

[poctop]

Hi Dan, I found some nice Shinkoh's but they are .5W, not the 1W you listed in the BOM for the PSU. I don't have a schematic to check to see if I could use a .5W instead - so could I? I don't want to use too low a value...

Also, is this build a "faithful" reproduction of the M49 circuit, or a variation of your own? Not sure if you have already answered this question sorry.

Thx!

Mike

you should stick to 1W as this is calculated to make sure the resistor wont heat too much and will stay in the safe zone , I always calculate a little over spec to make sure the psu run as cool as it can,

Yes the Circuit is a faithfull recreaction of the M49b and c version.

Best,
dan,

 

[poctop]

The P.S. BOM shows Rotary Switches SP3T SHRTNG 1.5" ACT
for the pattern select switch only allowing 3 choices.
Can another pot  be used for variable pattern select like the orginal M49? What value?

https://cdn.groupbuilder.com/groupdiy/u/39511/58d0281993f04.pdf

you absolutely can,  if you look at the schematic attached,  all you have to do  is :

use a 100K lin pot ,

and connect the wiper of the pot to the COM pad ,  one side of the pot to OM and the other side of the pot to F8 pad,  this way the pot will act as a voltage divider from 0V omni  to 120V figure 8 ,

I did that this way to avoid having to solder resistor on the 3 pole switch  I used a 3 pol switch cause i am not a very big user of the infinite pattern possiblity
of the mic ,  i am just using fig 8 , omni and cardiod ,  but this will not prevent you of doing this that way , that is why i like DIY , you can make it the way you like , but in this case it is very easy to modify,

Best,
Dan,

Dan what about this pot: http://www.digikey.com/product-detail/en/RV4NAYSD104A/RV4N104C-ND/222811

Is 2W overkill? How low can go? Looks like a nice pot...  not really ,

usually those big pot a 1W or more , there only a tiny current going trough those so 1W will also be fine ,

And I can still add internal switch S2 across the jumpers even if I use the pot, right?
Yes you can

That way can use the pattern on the PSU or the switch on the mic to make it cardioid only?

The Cardiod only switch applies to the same principle as the U47 as it disconnect the rear diaphragme lowering the noise,
this will be an extra switch but does not relate to the pattern switch those are separate things even tough they a related, the cardiod only switch is best to be mounted on the mic as a last resort on the psu,  it could also be activated from a relay from the psu if you wish check the AMI DIY U47 thread they speak about this.

Best,
dan,

 

[Phrazemaster]

Totally awesome Dan! I'll check it out~! Thanks a ton for the great info and support!

 

[Edward]

I found a Mullard 5840 tube, specifications here: http://www.tubecollector.org/cv465.htm

Will it work and is it worth trying in a M49?

 

[Phrazemaster]

Hi Dan, I found some nice Shinkoh's but they are .5W, not the 1W you listed in the BOM for the PSU. I don't have a schematic to check to see if I could use a .5W instead - so could I? I don't want to use too low a value...

Also, is this build a "faithful" reproduction of the M49 circuit, or a variation of your own? Not sure if you have already answered this question sorry.

Thx!

Mike

you should stick to 1W as this is calculated to make sure the resistor wont heat too much and will stay in the safe zone , I always calculate a little over spec to make sure the psu run as cool as it can,

Yes the Circuit is a faithfull recreaction of the M49b and c version.

Best,
dan,

Thank-you Dan, will-do. I had read the schematic for the mic itself which has only .25 and .5w resistors, and got them mixed up...By the way do you have a schemo for the PSU for this build?

Awesome stuff as usual.

I just tried seeing about getting a FleA M49 body, as they have a kit on their website, but Ivan at FleA informed me they are no longer selling the FleA kit. So I'm waiting on riggler...

Mike

 

[poctop]

I found a Mullard 5840 tube, specifications here: http://www.tubecollector.org/cv465.htm

Will it work and is it worth trying in a M49?

if it is a 5840 no problem ,
Best,
Dan,

 

[Phrazemaster]

After a little more research, I decided on getting a honeywell conductive plastic pot for the pattern switch:

http://www.mouser.com/Search/ProductDetail.aspx?R=380C1100Kvirtualkey67810000virtualkey785-380C1100K

Reasoning? Apparently carbon can be noisy, and cermet can wear out...conductive plastic is supposedly the sweet spot with best stability, accuracy, and pot rotation "feel." Oh boy!

Uh...yeah...I really do research each dot and tittle...'till I get another gf that is lol!

 

[Phrazemaster]

I'm working with a cool guy for tubes for this build. Here is some info he shared about the different types of tubes:

The Raytheon grey plate 5840W tubes are going to be nice and warm. The black plate versions will offer greater detail. The GE tubes are a really stout construction and may offer less microphony, however these tubes should not be very microphonic. Sylvania are a nice constuction and are black plate as well.

The RCA tubes are a more sought after tube, but appear to be very similar to the GE version. I also have a high end version of the Air Force 5840A tube from 1957. This is not labelled Jan, but worth mentioning. I only have a few left, they were very popular a few years ago when I had more of them.

He was a super nice guy and cool to deal with; anyone looking for some tubes might hit up http://westubes.com/store2/

 

[Edward]

Funny you should mention the RCA tubes Phrazemaster... I found these tubes yesterday, bought one set of them to try out...

http://www.ebay.com/itm/5x-RCA-CV-3929-EF732-EF-732-Subminiatur-Rohre-NOS-/321105571871?pt=DE_TV_Video_Audio_Elektronenröhren_Valves&hash=item4ac362301f

Black plate version.

 

[Phrazemaster]

Those look good Edward!

I've spent my wad on tubes or I'd maybe snap some of those up too...sigh...DIY is a disease. Glad I got infected.

 

[riggler]

I think it's important to mention here - talking about noise, etc - the importance of cleanliness around the high impedance areas in the circuit. Dirt, solder flux, fingerprints all are bad! Keeping the grid lead routed away from everything else is the most important thing I have read.

I have read that the AC701 tubes were photo-sensitive to camera flashes, so they got painted black. Has anyone read this about other subminis like 5840? I have a bunch of 5840 and 5703 tubes.

I have also seen many pictures of AC701k tubes in mics with all the extra leads not clipped off, coiled up instead. Some have said it was for heat sinking...

Phrazemaster I am pretty sure another run is happening!

And Dany, these PCBs are fabulous!

 

[Phrazemaster]

riggler you just made me very happy! (Especially considering I just popped for a bunch of parts for this thang!). I would "Like" this post twice if I could!

Thanks for your incredible hard work!!

Mike

 

[Phrazemaster]

Question - the Bv11 xformers - will they lack bass extension/low end with a 5840 tube? I'm a little bummed I already ordered a max bv11 but a post said that Oliver has an AMI xformer BV11R that is supposed to be better suited for a 5840 tube...

So I'm wondering if a historic BV11 will be a problem or cause an anemic microphone bass-wise?

Thanks all,

Mike

 

[poctop]

Question - the Bv11 xformers - will they lack bass extension/low end with a 5840 tube? I'm a little bummed I already ordered a max bv11 but a post said that Oliver has an AMI xformer BV11R that is supposed to be better suited for a 5840 tube...

So I'm wondering if a historic BV11 will be a problem or cause an anemic microphone bass-wise?

Thanks all,

Mike

IIRC 0dbfs had a little tweak on one of the cap tie to the kathod on this one , I beleive having a 10 uf instead of a 22uf as the original will thump this one up .
but correct me if i am wrong,  that would be C9 on the C version of the M49.


Best,
DAn,